Title: Phys 3120 / Final
Tags: GastrointestinalSystem EndocrineSystem RespiratorySystem ReproductiveSystem Females

Q: Gas exchange happens both in the [...] system and the [...] system
A: respiratory; systemic

Q: The [...] is both a structure of the lung and also a function.
A: blood gas barrier

Q: In the lungs, O2 goes [...] and CO2 [...], but it is not 1:1.
A: in; out

Q: In the systemic tissue, O2 goes [...] of blood and CO2 [...], but it is not 1:1.
A: out; in

Q: Typically, blood gas values are taken from the [...]
A: systemic arteries

Q: Fick's Law of Diffusion
Vgas = [...]
A: constant*(P1-P2)*A/Thickness

Q: Fick's Law of Diffusion
Diffusion constant is proportional to [...] and inversely proportional to [...]
- Ie, larger molecules make a [...] constant
A: gas solubility; sq root of mass; smaller

Q: Partial Pressure is the pressure of [...]
A: each gas

Q: O2 concentration in the air is [...]
A: 21%

Q: In the lung, there is 47 mmHg of [...] pressure, so the pressure of [...] is 713 mmhg (smaller than atmospheric 760) and thus the PO2 in the lung is also [...] than atmospheric
A: water vapour; air; lower

Q: Partial pressure does not depend on the [...] of a gas in solution, because it is equal to the pressure of gas in [...] with the solution, not dissolved in it.
A: solubility; equilibrium

Q: [...] is the partial pressure of [...]
A: PaO2; O2 in arterial blood

Q: The blood gas barrier controls both the [...] and the [...] in Fick's Law.
A: A; T

Q: Blood Gas Barrier
Type [...] Cell
- [...]
A: 1; Thin flat cells which line the alveoli

Q: Blood Gas Barrier
[...]
- [...]
A: Interstitium; Structural component

Q: Blood Gas Barrier
[...] cell
- [...]
A: Endothelial; Lines the capillary side

Q: Blood Gas Barrier
[...] layer
A: Surfactant

Q: There is significant [...] in the lungs to result in the large SA we see.
A: branching

Q: Airways: [...]
A: Structural units which branch

Q: Alveoli: [...]
A: Blood gas barrier

After the trachea, it branches off into 2 bronchi, then bronchioles, all the way down to terminal bronchioles, which are the final component of the conducting zone.

After the terminal bronchioles, it branches off into respiratory bronchioles, then alveolar ducts, all the way down to alveolar sacs, which are the final component of the respiratory zone.

Q: There is no gas exchange in the [...] zone of the lungs
A: conducting

The intrapleural space has a pressure of -5 mmHg
- This is due to the elastic/inwards properties of the lung and the chest wall wanting to move outwards

If a pneumothorax (hole in the diaphragm) is made, intrapleural pressure becomes atmospheric and the lungs collapse and the chest expands

Q: In the pulmonary system, extensive [...] of capillaries also occurs.
A: branching

Q: Ventilation: Process by which [...]
- If intrapleural pressure is more [...], air flows [...] the lungs.
A: air moves into and out of the lungs; negative; into

Inhalation
Active process: Contraction of inspiratory muscles such as the diaphragm and external intercoastals.
- Makes interpleural pressure more negative

Q: Exhalation
[...] process: Relaxation of [...] muscles
A: Passive; inspiratory

Exhalation
Active process: Occurs during exercise or hyperventilation and involves contraction of muscles in abdominal wall and the internal intercostals

Q: Relatively [...] changes in the pressure of the lung can result in sufficient inflation.
A: small

Q: Lung Compliance = [...]
A: deltaV/deltaP

Q: Lung Compliance is defined as the [...] per change in [...]
A: volume change; pressure

Q: If the diaphragm has a hole, [...]
A: lungs collapse and chest expands

Q: If internal intercostals are cut, can't [...]
A: exhale forcefully

Q: During inflation, after a certain pressure, the lung becomes way more [...], up to a [...] point.
A: compliant; plateau

Q: During deflation, the lung [is/isnot] initially compliant, but then becomes so.
A: is not

PV Curve of Isolated Lung
3 Important Features
1) Non linear curve.
2) At high/low volumes, the lung is less compliant
3) At same pressure, the lung has more volume during deflation compared to inflation, this is called hysteresis

Q: Lung [...] and [...] are responsible for compliance.
A: elasticity; surface tension

PV Curve with Saline
If the lungs are filled with saline, surface tension goes to 0.
Compliance goes up, and only 1/3 the normal pressure is required to overcome the elastic properties of the lung.
- Also no histuresis

Lung Elasticity
- Fibers of elastin and collagen are present throughout the lungs.
- Elastin can stretch and collagen cannot stretch

Q: Surface Tension
- Bubbles form because spheres have the [...] SA out of any shape for a set volume.
A: smallest

Q: [...] pressure is required to overcome the [...] properties of the lung.
A: 2/3; surface tension

Q: Surface tension makes it [...] to expand the bubbles, because with higher volumes, comes [...] water molecules at the surface.
A: difficult; more

Surface tension also makes air flow from smaller bubbles to the larger ones, because more air can fit, without significantly increasing water molecules at the surface.
- Hence, small bubbles collapse

Q: Surfactant helps prevent [...] surface tension, avoiding [...] pressure being required to inflate the lungs and [...] of small alveoli
A: high; high; collapse

Q: At small volumes, the force of [...] is high! (think of the elephant exploding)
A: suface tension

Q: Surfactant decreases surface tension the most during [...], since the surfactant is compressed.
A: exhalation

Q: Laplace's Law
[...] = [...]
- Ie. Lower surface tension = lower [...] requirement
A: deltaP; 2*surfacetension/r; pressure

Q: Due to surfactant, surface tension at low lung volumes is [...] and high lung volumes is [...], this means a [...] pressure difference needs to be made at high lung volumes.
A: low; high; greater

Q: Pulmonary surfactant consists of [...] and [...] (which generate the surface film).
A: lipids; proteins

Q: Surfactant is secreted by [...] cells
A: alveolar type II

Q: [...]: [...]
A: Minute Volume; Volume of air inhaled per minute

Q: Minute Volume = [equation]
A: Respiratory Rate*Tidal Volume

Q: [...]: [...].
A: Vital Capacity; Volume of air which can be forcibly exhaled after a maximal inspiration

Q: [...]: [...]
A: Inspiratory Reserve Volume; Volume of air which can be forcibly inhaled following a normal inspiration

Q: [...]: [...]
A: Expiratory Reserve Volume; Volume of air which can be forcibly exhaled following a normal expiration

Q: [...]: [...]
A: Maximal Voluntary Ventilation (Breathing Capacity); Volume of air moved into and out of the lungs in one min by voluntary effort

Q: [...]: [...]
A: Residual Volume; Volume of air remaining in the lungs after maximal expiration

Q: [...]: [...]
A: Functional residual capacity; Volume of air remaining in the lungs after normal expiration

Q: Total Lung Capacity = [...] + [...]
A: residual volume; vital capacity

Q: FEV1 is the [...] expired in one second
A: fraction of VC

Q: FEV1 is [...] in asthmatics
A: decreased

Q: [...] and anything which depends on it, cannot be measured using [...]
A: Residual Volume; spirometry

Q: Helium Dilution Method
- Works because [...]
A: helium doesn't pass through blood gas barrier

Q: Helium Dilution Method
- Equation of relevance is [...]
A: CV_T = C(V_T+VFRC

Q: [...] is the same thing as [...]
A: Pulmonary Ventilation; minute volume

Q: Alveolar Ventilation = [...]
A: Pulmonary ventilation - Dead space ventilation

Q: If tidal volume is low, almost all of the air will be in the [...], so alveolar ventilation is low.
A: anatomic dead space

Q: [...] dead space is a consequence of [...].
A: Anatomic; the structure of the lung, conducting zone doesn't do gas exchange

Q: [...] dead space is the [...].
- Consequence of lack of [...] in certain areas.
A: Physiological(total); total air which doesnt participate in gas exchange; bloodflow

Q: Gas exchange of [...] is very efficient, so alveolar PCO2 basically is the same as [...] PCO2
A: CO2; arterial

Q: We can control respiration voluntarily through the [...] tract, but eventually the [...] takes over again.
A: corticospinal; ANS

Q: The [...] receives information from [...] and sends information to the respiratory muscles.
A: central controller; receptors

Q: The [...] collect information about blood gases and other factors.
A: receptors

Central Controller
1) Inspiratory area
Location: Dorsal neurons in the medulla
- Responsible for inspiratory drive and have inherent rhymic excitability.

Central Controller
1) Pneumotaxic area
Location: Neurons in the pons
- Responsible for fine-tuning respiration, and control of inspiratory volume and rate
- Also inhibits prolonged inspiration

Central Controller
1) Apneustic center
Location: Neurons in the lower pons
- Responsible for prolonging inspiration, and is overridden by the pneumotaxic center.

Central Controller
4) Expiratory area
Location: Ventral neurons in the medulla
- When needed, these neurons send signals to expiratory muscles for active expiration.

Q: You can get the benefits of [...] altitude training at low altitude if you sleep in a [...] with low O2.
A: high; tent

Receptors
Central Chemoreceptors
- Location: Located in the medulla where they are surrounded by brain fluid.
- Responds to blood PCO2 indirectly, since it actually measures H+

Receptors
Peripheral Chemoreceptors
- Location: Located in the aortic arch as well as located in the carotid bodies in the carotid arteries.
- In humans, the receptors in the carotid bodies are more responsive.
- Responds to changes in O2, increasing ventilation if it drops below 60 mmHg.
- Also minor responses to PCO2 and pH

Receptors
Lung Receptors
- Location: Lung.
- Detect stretch/overdistention to slow respiration.
- Also respond to irritants

Q: Receptors
- Other receptors such as those in the [...] can respond to [...].
- [...] receptors during exercise.
- Pain and termperature receptors.
A: nose; mechanical strains; Muscle

Q: If there is obstruction in the lungs, [...] levels [...], thus capillaries may [...] to divert blood away
A: CO2; increase; constrict

Q: If there is obstruction in the lungs, CO2 levels may not increase, but rather not [...], thus capillaries may [...] to divert blood away
A: change; constrict

Q: Pneumothorax
- Air in the [...].
- Spontaneous or through injury.
- Treatment may include [...].
A: intrapleural space; insertion of a tube to suck out the air

Inhaled Particles
Clearance
1) Mucus (in larger airways, traps big stuff).
2) Aleveolar Macrophages

Q: Inhaled Particles
- The biggest pollutants people experience now are [...], vaping, cigarette smoke and [...] (yellow smog).
A: carbon monoxide; nitrogen oxide

Q: Carbon monoxide kills people because it has a [...] compared to O2.
- Treatment involves [...] administration.
A: higher affinity for Hb; oxygen

Q: CO is a colourless/[...]less gas created by [...] combustion.
- Symptoms include [...] and a headache.
A: odour; incomplete; fatigue

Q: Cigarretes cause [...], which is the destruction of alveoli which leads to COPD.
A: emphysema

People with emphysema experience CO2 retention.
- Abormal results in a pulmonary function test
- Treated with oxygen and avoiding pollutants

Neonatal Respiratory Distress Syndrome
- The lung is the last major organ to develop.
- A consequence of this is that premature babies have very poor lung function, specifically due to decreased lung compliance caused by a deficiency in surfactant

Q: Neonatal Respiratory Distress Syndrome
- Surfactant is NOT just composed of [...], certain [...] are also very necessary!
A: phospholipids; proteins

Q: Neonatal Respiratory Distress Syndrome
- Surfactant is used to treat babies with this disease, and to do so, it must first be isolated from [...]!
A: cows

Acute Respiratory Distress Syndrome
- Defined by low PaO2.
- Can be caused by near drowning, infections.
- High mortality rate.
- Change in lung physiology involves decreased lung compliance

Q: Acute Respiratory Distress Syndrome
- Surfactant is present, but [...].
- Hard to treat because [...] can't really clear out liquid from their lungs (if you add surfactant).
A: dysfunctional; adults

Acute Respiratory Distress Syndrome
- Another crazy treatment method is through liquid ventilation.
- Uses perfluorocarbon, which has high O2 solubility.
- Our body kind of rejects this treatment method

Q: Acute Respiratory Distress Syndrome
[...] ventilation can also be used, but might overly stretch/damage the lungs.
A: Mechanical

Q: [...] lung diseases involve [...].
- Examples include [...] and obesity.
A: Restrictive; difficulty expanding the lung; fibrosis

Q: [...] lung diseases involve difficulty [...].
- Examples include [...] and asthma.
A: Obstructive; exhaling; COPD

Q: Asthma
- [...] of the airways causes constriction.
A: Inflammation

Q: Asthma
- Diagnosed either using [...] or a chest [...]
- Alternatively through measuring [...]
A: medical history; X-ray; FEV1

Q: Asthma
- The FEV/FVC ratio in asmatics should be less than [...]
A: 60%

Q: Asthma
- The FEV in asthmatics is greatly [...]
A: reduced

Q: Asthma
- Treatments involve broncho[...] or anti[...]
A: dilators; inflammatories

Q: The endocrine system releases [...] into the [...] to communicate with other tissues.
A: hormones; blood

Q: [...] can affect just [...] organ or [...].
A: Hormones; one; many

Q: Hormones can function at very [...] concentrations, and often regulate their own synthesis through [...] feedback.
A: small; negative

Q: [...]: [...].
A: Endocrine; Hormones are made in one part of body and act on a distant part

Q: [...]: [...].
A: Paracrine; Hormones act on neighbouring cells

Q: [...]: [...].
A: Autocrine; Hormones act on same cell

Steroid Inactivation (Liver)
- Steroids are inactivated by the liver, either by changes to the ring structure or conjugation to acids, allowing for excretion in urine.

Q: The main mechanism of gradation in the endocrine system is [...] modulation, not changes in [...] of release.
A: amplitude; frequency

The three main classes of hormones are:
1) Peptides, which are watersoluble and can be monomers or multimers.
2) Steroids, which are derived from cholesterol metabolism and compose of 4 rings.
- These are lipid soluble, so they need protein carriers
3) Amino acid derivatives.

Q: Regulation of Endocrine Secretion
1) Between [...]
- Eg. T3 decreases release of TSH.
A: 2 hormones

Q: Regulation of Endocrine Secretion
1) Between [...]
- Eg. PTH increases Ca and Ca decreases PTH.
A: a hormone and a metabolite

Q: Regulation of Endocrine Secretion
1) Between [...] hormones
- Eg. Glucagon and Insulin
A: antagonistic

Human Endocrine System
- The gut releases hormones which regulate digestion/food absorption.
- The heart secretes ANP.
- The kidney secretes EPO (erythrocyte maker).
- The liver secretes angiotensinogen and thrombopoetin.
- The adipose tissue secretes adipokines.
- Most cells produce local factors.

Steroid hormones travel into cells down their concentration gradient and bind to transcription factors/hormone receptors.
- The receptors then travel into the nucleus and amplify hormone action by producing multiple copies of mRNA from one molecule of steroid.

Q: In the testes, [...] increases [...] release, which can be made into [...] which is even more potent!
A: LH; testosterone; DHT

Q: Factors Affecting Hormone Action
1. Hormone [...]
- Regulation of [...] expression.
- Availability of necessary [...]
A: production/release; gene; substrates

Q: Constant exposure to high levels of hormone may eventually lead to [...] of the receptors.
A: downregulation

Q: Variable release of hormones into the blood helps prevent [...] of receptors!
- Also helps promote [...]
A: downregulation; negative feedback

Q: Factors Affecting Hormone Action
2. Serum [...]
- Help alter [...], clearance, [...] etc.
A: Proteins; bioavailability; solubility

Q: Factors Affecting Hormone Action
3. [...] enzymes.
A: Converting/deactivating

Q: Factors Affecting Hormone Action
4. [...] by the kidney/liver.
A: Clearance

Q: Factors Affecting Hormone Action
4. [...] and signal transduction
A: Receptors

Q: Signal Amplification
- Each hormone produces multiple [...], which all activate different cascades.
- End generation of multiple copies of product.
A: secondary messengers

Q: Hormone Receptors
- Lipid-soluble ligands are [...], vitamin [...], [...] acid.
A: steroids; D; retinoic

Q: [...] are the receptors for LH, GnRH, angiotensin
A: GPCRs

Q: [...] are the receptors for insulin, NGF
A: RTK

Q: [...]: [...].
A: Circadian; Roughly 24 hour cycle

Q: [...]: [...].
A: Diurnal; Exactly 24 hour cycle, eg. cortisol

Q: [...]: [...].
A: Ultradian; Minutes or hours

Q: Cortisol levels peak before [...]
A: waking

Q: Hypothalamus
- Short [...] neurons secrete releasing hormones into the [...] pituitary through the hypophyseal portal system.
A: parvicellular; anterior

Q: Hypothalamus
- Long [...] neurons secrete releasing hormones into the [...] pituitary directly.
A: magnocellular; posterior

Q: Hypothalamus
- The primary hormones released by the [...] pituitary are [...] and [...]
A: post.; vasopressin; oxytocin

Hypothalamus
- The primary hormones released by the ant. pituitary are ACTH, TSH, LSH, FSH, prolactin and GH

Q: You have to take recordings at [...] time everyday to get a good idea of hormone levels, because they change so much!
A: same

Major Hypothalamic Factors
- Vasopressin, aka ADH and AVP is released to inc. plasma volume and pressure

Major Hypothalamic Factors
- Oxytocin is released due to vaginal stimulation and/or suckling and it functions to increase vaginal contractions and milk production.

Q: Major Hypothalamic Factors
- Oxytocin has secondary affects such as alterations to [...] response, BP/HR, [...] behaviour, as well as tubule contraction in [...]
A: stress; feeding; testes

Major Hypothalamic Factors
- Oxytocin has secondary affects such as alterations to stress response, BP/HR, feeding behaviour, as well as tubule contraction in testes

Q: Major Hypothalamic Factors
- [...] functions to [...] release of [...]
A: Somatostatin(SST); inhibit; GH

Q: Major Hypothalamic Factors
- [...] functions to [...] release of [...]
A: Dopamine; inhibit; prolactin

Q: Major Hypothalamic Factors
- All hypothalamic hormones bind to [...] receptors.
A: GPCR

The superchiasmatic nucleus receives input from the retinas and resets gene pattern to correspond to the day/night cycle.
- Resets activity of clock genes (Per and Cry)

The pineal gland receives information from the SCN through the spinal cord.
- Produces melatonin during dark periods.
-- This hormone functions to dec. body temp, promote drowsiness and reset clock genes

Hypothalamic-Adrenal Axis
- Parvicellular cells secrete CRH (peptide)
- CRH acts on ant. pituitary to release ACTH.
- ACTH acts on Adrenal gland to produce Cortisol.

Hypothalamic-Adrenal Axis
- Cortisol functions to increase blood glucose, through an increase in gluconeogenesis and muscle catabolism but an inhibition of GLUT4
- Negative feedback inhibits CRH and ACTH production

POMC is a precursor to many hormones including ACTH and endorphins.
- Turned into different hormones through post-translational processing

Hypothalamic-Pituitary-Adrenal Axis
- CRH release is increased due to immune stress and physiological stress, but neural stress will dec. CRH release if the frontal cortex is stimulated, and inc. if the amygdala is stimulated.

Hypothalamic-Pituitary-Adrenal Axis
Addison's disease
- Form of hypocortisolism due to adrenal degradation.
- Leads to high levels of ACTH.
- Caused by autoimmune disorders.
- Symptoms include fatigue, low bp.

HP-Thyroid Axis
- Parvicellular cells secrete TRH (peptide)
- TRH acts on ant. pituitary to release TSH.
- TSH acts on thyroid gland to produce T3/T4.
- Negative feedback from T3/T4 and also SRIF onto TSH.

HP-Growth Axis
- GH acts on liver to produce IGF1 for growth.
- Acts on bone to promote repair
- Helps produce leptin, which increases GH release,decreases bone formation, and also dec. appetite.

Q: HP-Growth Axis (Growth Hormone)
- IGF1 engages in [...] feedback
- SRIF engages in [...] feedback
- Leptin engages in [...] feedback
A: negative; negative; positive

Q: During development, the hormonal axis develop [...], based on the available [...] factors.
A: one at a time; transcription

HP-Gonadal Axis
- Parvicellular cells secrete GnRH (peptide)
- GnRH acts on ant. pituitary to release LH and FSH.
- LH/FSH act on gonads to produce steroid hormones.
- Important axis for gametogenesis.
- Negative feedback from steroid hormones.

HP-Prolactin Axis
- Parvicellular cells secrete TRH/PRF (peptide)
- TRH/PRF acts on ant. pituitary to release prolactin.
- Prolactin acts on breasts to promote milk production.
- No negative feedback! Only dopamine has an inhibitory effect.

Q: Thyroid Gland
- Produces T3, T4 and [...]
A: calcitonin

Q: Thyroid Gland
- Thyroglobulin contains [...] residues and is the substrate used to form T3/T4.
A: tyrosine

Q: Thyroid Gland
- Iodine is very important for making [...] and it is attained through our [...], specifically through [...].
A: T3/T4; diet; dark greens

Thyroid Gland
Role of Thyroid Hormones
A) Growth and development
- Required for GH secretion and action.
- Necessary for neural development through NGF
- Maternal lack of T3/T4 leads to growth retardation and cretinism.

Q: Thyroid Gland
Role of Thyroid Hormones
B) Stimulate [...]
- Increases [...]
A: mitochondria; basal metabolic rate

Q: Thyroid Gland
Role of Thyroid Hormones
C) [...] other hormones.
A: Upregulates

Q: Thyroid Gland
Role of Thyroid Hormones
D) Increase [...] enzymes.
- Causes an increase in [...] and glycogenolysis.
A: energy metabolism; gluconeogenesis

Thyroid Gland
Thyroid Peroxidase is the enzyme which actually produces T3/T4.
- Iodinates the tyrosine residues then couples two of them together.
- Functions at the apical membrane.

Thyroid Gland
Synthesis
- TSH binding creates cAMP which goes onwards.
- Na^+/I^- Symporter (NIS) transports iodide from the bloodstream across the basolateral membrane into follicular cells
- Pendrin transports iodide from the follicular cell lumen across the apical membrane and into the colloid.

Thyroid Gland
Synthesis
- TPO first iodinates thyroglobulin either one time or twice
- Then, TPO couples either a monoiodotyrosine with a diodotyrosine to make T3 or two diiodotyrosines to make T4.
- Hormones are pinocytosed into follicular cells
- Proteolysis of Tg-T3/T4 to release thyroid hormones from Tg

Q: Thyroid Gland
TSH ACTION
- Increases activity of [...].
- Increases production of [...]
- Increased activity of [...]
A: NIS; Tg; TPO

Q: Thyroid Hormone Transport
- [...] carries most of T3/T4 in the blood, but [...] and [...] also help improve the bioavailability of T3/T4.
A: TBG; TTR; albumin

T4->T3
- T3 is the active form of the hormone and binds TH receptors inside the nucleus.
- If T4 enters the cell, it can be converted to T3 by D2 (deiodinase) enzyme.
- D3 enzyme inactivates T3 by making it into rT3

Q: T4 binds [...] strongly to plasma proteins than T3.
A: more

Q: Goiter is caused by excessive [...], which leads to hyper[...] of the thyroid.
A: TSH; trophy

Q: Hashimoto's Disease
- Causes [...]thyroidism.
Mechanism: [...].
- Leads to an [...] body phenotype.
A: hypo; Antibodies against TPO block iodination of thryoglobulin; immature

Q: The most important symptom of hypothyroidism is a lack of [...]
A: energy

Q: The most important symptom of hyperthyroidism is too [...] energy.
A: much

Graves' Disease
- Causes hyperthyroidism.
MECHANISM: TSH antibodies activate receptor and produce T3/T4.
- Eye protrusion and goiter are two symptoms which are important and both occur in the head region.

Q: Importance of Ca2+
- Calcium is an important [...] for enzymes, useful in muscle contraction and signal transduction.
A: cofactor

Q: Importance of Skeleton
- Primary method of [...] calcium.
A: storing

Q: The net change in Ca2+ in our body is [...]
A: 0mg

Q: Some calcium in the blood is [...] and some is [...]
A: free; bound

Q: 99% of all calcium is stored as [...] in the bones.
A: hydroxyapatite

Q: The [...], [...] and [...] play important roles in calcium balance.
A: intestines; kidneys; bone

Q: Intestinal Absorption of Calcium
- Calcium transport works using the same transporters as in the [...]
- Excess Ca is excreted in [...].
A: kidney; feces

Q: Calcium Absorption in Kidney
- Can be absorbed at the bottom of the [...]
- Can be absorbed in the [...] through active transport.
- Upregulated by [...]
A: descending loop of henle; DCT; PTH

Q: [...] bone is metabolically active
- Constantly being [...] and [...], releasing Ca.
A: Trabecular; degraded; repaired

Q: [...] form bone.
A: Osteoblasts

Q: [...] degrade bone
A: Osteoclasts

Q: [...] coordinate remodelling
A: Osteocytes

Remodelling cycle
- Osteoclasts degrade bone to form a resorption pit.
- Osteoblasts are recruited and fill pit with osteoid
- Mineralization finally occurs, and Ca is stored.

Q: Remodelling cycle
- With aging comes an [...] of formation/reabsorption and [...] can occur.
A: imbalance; osteoporosis

Q: Parathyroid
- [...] cells have 2 main functions:
1) [...].
2) [...]
A: Chief; Create parathyroid hormone; Sense Calcium

Parathyroid
- PTH is a peptide hormone and has full biological activity if it only has the 1-34 fragment.
- Binds to PTH Receptor, which functions to increase calcium levels in the body.
This receptor also binds to PTHrP, which is a growth factor in function.

Q: Parathyroid
- If Ca levels are low, there is [...] PTH secretion.
A: more

Q: Parathyroid
- If Ca levels are high, there is [...] PTH secretion.
A: less

PTH Effects
- Causes an increase in bone resorption and decrease in bone formation.
- Increase in reabsorption of Ca in the DCT.
- Increase in activity of a-hydroxylase, which helps make vitamin D3.
This hormone functions to inc. reabsorption of Ca in the intestines

Vitamin D Metabolism
- Sunlight converts precursors in the skin into cholecalciferol, which can also come from the diet.
- The liver converts it then to 25-hydroxylase, which is the circulating form.
- The kidneys finally create active D3

Vitamin D Metabolism
- Vitamin D3 functions in the gut to increase calcium reabsorption.
- Increases bone reabsorption, when calcium levels are low.
- Increases bone mineralization when calcium levels are high.

Q: A deficiency in vitamin D causes [...].
- Can be common in places with a lot of [...].
A: rickets; pollution

Q: Insulin release after consumption of food has [...] peaks (biphasic).
- This causes a [...] in blood glucose.
- Also experience a [...] in glucagon levels.
A: 2; decrease; drop

Cellular Respiration
1) Glycolysis: Conversion of glucose to pyruvate, also producing 2 ATP.
2) Pyruvate dehydrogenase: Converts pyruvate to acetyl-coA.
3) Citric acid cycle: Converts acetyl-coA into oxaloacetate.
4) Electron transport chain: Produces the majority of the ATP, to bring the total up to 38

Glucagon, GH, cortisol and epinephrine all increase blood glucose.

Q: There are [...] different glucose transporters, each with different [...] and locations.
A: 5; properties

Q: Pancreas
- [...]-cells are found in the [...] of each islet.
A: a; periphery

Q: Pancreas
- [...]-cells are found in the [...] of each islet.
A: b; core

Q: Pancreas
- d-cells produce [...]
A: somatostatin

Q: Pancreas
- D1-cells produce [...], which is involved in [...] balance.
A: VIP; electrolyte

Q: Pancreas
- PP-cells produce [...], which is involved in [...].
A: PP; proteolysis

Insulin Biosynthesis
- In the Nucleus, pre-proinsulin is made.
- It moves to the ER, where the N-terminal is removed to produce proinsulin.
- In the golgi, endopeptidases (PC1/2/3) cleave the C-chain
- Also in the golgi, exopeptidases clean up the C-terminus to make the final active molecule.
- Insulin is then stored in vesicles

Q: Biphasic release of insulin occurs because the [...] of secretory vesicles have to be re[...].
A: stockpile; produced

Insulin Release

Phase II of Insulin Release
- Influx of calcium activates CAM-kinase which increases transcription of the relevant gene.
- Insulin binding to the receptor can also cause phosphorylation of IRS1, which also increases transcription.

Q: The insulin receptor is an [...], which means it must [...] before it can bind substrate.
A: RTK; dimerize

Q: In metabolic organs, insulin receptor activation causes an increase in glucose [...], through the [...] of GLUT4 channels.
A: reuptake; translocation

Signal Termination
- Insulin effects are terminated by:
1) Phosphatases inactivating receptors
2) Ca2+ being pumped out of cells
3) Phosphodiesterase inactivating GTP
4) Transcription factors being dephosphorylated

Q: Other Functions of the Insulin Receptor
- Decreases [...] of b-cells
A: apoptosis

Neural Control of Glucagon
- CNS/SNS are stimulated in response to low glucose.
- Norepinephrine is released onto a cells to create glucagon.
- Epinephrine from the adrenal medulla also promotes glucagon production, as well as glycogenolysis

Q: Major Roles of Insulin
- In the muscle
1) Inc [...]
2) Inc [...]
3) Inc [...]
A: glycogenesis; glucose uptake; protein synthesis

Q: Major Roles of Insulin
- In the adipose tissue
1) Inc [...]
2) Inc [...]
3) Inc [...]
A: fatty acid and glucose uptake; lipogenesis; leptin secretion

Q: Major Roles of Insulin
- In the brain
1) Dec [...]
A: hunger

Glucagon
- Promotes glycogenolysis and gluconeogenesis.
- Inc. lipolysis, Inc. muscle breakdown etc.
- Stimulated by fall in blood glucose, or an increase in blood AA or CCK.
- Does not affect leptin function.

Adipo-Insular Axis
- Insulin promotes leptin production in the adipose tissue.
- Leptin functions to decrease insulin, dec. hunger, and inc. energy use.

Q: Adipo-Insular Axis
- Stress activates the SNS, which [...] insulin release.
A: inhibits

Incretins
- Released in response to oral glucose.
- Augment insulin response, by increasing intracellular Ca
- Inactivated by DPP

Q: Diabetes is characterized by [...]glycemia and [...] urine volume.
- In severe cases, [...], retinopathy and angiopathy are noted.
A: hyper; high; ketoacidosis

Q: Type I diabetes is [...] onset
A: early

Q: Type II diabetes is [...] onset
A: late

Q: Type I Diabetes
- A failure to [...] enough insulin, as a result of [...] destruction of b cells.
- A [...] of energy is a common symptom.
A: secrete; autoimmune; lack

Type I Diabetes
- Without insulin, gluconeogenesis increases, involving a breakdown of muscle tissue to supply amino acids and breakdown of fat (lipolysis) to supply fatty acids and ketones

Q: Type I Diabetes
Effects of High Glucose
- Conversion of glucose to [...] is very damaging to [...] and the lens.
A: sorbitol; nerves

Q: Type I Diabetes
Effects of High Glucose
- Synthesis of [...] causes nephropathy.
A: DAG

Q: Type II Diabetes
- Insulin resistance can cause [...] or [...]
A: type II diabetes; Ovarian Cysts (PCOS)

Type II Diabetes
Insulin Resistance
- One mechanism is improper phosphorylation of the insulin receptor, which leads to lower activity in the pathway.
- Recall, the insulin receptor is involved in increasing insulin  transcription in addition to translocation of GLUT4.

Insulin Resistance
- Another mechanism is that adipocytes in obese patients have fewer insulin receptors.
- In addition, typically have serine phosphorylation (inactivating), instead of tyrosine phosphorylation (activating).

Insulin Resistance
Obesity
- Adipose tissue becomes stressed/overloaded, inducing the activation of IRE-1, which causes a dec. in insulin receptor signalling.
- In addition, XBP is formed, which functions to dec insulin receptor transcription.
- Essentially, the tissue is shutting down its metabolism.

Obesity and Insulin Resistance
1) Increased secretion of cytokines, which causes phosphorylation of serine, an inactivating phosphorylation.
2) Decreased secretion of adiponectin, which causes an increase in gluconeogenesis and decreased glucose uptake.
- Overall, causes increased fatty acid levels.

Q: Insulin Resistance
- PPAR gamma levels are [...] in diabetes.
- In diabetes, this means that there is [...] glucose storage/metabolism.
A: decreased; less
Extra: PPAR GAMMA DECREASES BLOOD GLUCOSE

Q: Insulin Resistance
- Mutations in the [...] gene are usually lethal.
A: InsR

Q: Insulin Resistance
- Low in utero weight is correlated to inc. [...], because the body has to undergo [...] and [...] to insulin.
A: diabetes; rapid catchup growth; desensitizes

Q: Functional Anatomy of Adrenal Gland
- Zona [...]: Releases [...].
A: glomerulosa; aldosterone

Q: Functional Anatomy of Adrenal Gland
- Zona [...]: Releases [...].
A: fasciculata; cortisol

Q: Functional Anatomy of Adrenal Gland
- Zona [...]: Releases [...].
A: reticularis; sex steroids

Q: Functional Anatomy of Adrenal Gland
- The [...] is the source of catecholamines, and controlled by [...]
A: medulla; direct innervation

Adrenal Steroidogenesis
- All steroids are derived from cholesterol which enters the mitochondria.
- Enzymes involved are CYP enzymes.
- Progesterone is the presursor steroid hormone.

HP-Adrenal Axis
- CRH promotes the release of ACTH which causes a release of Cortisol.
- Cortisol functions to increase blood glucose, through inhibiting GLUT4, gluconeogenesis and muscle breakdown.

Adrenal Steroidogenesis
- ACTH binding increases cAMP and causes the formation of CEH, which promotes STAR.
- Together, these work to produce more cholesterol and also helps transport into the mitochondria

Q: Cortisol Transport
- Primarily carried by [...] protein, but also can be bound to albumin.
- Metabolized in the [...].
- Excreted in the [...]
A: CBG; liver; urine

Q: Cortisol Release
- ACTH and Cortisol release occur both in an [...] pattern and [...]
A: ultradian; diurnal

Cortisol
- Increases protein catabolism, AA uptake by the liver and gluconeogenesis.
- Increases lipid hydrolysis.
- Thinning of skin and connective tissue.

Q: Cortisol also has [...] and [...] properties (which is why you get sick).
A: anti-inflammatory; anti-immune

Cushings disease
- An example of hypercortisolism, causes redistrubution of fat around the body, a thinning of the arms and legs and loose skin.

Q: HSD2 Impairment
- [...] HSD2 in the placenta is correlated to [...] babies
A: Reduced; smaller

Q: Aldosterone
- Higher synthesis when [...] is low and [...] high
A: [Na]; [K]

Aldosterone
- Renal HSD-2 is responsible for converting cortisol into cortisone, so there is no competitive binding to the mineralocorticoid receptor.

Catecholamines
- Primarily epinephrine and norepinephrine.
- Respond more to acute stress, release determined by AP frequency.

Q: Catecholamines
- The [...] nerve is responsible for increasing epinephrine and norepinephrine release.
A: splanchic

Q: The [...] and [...] contain [...] epithelial cells, which is different than the rest of the GI.
A: esophagus; rectum; stratified

Q: The [...], [...] and [...] are made up of 4 layers of cells.
A: stomach; small intestine; large intestine

The four layers of the stomach are the mucosa, submucosa, muscularis externa and serosa

Q: The [...] layer of the GI acts as a [...] layer.
A: serosa; protective

Q: The submucosa acts as a [...] between the [...] and [...].
A: connective layer; mucosa; msucularis externa

Q: There are [...] vessels all throughout the tissue of the GI
A: blood/lymph

Enteric Nervous System
- Located in the submucosa and muscularis externa layers.
- Innervated by the SNS and PNS but can operate autonomously

Q: Enteric Nervous System
- Functions to produce motility patterns that [...] food in the stomach and [...] food in the intestines.
A: pulverise; propel

Mouth
- There is no absorption which occurs here (except glucose).
- Saliva is produced by the parotid, sublingual and submandibular glands.

Q: Mouth
- The [...] gland is composed of [...] cells and secretes a solution high in [...].
A: parotid; serous acinar; amylase

Q: Mouth
- The [...] gland is composed of [...] cells and secretes a solution high in [...].
A: sublingual; mucus; mucus

Q: Mouth
- The [...] gland is composed of [...] cells.
A: submandibular; mucus and acinar

Q: Mouth
- Lingual [...] is secreted a lot at birth, but decreases with age.
A: lipase

Mouth
- Acinar cells secrete macromolecules by exocytosis, Cl and bicarbonate by protein mediated transport and Na+ and H20 via paracellular tranport.

Mouth
- Ductal cells modify saliva based on the rate of saliva flow.
- If flow is slow, Na and Cl levels are decreased and bicarbonate and K+ levels are increased.

Saliva
- Cl is important to amylase, which breaks down starch.
- Lysozyme breaks down bacteria
- PO4 and bicarbonate are buffers to protect the enamel.
- Immunoglobulin A breaks down viruses

Q: Saliva
- Mucus helps [...] the food.
A: soften

Enteric Nervous System
- Sensory neurons in the submucosal plexus can cause short reflexes which involve increasing motility or secretions in response to stretch or the presence of AA/proteins and a high osmolarity.

Q: Enteric Nervous System
- [...] reflexes involve the CNS and involve either [...] stimuli (engage the [...] reflexes) or stimuli from the GI.
A: Long; external; cephalic

Q: [...] of Carbohydrates are absorbed
A: 100%

Q: [...] of Proteins are absorbed in the GI
A: 98%

Q: [...] of Fats are absorbed in the GI
A: 95-98%

Q: Starch must be broken down into [...] to be absorbed
A: monosaccharides

Q: Triglycerides must be broken down into [...] to be absorbed
A: fatty acids

Q: Most chemical digestion occurs in the [...]
A: small intestine

Q: All absorption occurs in the [...], although some [...] can be absorbed in the [...]
A: small intestine; glucose; mouth

Q: The digestive tract can release hormones into the [...]!
- It is technically a [...] gland.
A: bloodstream; endocrine

Q: [...] are the name for the [...]-layer epithelial cells in the small intestine.
A: Enterocytes; 1

Q: The epithelial cells in the GI are also [...] or [...], except in the small intestines where they are absorptive.
A: endocrine; exocrine

Q: [...] cells in the GI protect us from microbes.
A: Immune

Q: The stomach has a third layer of muscle called [...] muscle.
A: oblique

Q: The sound that comes form the stomach is called [...], and is caused by [...]
A: borborygmus; moving gases

Q: The [...] gland is stimulated when you eat food, to generate saliva.
A: parotid

Q: The [...] controls transfer from the mouth to the esophagus.
- Dysfunction might lead to food going up [...]
A: upper esophogeal sphincter; nose

Q: The [...] controls transfer from the esophagus to the stomach.
- Dysfunction might lead to[...]
A: lower esophogeal sphincter; acid reflux

Q: The [...] controls transfer from the stomach to the small intestines.
- Stomach is responsible for [...] food
A: pyloric spincter; pulverising/liquifying

Q: The [...] controls transfer from the pancreas to the small intestines.
- [...] and other releases
A: spincter of oddi; Bile

Q: The [...] controls transfer from the small intestine to the large intestines.
A: illeoceceal valve

Q: The [...] control transfer from the large intestine to the outside.
- The [...] can be controlled once one is potty trained.
A: internal/external anal spincters; external anal spincter

Xerostomia
- Insufficient production of saliva.
- Symptoms include; loss of taste (food is not solubilized), infections (no lysozymes) and difficulty swallowing.
Other symptoms include depression and cavities (no buffer).

Q: Xerostomia
- Some people have better [...] in their saliva, so their [...] are more protected.
A: proteins; teeth

Q: Xerostomia
- Causes include [...], radiation, [...] diseases such as shogrins.
A: drugs; autoimmune

Functions of ENS
1) Control of motility.
2) Regulation of local blood flow
3) Regulation of exocrine secretions.
4) Interactions with the CNS to either start or stop eating.

Functions of ENS
5) Endocrine functions of the submucosal plexus.
6) Entero-enteric reflexes.
- Eg. Gastro-ileal reflex: When food enters the stomach, Illeosecal valve opens to empty the small intestines
- Eg. Babies have an additional reflex where when food enters their stomach, they have to poo

Functions of ENS
7) Defense mechanisms
- Vomiting and diahhrea, or both depending on the pathogen.
- You can actually to some degree control vomitting, but not fully. It is also vile because the fluid comes up from the small intestines.

Q: [...] causes both diahhrea and vomiting.
A: Malaria

Q: There is no [...] regulation of saliva production, only minor adjustments.
A: hormonal

Q: Salivary Production
- PNS activation stimulates activation of [...] receptor, increasing [...] and thus resulting in an [...] in fluid secretion.
A: M3; IP3; increase

Q: Salivary Production
- SNS activation stimulates activation of [...] receptor, increasing [...] and thus resulting in an increase in [...] secretion (in addition to saliva).
A: b; cAMP; mucus/enzyme

Q: [...], also known as chewing, is the mechanical manipulation of food into a smoothened
lump which is called the [...]. Although not necessary for proper [...].
A: Mastication; bolus; nutrient absorption

Q: [...] is not activated until it reaches the stomach.
A: Lingual lipase

Q: Once food hits the [...], swallowing is automatic.
A: pharynx

Q: Secondary peristalsis is initiated if [...]
A: food is lodged in esphagus

Q: Stomach
The stomach acts as a [...] for food before it enters the intestines to be absorbed. The upper portion of the stomach that first receives the bolus is called the [...].
A: reservoir; fundus

Q: Stomach
Stretching is called [...]. Once the bolus is pushed to the more distal regions of the stomach it starts to be liquefied by coordinated [...] contractions for mechanical breakdown.
A: receptive relaxation; muscular

Stomach
The gastric glands of stomach contain both exocrine and endocrine cells, while the epithelial cells at the top of gland and on the rugae folds are mucus neck cells which secrete mucus and HCO3.

Stomach (EXOCRINE)
- The HCl secreting cells are called parietal cells, which also secrete intrinsic factor, an important protein that aids in vitamin B12 absorption in the intestine.
- Chief cells secrete the enzyme gastric lipase and also pepsinogen.
- Mucus cells secrete mucus.

Q: Stomach
The bolus becomes known as [...] when it is digested further.
- Vigorous mixing/ mechanical digestion occurs, pushing fluid towards the [...], some of which escapes through the process known as [...]
A: chyme; pyloric sphinter; gastric emptying

Q: Stomach
Acid gastric juice inactivates [...] and activates [...]
A: salivary amylase; lingual lipase

Q: Stomach
Pepsinogen is cleaved in the acidic env. to become [...], which degrades proteins.
A: pepsin

Q: Stomach
Only a small amount of chyme [...] at any one time.
A: leaves

Q: Salivary Composition
- High flow rate means that saliva is closer to [...].
A: isotonic

Q: Salivary Composition
- The duct mainly absorbs [...], so slower flow has less [...]
A: na; na

Q: Salivary Composition
- Enhancement of [...] and [...] at low flow rates.
A: K; bicarbonate

Q: Salivary Composition
- The [...] gland(s) is/are controlled by [...] nerve (PNS) which pushes for [...] saliva.
A: parotid; CIX; watery

Q: Salivary Composition
- The [...] gland(s) is/are controlled by [...] nerve (SNS) which pushes for [...] saliva.
A: submandibular/sublingual; CVII; mucus

Q: Salivary Composition
- [...], salivary secretions and myoepithelial [...] are all controlled by neurons.
A: Blood flow; contractions

Pyrloric Steanosis
- Pyloric spinchter does not open (genetic), so the baby loses weight, since it cannot absorb food.
- Solved using surgery, to loosen the muscle.

Q: Esophagus
- The esophagus is not a [...] route, there is a little [...] for the heart, where something can get stuck.
A: straight; notch

Q: Esophagus
- Secondary peristalsis is typically quite [...]
A: painful

Q: Esophagus
- Food is primarily chewed so it can be [...]
A: swallowed

Parietal Cells
- The H2O found inside of parietal cell combines
with carbon dioxide to quickly form
hydrogen ions (H+) and HCO3.
- H+ is
pumped into the lumen of the stomach by the
H+-K+-ATPase in exchange for K+.
- K+ is
provided back to the stomach lumen by an
apical K+ leak channel.

Parietal Cells
- Cl follows the electrical gradient created by H+ by moving, through open apical Cl- channels.
- The net result is secretion of HCl by the parietal cells.
- To prevent the increase in cytoplasmic pH through the loss of H+, equal amounts of HCO3 - must be removed from the parietal cell across the basolateral membrane by the HCO3 - -Cl- exchanger.
- Blood near the stomach is more alkaline when digestion is occuring.

Gastric Acid Secretion
- G cells are stimulated to release gastrin into the blood due to the presence of partially digested proteins, or vagus nerve activation which releases gastrin releasing peptide.
- The vagal nerve activation occurs either from stomach distention or thinking about food.
- Gastrin activates parietal cells directly by binding to the receptor, CCKB initiating the release of Ca2+
- Gastrin can also activate histamine release from ECL cells.

Gastric Acid Secretion
- Enterochromaffinlike cells release the paracrine secretion histamine, in response to gastrin or Ach.
- Parietal cells express the H2 subtype, which is a G-protein coupled receptor that stimulates an increase in intracellular cAMP.

Gastric Acid Secretion
- The vagus nerve can be activated by thinking about food, or a short loop reflex within the GI can be activated by the actual presence of food.
- Acetylcholine release onto parietal cells stimulates the activation of the (M3) receptor, which increases intracellular Ca2+.

Acid Secretion
- There are also several signals that inhibit acid release from the parietal cells. These include somatostatin, released by D cells.
- Somatostatin binds to its receptor (SSTR2) on ECL cells to inhibit histamine release, act on parietal cells or act on G cells.
- CCK, H+ and secretin all inc somatostatin release.

Pepsinogen Activation
-Once in the lumen of the stomach, the lower pH causes pepsinogen to cleave itself, producing a smaller protein which is the enzyme pepsin.
- Pepsin can also cleave pepsinogen.

Q: Some compounds such as [...] can be absorbed through the stomach.
A: alcohol

Q: The motility patterns which digest the bolus are [...], propulsion and [...] into 1 mm ppt (chyme).
A: grinding; retropropulsion

In the fasted state, a Migrating Motility complex (motility pattern) occurs in the stomach and small intestines.
- Activated by interstitial cells of cajal and causes the pyloric sphincter to open widely, this is what causes the gas movement which causes boborygmus.
- Eat something to stop it.

Chemical Digestion in Stomach
- Salivary amylase is inactivated (no carb metabolism)
- Lingual lipase is activated (fat metabolism)
- Gastric lipase is secreted (fat metabolism)
- Pepsinogen is secreted (protein metabolism)

Q: Importance of Stomach Acid
- [...] proteins, killing [...] are both very important.
A: Denaturing; bacteria

Q: Parietal Cell
- When parietal cells are activated, the apical [...] is increased drastically, to allow for more secretion.
A: surface area

Q: Parietal Cell
- [...] is the increase in HCO3- being released into the blood after a meal.
A: Alkaline tide

Gastric Acid Secretion
- Synergistic release if gastrin, histamine and Ach are all bound.

Ulcers
- If the mucus layer is gone, the acid will harm the epithelial cells and cause ulcers.
- Disruption can occur from bacteria/H.pylori or NSAIDs
- Prevent ulcers by inhibiting H/K ATPase

Small Intestines
- The first portion of the small intestine, the duodenum, is where secretions from the pancreas, liver and gall bladder combine (through the bile duct).
- The secretions from the pancreas in particular are the only secretions in the entire body which are absolutely necessary for digestion!

Small Intestines
- The duodenum wall has villi to increase surface area to improve chemical digestion but to also aid in some nutrient absorption.
- The jejunum is the next segment of the small intestine and it has many villi to aid in maximal nutrient absorption. On the absorptive cells there are microvilli
- The ileum is the longest segment of the small intestine and although it has villi for increased surface area, it mainly functions to absorb any missed nutrients, but also is the only part of the intestines able to absorb vitamin B12 and bile.

Q: Epithelial Cells of the Small Intestine
- The epithelial cells in the [...] layer of the small intestine participate in final macronutrient absorption.
A: mucosa

Q: Epithelial Cells of the Small Intestine
- [...] cells secrete mucus to aid in lubrication.
A: Goblet

Q: Epithelial Cells of the Small Intestine
- [...] cells secrete a watery HCO3 solution to neutralize acid.
A: Intestinal gland

Q: Epithelial Cells of the Small Intestine
- The membrane of absorption cells are called the [...].
A: brushed border

Q: Endothelial Cells of the Small Intestine
- [...] cells secrete the hormone [...] in response to a low pH of the lumen.
A: S; secretin

Endothelial Cells of the Small Intestine
- The hormone CCK is released from CCK cells in response to macronutrients in the lumen of the digestive tract, particularly lipids and proteins.

Q: Endothelial Cells of the Small Intestine
- [...] cells secrete the hormone [...] in response mostly to glucose in the intestine.
A: K; glucose insulinotropic peptide (GIP)

Q: Microvilli
- Embedded within these apical membranes of enterocytes are several digestive enzymes called [...] enzymes.
-These brush border enzymes are conveniently placed as they cause the production of the [...] units.
- For example, the disaccharide lactose is not absorbable, but due to the brush border enzyme [...], lactose is broken down into the monosaccharide’s glucose and galactose.
A: brush border; absorbable; lactase

Motility in the Small Intestine
- Specialized mixing contractions occur in the small intestine that function to mix chyme with the digestive juices that are secreted into the small intestine.
- Localized mixing contractions, aka segmentations that also function to increase the interactions of the food particles with the absorptive cells in the intestinal mucosa.
- Segmentations are more rapid in the duodenum as compared to the ileum.
- High fat chyme will be more vigorously mixed via segmentations to maximize chemical digestion and therefore promote maximal absorption.

Q: Epithelial Cells of the Small Intestine
- [...] cells secrete lysozyme.
A: Paneth

Large Intestine
- Functions to finish the process of absorption, primarily water.
- Haustra assist in the process, and their "churning" increases exposure of the chyme to the mucosal membrane.
- Chyme spends much more time here than in the small intestines, which is part of the reason there is more bacteria here than anywhere else.
- Peristalsis can be "normal" or vigorous (mass peristalsis: for pooping).

Large Intestine
- Colonic bacteria function to release vitamins such as B and K.
- Fermentation of cellulose and lactose.
- Digestion of remaining peptides.
- Decomposition of conjugated bilirubin
- Produce gases called flatus, such as hydrogen sulfide.

Q: Pancreas
- Ductal cells release [...] and [...] into the mixture secreted by [...] cells.
A: H2O; HCO3; acinar

Pancreas
- Most enzymes secreted by acinar cells are zymogens.
- Trypsinogen is activated due to the action of enterokinase in the small intestines.
- Once activated, typsin activates chymotrypsinogen and procarboxypeptidase.

Q: Pancreas
- An interesting [...] secreted by acinar cells is [...], which in its activated form functions to [...].
A: coenzyme; procolipase; help pancreatic lipase

Pancreas
- Unlike the salivary glands, the acinar cells in the pancreas secrete a homogenous mixtures, it is only the ratio between zymogens and enzymes from all cells which can change.
- CCK can stimulate secretion by acinar cells, and secretin stimulates secretion by ductal cells, in addition to vagal stimulation of both.

Q: Brushed Border Enzymes
1. [...]: Digests lactose into glucose and galactose.
2. [...]: Digests sucrose into glucose and fructose.
3. [...]: Digests maltose into glucose and glucose.
A: Lactase; Sucrase; Maltase

Brushed Border Enzymes
4. Alpha-dextrinase: Digests alpha-limit dextrins from amylopectins, which is the branched form of starch.
5. Aminopeptidase: Digests the amino terminal from a polypeptide.
6. Dipeptidase: Digests dipeptides into two amino acids.
7. Nucleosidase: Digests nucleosides.

Q: Lactose intolerance occurs from a genetic loss of [...], if lactose is left undigested, it causes problems due to the [...] in the [...]
A: lactase; bacteria; large intestine

Q: The three motility forms in the small intestines are [...], [...], and [...].
A: segmentation; peristalsis; migrating motility complex

Vomiting
- Initiated through the vomiting center.
- Powerful contractions all the way from the illeocecal valve upwards (all valves above it open), contraction of abdominal muscles.
- Glottis remains closed.

Q: Vomiting
- Is NOT considered [...]
A: reverse peristalsis

Q: Vomiting
- Higher centers trigger the vomiting centre through stimuli such as [...]
A: pain, sights

Q: Vomiting
- Chemoreceptors trigger the vomiting centre through stimuli such as [2 stimuli], this is not easy to [...], although the response to [...] can be repressed somewhat.
A: drugs, hormones; repress; hormones

Q: Vomiting
- Gastric mucose trigger the vomiting centre through stimuli such as [...], this is not [...].
A: microbe irritants; repressible

Q: Vomiting
- Pharyngeal stimulation triggers the vomiting centre through the [...] solitarius.
A: nucleus tractus

Q: Accessory GI Organs
- Dont come into contact with [...]
A: food

Pancreas
- Acinar cells secrete mainly pancreatic amylase and pancreatic lipase, which both function better in an alkaline pH.
- Also secrete trypsinogen, chymotrypsinogen, procarboxypeptidase, proelastase, procolipase, ribonuclease and deoxyribonuclease.

Gallbladder
- The gallbladder is connected to the liver through the cystic duct, which leaves the gallbladder and joins to the common hepatic duct, forming the common bile duct.
- The function of the gallbladder is to store and concentrate bile (made in the liver) until it is needed.
- Gallbladder emptying is due mostly to hormonal activation causing gallbladder contraction and relaxation of the sphincter of Oddi.

Gallbladder
- Removal of the gallbladder is necessary if an individual has had gallstones regularly.
- Gallbladder removal will prevent any future gallstone attacks as there is no longer a place for bile to concentrate.
- Gallbladder attacks usually follow a high fat meal.
- CCK is released strongly in response to the presence of fats in the intestine, the gallbladder releases bile.
---> Thus, a good treatment for gallstones is a low fat diet or a cholecystectomy.
- Gallstones lodge in either the cystic duct or the common bile duct.

Liver
- Two blood vessels bring blood to the liver; one is the hepatic artery carrying oxygenated blood, the other the hepatic portal vein that brings nutrient rich blood coming from the gastrointestinal tract.
- Within the liver, these vessels pool their contents together into permeable capillaries called sinusoids, which are very leaky capillaries, meaning everything but RBC and WBC can be taken up by the hepatocytes.

Q: Liver
- Cells of the liver can then process the contents of the blood before it exits the liver via the [...].
A: hepatic vein

Liver
- The liver lobule is the functional unit of the liver that is organized in a hexagonal shape with a triad of vessels at each hexagon angle and a vein or hepatic venule in the centre.
- The portal triad is made up of branches of the hepatic portal vein, hepatic artery and a bile duct.

Liver
- Within a liver lobule, hepatocytes are organized into a single plate of cells called hepatic laminae.
- Another hepatocyte function is to produce and secrete bile salts, which aids in the digestion and absorption of lipids.
- Bile solution, as well as waste products are secreted into bile canaliculus.
- These small ducts form larger structures until they eventually merge into the right and left hepatic duct and then into the common hepatic duct.

Liver
- Hepatocytes are unique because they are considered multipolar.
- The hepatocyte membrane that faces a sinusoid is called a basolateral or sinusoidal membrane.
- The apical membrane is found between hepatocytes and is the locale of the bile canaliculus. The portion of the membrane that forms this channel also has microvilli to increase surface area.
- Any membrane by the canaliculi is called the canicular membrane. Anything that is to be excreted/secreted is transported across this membrane.

Components of Bile Solution
- Bile is a complex solution that aids in the metabolism of lipids (detergent) but also functions as a vehicle to excrete waste products.
- Within the mixture of bile are the main component, bile salts as well as phospholipids, cholesterol, other proteins, waste products, bicarbonate, and H2O.
- Bile salts are made from cholesterol as bile acids. Prior to secretion, most bile acids are modified by the addition of a side group such as the amino acid glycine, to produce bile salts, which are less toxic and more amphipathic.

Bile Salt Production and Secretion
- The bile solution containing bile salts is modified as it travels through the bile ducts by cholangiocytes (secrete water and bicarbonate), the cells that form the bile duct.
- The amount of bile salts produced by hepatocytes is controlled by how much bile salts are returned to the liver via the hepatic portal vein.
- When there is an increased level of bile salts in the portal blood, hepatocytes will increase both production and secretion of bile. Therefore, bile release increases as digestion and absorption occurs.

Q: Bile Salt Production and Secretion
- Unlike enzymes, bile salts need to be available in [...] amounts to accomplish the task of solubilizing lipids.
- Like the pancreas, both [...] and [...] inputs regulate bile production and secretion by the liver as well as release of bile from the gallbladder.
A: large; neural; hormonal

Bilirubin Metabolism
- As red blood cells (RBCs) are removed from the body, haemoglobin is metabolized to produce the iron containing substance called haem and globin (non-toxic, amino acids).
- Organs, such as the spleen, produce the toxic substance bilirubin from haem.
- Bilirubin is carried by albumin to the liver, and conjugated so it may be secreted in the bile.
- Once in the large intestine, bacteria metabolize some of the conjugated bilirubin into urobilinogen.
- Most conjugated bilirubin and urobilinogen is excreted from the large intestine but some urobilinogen can be absorbed and transported to the kidney for further metabolism and then excretion.

Bilirubin Metabolism
- In the blood, if total levels of bilirubin rise too much, called hyperbilirubinemia, in either conjugated or unconjugated bilirubin, jaundice can occur.
- If there is an obstruction of the ducts, there is an increase in conjugated bilirubin in the blood in particular.
--> Most likely in the common bile duct, NOT in the cystic duct.
- Other causes incl inc. RBC destruction and liver steatosis, which result in increases in unconjugated bilirubin.

Liver
1) Synthesizes bile
2) Detoxifies the blood
3) produces essential proteins (albumin, clotting factors)
4) Metabolism of nutrients
5) Immune function (kupffer cells)

Q: Cholesterol issues are mainly due to [...] dysfunction, not diet.
A: liver

Q: When we eat a meal, our entire supply of bile salt is secreted and reabsorbed at least [...]x.
A: 2

Bile Salt Production and Secretion
- CCK stimulates gallbladder contraction and relaxation of the sphincter of Oddi. CCK also stimulates the secretion of bile salts from hepatocytes.
- Secretin stimulates H2O and Bicarbonate release from cholangiocytes

Bilirubin
- Carried across sinusoidal membrane by OATP1B to be conjugated with glucuronic acid in the hepatocyte.
- Taken out of the hepatocyte by MRP2 transporter.
- A very small amount goes into the blood using MRP3.

Cephalic Phase
- The taste of food or even just the thought of it is sufficient to stimulate the cephalic phase.
- Higher order neural centres in the cerebral cortex and/or the feeding centre in the hypothalamus are activated which then activate regions in the medulla oblongata such as the nucleus tractus solitarii (NTS).
- This then activates the facial and glossopharyngeal nerves as well as the vagus nerve. The response to this neural activation is increased salivary secretions, increased acid secretion and increased motility of the stomach.

Gastric Phase
- Once food has entered the stomach, the gastric phase is initiated.
- Stretch of the stomach is detected.
- If the pH of the stomach contents increases, usually caused by the presence of peptides, this is detected by chemoreceptors and also serves as a signal for the gastric phase.
- Peptides within the stomach also serve as a stimulus for G cells to secrete gastrin into the blood stream.
- Response is acid secretion from Parietal cells, as well as inc. motility and gastric emptying.

Gastrin functions to increase histamine and acid release, as well as promoting motilty and pyloric opening.

Intestinal Phase (Strongest control)
- Once chyme has begun to enter the duodenum, the
intestinal phase is initiated.
- The detection of chyme is by distension of the intestinal wall (stretch receptors), presence of acid and
partially digested macronutrients (chemoreceptors).
- The enterogastric reflex is initiated by the
duodenal stretch. In this reflex, the medulla oblongata inhibits the parasympathetic pathway but
activates the sympathetic innervation to the stomach.
- The result is a decline in gastric secretion as well
as a decrease in gastric emptying.
- In addition to the previously mentioned actions of CCK, it has also been shown that CCK can
increase the closure of the pylorus.

Q: Regulation of Gastric Emptying
- The intestinal phase [...] gastric emptying in order to allow for proper digestion and absorption of nutrients.
- The [...] and volume of chyme will affect the rate of gastric emptying partially through stretching in the stomach, and chemoreceptors that detect nutrient density in both the stomach and small intestine.
A: discourages; composition

Q: Nutrient Absorption
- Complex carbohydrates include the polymers [...], glycogen and [...].
- The enzyme [...] breaks long glucose polymers such as starch or glycogen into smaller glucose chains and the disaccharide maltose.
A: starch; cellulose; amylase

Q: Carbohydrate Enzyme Mechanisms
Starch is a mixture of linear and branched glucose polymers.
- Amylase digests the [...] portions of starch/glycogen, but the glucose linkages of branched polymers cannot be digested by that enzyme.
- [...] are capable of breaking these branches of [branched part of the sugar] to produce linear smaller polymers.
A: linear; Alpha-limit dextrinases; amylopectin
Extra: amylas

Q: Bilirubin Metabolism
-  Baby jaundice is because the biliary [...] (bile caniculi) is not fully formed.
A: tree

Q: Bilirubin Metabolism
-  Baby jaundice is because the biliary [...] (bile caniculi) is not fully formed.
- Should be placed undersunlight to [...] the bilirubin, so it can be excreted through the [...].
A: tree; solubleize; urine

Q: Gastric Emptying
- Orange juice empties [...] than water.
A: slower

Q: Gastric Emptying
- In humans, alcohol [...] gastric emptying.
A: slows

Q: Gastric Emptying
- Food eventually [...] gastric emptying.
- High protein meals empty the [...].
- High fat meals empty the stomach the [...].
A: increases; fastest; slowest

Q: Gastric Emptying
Drinking alcohol alone makes you more drunk because it is degraded by [...] in the stomach, so if it spends more time in the [...] due to a high [...] meal, you will get less drunk.
A: alcohol dehydrogenase; stomach; fat

Q: Inhibitors of Gastric Emptying
- [...] reflex.
- [...] hormone.
- Calorically [...] meals.
A: Enterogastric; CCK; dense

Q: Protein rich meals empty faster than fat rich meals, because they promote the release of [...]
A: gastrin

Q: GIP [...] the opening of the pyloric sphincter.
A: inhibits

Q: Gastroparesis: Disorders which cause [...], can be caused by [...] from diabetes.
- Avoid diets high in [...]
A: delayed gastric emptying; neuropathy; fat

Q: Carbohydrate Digestion
- There are a lot of [...] added to the brush border carb enzymes, to protect them from [...].
A: sugars; proteases

Q: Carbohydrate Digestion
- After a meal, our body has to replenish all of the [...] enzymes!
A: brush border

Q: If fructose is not sufficiently absorbed (GLUT5 saturation), symptoms similar to [...] intolerance occur.
A: lactose

Carbohydrate Absorption
-  Glucose and galactose can be moved from the
lumen into the absorptive cells by a Na+ symporter on the apical membrane.
- Also, on the apical membrane, fructose is absorbed by a fructose uniporter, called Glut5.
- On the basolateral membrane, {{cq::Glut5}} is also expressed to assist in the movement of fructose into the nearby blood vessels.
- The glucose uniporter, Glut2, can move either glucose or
galactose or fructose across the basolateral
membrane.

Q: Protein Digestion
- [...] are enzymes that recognize either end of a polypeptide.
[...]peptidase recognizes the amino terminus of a polypeptide and will remove whatever amino acid is in the last position of the strand. [...]peptidase removes the last amino acid on the carboxy terminus of a polypeptide.
A: Exopeptidases; Amino; Carboxy

Protein Digestion
- Trypsin is an endopeptidase will cut the carboxy side of either a lysine or an arginine, as long as it isn’t followed by a proline.
- Recognizes many more sequences than pepsin does!

Q: Protein Digestion
Enterokinase is highly specific, recognizing a sequence that is four [...] residues in a row, these can also be substituted for glutamic acid, followed by a [...], where it will cut after that residue.
A: aspartic acid; lysine

Q: Mechanisms of Protein Absorption
- An apical [...] recognizes many amino acids and can move them across the apical membrane.
In reality there are [...] amino acid transporters.
- On the basolateral membrane there is a [...]
A: Na+ symporter; many; Na+ exchanger

Mechanisms of Protein Absorption
- Bi and tripeptides can be absorbed across the apical membrane of enterocytes by an apical H+ symporter called Pept1, may take one or more H+.
- To generate the necessary gradient, a Na/H exchanger is on the apical membrane.
They are then digested in the cell to amino acids, or transported out by a H+ exchanger

Mechanisms of Protein Absorption
- Small peptides can be moved across enterocytes intact in infants. A mechanism of transcytosis is capable of moving some proteins across enterocytes intact.
- Helpful to absorb antibodies from the milk, although placental transport is more important for immunity.
- Can be involved in food allergies if it is active.

Lipid Digestion
- Triglycerides make up the majority of the calories as they are the primary lipid in food sources.
- Chemical digestion of triglycerides serves a major challenge since the enzymes are hydrophilic but lipids are hydrophobic, and will form large fat droplets, so only the surface is interacted with.
- Particularly, in the small intestine, lipid droplets are kept small through the addition of bile salts.

Q: Bile Salts and Fat Digestion
- Since bile solution is secreted into the small intestine, the ampipathic bile salts in the solution then [...] these smaller lipid droplets and keep them from reforming into larger droplets after [...] have slowed down.
- [...] function to break down droplets and move them close to the membrane.
A: cover; segmentations; Segmentations

Bile Salts and Fat Digestion
- Within the now soluble lipid droplets, now called micelles, triglycerides are reduced to diglycerides, thenmonoglycerides.
- Within smaller mixed micelles also contain ingested phospholipids, as well as cholesterol, another important lipid found in our diets.
- Note, there is flux of fatty acids into and out of the micelles.

Fat Absorption
- Although diffusion of both fatty acids and monoglycerides occurs, the rate at which they are absorbed cannot be explained by simple diffusion alone.
flippases and floppases can move fatty acids across the enterocyte membranes.
Other protein carriers also move monoglycerides.

Q: Fat Absorption
- Similarly, although it was once believed that cholesterol was all absorbed by diffusion, we have now found a [...] specific transporter that can be inhibited by a compound called [...].
A: cholesterol; ezetimibe

Q: Fat Absorption
- Absorbed fatty acids and monoglycerides are bound to [...] in the cytosol and transported to the [...]. There, they are recombined into triglycerides once more.
- Combine with [...] from rough ER to form a chlyomicron.
A: carrier proteins; smooth endoplasmic reticulum; apolipoproteins

Q: Fat Absorption
- With the absorbed cholesterol, the triglycerides are packaged into protein coated package called a [...]. These carriers are so large that they have to be packaged into [...] by the Golgi apparatus so that they can be exocytosed across the basolateral membrane.
A: chylomicron; secretory vesicles

Q: Fat Absorption
- The large size of chylomicrons also prevents them from movement into capillaries, so instead, they are absorbed into ymphatic vessels called [...]. Chylomicrons pass through the lymphatic system and finally enter the [...] blood just before it flows into the right side of the heart.
- AVOID the [...] vein.
A: lacteals; venous; hepatic portal

Q: Protein Digestion
- Elastase digests [...] proteins (possibly proline)?
A: elastic

Q: Protein Digestion
- Pepsin likes amino acids with [...] side chains.
A: aromatic

Fat Absorption
- Chylomicrons decrease in size as they pass through the blood by the action of lipases.
- Eventually they reach the liver, which takes the remnant chlyomicron and either stores the triglycerides or repackages them for transport out

Q: The testes mainly function to produce [...] and [...]
A: testosterone; sperm

The epididymus functions as the site of storage and maturation of sperm (up to a month).
- Does this through bathing the sperm in a complex mixture of ions and proteins.
- Maturation involves the acquisition of motility and penetrative skills.

Q: The vas deferens functions as the transport tubule out of the [...] for ejaculation.
- Functions using [...] smooth muscle movements.
- Can be cut to make a male infertile, but not affect [...]
A: epidiymus; perstatalute; libido

Q: Prostate hypertrophy can be an issue because it [...], causing painful [...].
- Measure size using finger in bum, or PSH levels.
A: squeezes the bladder; urination

Seminal vesicles secrete 60% of semen, as an alkaline (protect from acid) composition of fructose (ATP), semenogelin (coagulation) and prostaglandins (smooth muscle contraction of female tubes).

Prostate secretes 25% of semen, as an acidic composition of citric acid (ATP) and PSA (disrupts coagulation/inc. motility).

Q: [...] secretes 5% of semen, as an [...] composition of [...] (lubrication).
A: Bulbourethral gland; alkaline; mucus

Q: The Rete testis functions to [...].
A: collect sperm from seminiferous tubules

Q: The Cauda (tail) of the epididymis functions to [...].
A: concentrate sperm

Q: The Corpus (head) of the epididymis functions to produce [...] (highly potent).
A: DHT

Q: [...] cells of the testes sit outside the tubule and produce [...], which can be quickly transported into the [...] beside them.
A: Leydig; testosterone; capillaries

Sertoli (nurse) cells of the testes rely on metabolites from leydig cells and function to nourish and support developing germ cells.
- Release fluids to push germ cells into lumen.

Q: Spermatozoa leave the testies through small tubes called [...]
A: efferent ductules

Spermatogenesis
- Begins with a spermatogonium (46 chromosomes), which can form another spermatogonium and a primary spermatocyte (46). This occurs before the blood-testes barrier
- The primary spermatocyte then can become 2 secondary spermatocytes (meiosis- both 23 diploid).
This second step must occur within the BTB, so that the cells are not attacked by the immune system.

Q: Spermatogenesis
- There are [...] gametes produced from each primary spermatocyte.
A: 4

Spermiogenesis
- The head (acrosome) contains the genetic material and enzymes (to break the zona pellucida).
- The midpiece contains the mitochondria.
- Spermatotid become spermatozoa
- Cytoplasm and organelles are removed.

Q: Spermatogenesis takes about [...] days to complete and occurs at about [...]/sec.
- Staggered production, to ensure a [...] supply.
A: 64; 1500; fresh

Q: The [...] is the membrane between the leydig cells and the spermatogonium.
A: basal membrane

Q: The [...] s the membrane between the leydig cells and the spermatogonium.
A: basal membrane

Q: Modern sperm is much less [...] than in the past as well as overall [...] being much lower.
- Partially due to abuse of [...].
A: motile; sperm counts; drugs and alcohol

Q: The chance of sperm motility being clinically abnormal is
- [...] at age 22.
- 40% at age 30
- 60% at age 40
- [...] at age 60
A: 25%; 85%

Q: Male reproductive fertility peaks at the age of [...]
A: 18

Q: - Obesity is linked to decreases in seminal [...], and sperm [...].
- Paternal obesity can impair [...] in female offspring.
A: volume; motility; insulin sensitivity

Q: [...] issues and decreases in sperm [...] increase as the age of the father increases.
- Spermatogonia have undergone way more [...]
A: Genetic; motility; divisions

Steroidogenesis (occurs in the Leydig cells in males)
- STAR is responsible for regulating cholesterol transfer within the mitochondria.
- The first step of steroid synthesis involves cleavage of the side chain of cholesterol, using CYPscc, to produce pregnenolone.
- Both STAR and CYPscc can be controlled by LH

Q: Steroidogenesis (occurs in the [...] cells in males)
- Once pregnenolone is produced (rate limiting step), it then diffuses to the [...], where the rest of the process occurs.
A: Leydig; ER

Q: Steroidogenesis in Males
- LH can also control how much [...] is produced directly, by regulating expression of 17-B hydroxysteroid dehydrogenase (converts [...] to [...]).
A: testosterone; androstenedione; testosterone

Q: Steroidogenesis in Males
- Testosterone can be converted to [...] by 5a-reductase.
- Type 1 5a-reductase is more common in [...], Type 2 is active in [...].
A: DHT; utero; adults

Q: Steroidogenesis in Males
- Testosterone can be converted to [...] by aromatase.
A: estradiol

Gonadotrophin regulation of speramato and steroidogenesis
- LH functions on leydig cells.
- Pulses of GnRH occur every hour (starting after puberty)
High frequency stimulates LH and low frequency stimulates FSH release.
- FSH functions on sertoli cells.
- Alpha subunit binds receptor, and beta subunit confers function.

Q: GnRH release
- Low Frequency Pulses inhibit LH because [...].
- High Frequency Pulses promote LH because [...]
A: activators are not made, so inhibitors bind; activators are made

Q: GnRH release
- Low Frequency Pulses promote FSH because [...].
- High Frequency Pulses inhibit FSH because [...]
A: inhibitors are not made; inhibitors are made

Folliculogenesis
Step 1: Primordial to primary follicle
- Differentiation of pre-granulosa cells (flat) to granulosa cells (cuboidal).
- Development of zona pellucida

Folliculogenesis
Step 2: Primary follicle to secondary follicle
- Increase in the granulosa layer of cells.
- Theca cells begin to appear.
- Need FSH and LH to proceed past this stage.
- Considered the end of the preantral stage.

Folliculogenesis
Secondary Follicle
- Basal lamina is on the surface, surrounded by theca cells (similar to leydig).
- Just inside, you have the granulosa cell layer (similar to sertoli) and then the zona pellucida.
- Antral cavity is filled with secretions (from granulosa cells) and estrogen

Q: Folliculogenesis
- [...] follicle is the largest (final stage before release).
- Full development of [...], need [...] to live.
A: Graafian; antrum; LH/FSH

Q: Folliculogenesis
- [...] follicle is the largest of all graafian follicles and contains the [...] (granulosa cells which are to be released with egg).
A: Dominant Graafian; corona radiata

Q: Steroidogenesis (Females)
- LH functions on the [...] cell to produce [...].
Note: Increase in activity of STAR/CEH etc.
A: theca; androstendione

Q: Steroidogenesis (Females)
- FSH functions on [...] cell to produce [...].
Cell cannot perform beginning steps of steroidogenesis (eg. no [...])
A: granulosa; estrogen; CYP19

Q: Folliculogenesis
- The dominant follicle actually begins growing [...] days before ovulation.
- A small subset (6-12) of follicles grow to be [...] around 20 days before ovulation.
A: 80; antral

Q: Female Cycle Hormones
- LH surge occurs just prior to [...].
- [...] levels drop post ovulation but remain higher than [...]
A: ovulation; LH; FSH

Preparing For Ovulation
- Just before ovulation, LH receptors are inserted into the membrane of granulosa cells, letting them respond to :LH.
- Promotes the synthesis of progesterone and downregulates synthesis of estradiol.

Q: Preparing For Ovulation
- LH surge promotes the completion of [...] as the egg is released.
A: Meiosis I

Q: Preparing For Ovulation (LH)
- LH surge promotes the production of [...] (to make more LDL receptors) and [...] (for angiogenesis).
A: IGF; VEGF

Q: Post Ovulation
- Lutenized granulosa cells produce mainly [...] and a little bit of [...]
A: progesterone; estrogen

Q: Post Ovulation
- Body temperature [...] due to progesterone.
A: rises

Q: Corpus Luteum
- Remnant of follicle.
- [...] rich to provide fuel for the production of [...]
A: Lipid; progesterone

Estrogen and Follicular/Luteal Phases
- Estrogen reduces LH/FSH during the follicular phase as well as the luteal phase.
- Feedfoward effect (inc. LH/FSH, receptors, sensitivity) during ovulation

Q: Estrogen and Follicular/Luteal Phases
- Rise in progesterone prevents successive [...] during ovulation.
A: LH surges

Uterus Lining
- Composed of the endometrium (stratum functionalis and basalis) and the myometrium

Q: Endometrium
- Estrogen promotes [...].
- Progesterone promotes [...]
A: proliferation; secretion

Q: Estrogen is important for [...] for progesterone effects on endometrium.
A: priming

Q: IGF is important in [...] of endometrial growth
A: phase I

Q: Glycogen is important in [...] of endometrial growth
A: phase 2

The Luteal Phase
- Stimulated by LH, the corpus luteum secretes progesterone.
- If fertilization does not occur, corpus luteum fails (dec in progesterone/estrogen) and endometrium degrades.
Followed by a reversal of uterine contraction inhibition and cramps/bleeding begin.

Physiological Effects of Estrogen
- Increases  layering of vaginal epithelium.
- Prepares uterine endometrium for the effects of progesterone by promiting receptor synthesis.
- Stimulates proliferation of spiral arteries.
- Increase in contractions (push sperm) and ciliary activity during ovulation.
- Promotes zona pellucida lysis.
- Female genitalia growth and breasts (duct work).

Physiological Effects of Progesterone
- Decreases contractions (allows egg to move).
- Promotes synthesis of uterine milk to allow for implantation.
- Decreases uptake of calcium in the uterus.
- Promotes mammary alveolar development during pregnancy.

Q: Menopause
- Follicles become less responsive to [...] and die.
- Therefore, a decrease in [...] levels and an increase in [...] (-ve feedback).
- Ovulation/menstruation become irregular and stop
A: LH/FSH; estrogen; LH/FSH

Q: Menopause
- [...] flashes
A: Hot

Q: DHT and Muscle
- Since [...] is in the circulation, it can affect muscle, even though muscle does not have [...]
A: DHT; 5a reductase

Q: Sperm and Egg
- The sperm takes about [...] to travel to the egg.
- The egg takes about [...] days to reach the uterus.
A: 20 minutes; 4

Q: Sperm and Egg
-Find each other using [...] and [...].
A: chemicals; termperatures

Estrogen and Uterus
- Estrogen decreases viscosity (progesterone increases viscosity (to protect)}.
- Promotes contractions.
- Increases glycogen to decrease pH.

Q: Sperm travel
-  Over [...] sperm are in ejaculate, but only a few [...] make it there.
A: 100 million; dozen

Q: Capacitation of sperm (needed for ferilization)
- Completed in the female reproductive tract.
- Removal of [...] (prep for fusion).
- Inc in sperm motility ([...] influx promotes [...] motion and hyperactivity).
A: acrosomal head; calcium/cAMP; whiplash

Capacitation, pH and sperm.
- Promotes intracellular alkilanization (activation)
Increasing HCO3-.
Sperm metabolism.
Sperm motility