Title: Physiology 2130 / Module 13: Endocrine System

Header: What are the major parts (organs) of the endocrine system?

Functions of the Endocrine System:
1. Maitenance of Internal Environment (ex., body temperature, body fluid, volume, osmolality, etc.);
2. Adaptation to Stress;
3. Control of Growth and Metabolism;
4. Control of Reproduction .

Q: The actions of the endocrine system are [...]. It also has [...] effects than the nervous system.
A: slower to take effect; longer lasting
Extra: The effects of the endocrine system are also more widespread throughout the body.

Q: The endocrine system can [...] affect many organs of the body at a distance by secreting chemicals into the blood.
A: indirectly

Q: An [...] is a group of specialized cells that synthesize, store and release hormones into the blood.
A: endocrine gland

Q: [...] are chemicals that are released into the bloodstream and circulate throughout the body.
A: Hormones

Q: Hormones affect [...] by binding to specific receptors.
A: target cells

Q: Target cells can be [...] or [...].
A: stimulated; inhibited

Q: Polarity of hormones determines how it is [...] and [...] on the target cell.
A: carried; acts

Q: Hormones are secreted into the blood in [...] by specific stimuli ([...] or [...]).
A: pulses; neural; blood borne

Q: The amount of hormone secreted will vary depending on the [...] of the stimulus.
A: strength

Q: Hormones are present in [...] concentrations in the blood.
A: very small

Q: Hormones generally act by regulating [...] reactions.
A: pre-existing

Q: Since hydrophobic (lipid soluble) hormones can diffuse through the cell membrane, the receptor will be located in the [...] or the [...] of the target cell.
A: cytoplasm; nucleus
Extra: The hormone/receptor complex will bind to the DNA within the nucleus to alter various activites of the cell (ie. increase or decrease in production of proteins)

Q: Types of Hydrophilic Hormone Receptors:
1. [...]
2. [...]
3. [...]
A: Second Messenger; Tyrosine Kinase; G-Protein

Hormones are removed from the blood by:
1. Metabolic Destruction in blood or by tissue.
2. Excretion by the liver into the bile.
3. Excretion by the kidneys into the urine.

Q: Secretion of most hormones is regulated by [...].
A: negative feedback

Q: The [...] is located at the base of the brain, above the pituitary gland and below the thalamus.
A: hypothalamus

Q: [...] are hormones from the hypothalamus that cause release or inhibition of a hormone from the anterior pituitary gland.
A: Releasing factors

Q: The [...] develops from tissue that forms the roof of the mouth, and is made of endocrine tissue.
A: anterior pituitary
Extra: The endocrine cells in this area secrete pituitary hormones directly into the blood.

Q: The anterior pituitary is regulated by the hypothalamus through the [...].
A: hypothalamic-hypophyseal portal system

Q: The [...] develops from neural tissue at the base of the brain, and contains the axons and nerve terminals of neurons that have cell bodies in the hypothalamus.
A: posterior pituitary

Q: Tract of neurons from the hypothalamus to the posterior pituitary is called the [...].
A: hypothalamic-hypophyseal tract

Q: Neurons can produce [...] which are secreted into the blood by the posterior pituitary.
A: neurohormones
Extra: ie. oxytocin and antidiuretic hormone

Q: The anterior pituitary controls many [...] functions and regulates [...] growth.
A: metabolic; reproductive organ

Header: What does the hormone do?

Q: There are 3 negative feedback loops the hypothalamus uses, the [...] loop, [...] loop and [...] loop.
A: short; long; ultra long

Q: T3= [...]
T4 = [...]
A: triiodothyronine; Thyroxine
Extra: T4 = aka tetraiodothyronine

Q: The [...] surrounds the trachea and lies directly below the larynx.
A: thyroid gland

Components of the Thryoid Gland:
1. Follicles - the functional unit of the gland.
2. Colloid - central region.
3. Epithelial Cells - which surround the central region.
4. Parafollicular cells (aka C-cells) - lie between the functional units.

Q: The main function of the thyroid is to produce [...] and [...] which is nonessential to life.
A: T3; T4,

Q: T3 and T4 are responsible for regulating [...] of the body.
A: basal metabolic rate

Q: Parafollicular cells of the thyroid gland produce [...].
A: calcitonin

Q: Iodine is absorbed from one's [...].
A: diet

Production of T3/T4:
1. Epithelial cells take up tyrosine from circulation;
2. Tyrosine combines with thyroglobulin (a glycoprotein), = tyrosine-thryoglobulin complex;
3. Tyrosine-thyrogobulin complex is secreted into the colloid;
4. Iodine attaches to each tyrosine (1 or 2 molecules per);
5. In colloid, 2 tyrosine molecules join together while attached to thyroglobulin;
6. Depending on number of iodine molecules, will get T3 or T4.

TSH Stimulates the Following Reactions:
1. Trapping + Uptake of iodine;
2. Stimulates endocytosis of thryoglobulin complex into the cell;
3. Enzymatic removal of thyroglobulin in epithelial cells;
4. Secrection of T3 and T4 into the blood.
Extra: TSH = Thyroid Stimulating Hormone

Q: TSH can stimulate the thyroid to grow, this is called [...].
A: hyperplasia

Q: T3 and T4 secretion is regulated by [...] which stops the release of [...].
A: negative feedback loop; TSH

Q: Roughly 90% of the hormones released from the thyroid gland consist of  [...] while about 10% is [...].
A: T4; T3

Q: Most T4 is converted to T3 because T3 is the more [...] molecule.
A: biologically active

Q: BMR is the amount of [...] and [...] that the body is using at rest.
A: oxygen; energy
Extra: That is, the least amount of energy a person will use.

T3 and T4 effect/regulate:
1. BMR;
2. The proper development of nervous system in a fetus;
3. Alertness, responsiveness and emotional state.

Q: Cretinism is due to [...] before or after birth in children, and is characterized by [...] and [...].
A: hypothyroidism; drawfism; mental retardation
Extra: Can be prevented by hormone injections.

Q: Hypothyroidism leading to cretinism can be caused by:
1. Congenital lack of a [...];
2. Inability of a gland to produce T3 or T4 due to a [...];
3. Lack of [...] in the diet.
A: thyroid gland; genetic defect; iodine

Q: [...] is a disease that results in the enlargement of the thyroid gland.
A: Goiter

Q: Causes of Goiter:
1. [...];
2. [...];
3. [...].
A: Insufficent Iodine; Too much TRH; Too much TSH
Extra: TRH = Tyrotropin Releasing Hormone

Q: A [...] can cause excess secretion of TRH and TSH.
A: hypothalamic tumor

Q: Excess [...] is specifcally what causes a thyroid to become enlarged.
A: TSH

Q: [...] regulates calcium levels.
A: Calcitonin

Q: An increase in calcitonin results in a [...] in Ca++.
A: decrease

Q: Parafollicular cells (C cells) make up roughly [...] of thyroid gland in humans.
A: 0.1%

Q: [...] are cells that break down bones into calcium which is released to the blood (bone dissolving cells).
A: Osteoclasts

Q: Calcitonin reduces osteoclast [...] and [...] and it stimulates secretion of calcium into the [...].
A: #; activity; urine

Q: To maintain constant blood calcium levels, calcitonin works with [...].
A: parathyroid hormone (PTH)

Q: Parathyroid glands are on the [...] side of the thyroid.
A: posterior

Q: When blood calcium levels are low, parathyroid glands [...] which increases blood calcium levels.
A: secrete PTH

Q: PTH either [...] the # and activity of osteoclasts OR [...] excretion of calcium in the urine through [...].
A: increases; decreases; reabsoption

Q: Adrenal glands are located on the [...].
A: kidneys

Q: Adrenal glands are made of [...] and [...] tissue.
A: neural; glandular

Q: Adrenal Gland Componets:
1. [...] = composed of neural tissue; is under the control of SYN;
2. [...] = endocrine tissue; is under the control of pituitary hormones.
A: Inner Medulla; Outer Cortex

Q: Adrenal Cortex Layers:
1. [...] - outer, secretes aldosterone (helps to regulate mineral & fluid volume by the kidney);
2. [...] - middle, secretes cortisol (helps in glucose metabolism);
3. [...] - inner, secretes androgens (i.e., sex steroids.
A: Zona Glomerulosa; Zona Fasiculata; Zona Reticularis

Q: Medulla of adrenal gland secretes [...].
A: epinephrine
Extra: aka Adrenaline

Q: There is always cortisol being released into the blood in small amounts, it follows the [...] throughout the day.
A: circadian rhythm

Q: Excess secretion of cortisol results in [...].
A: Cushing's Syndrome

Q: Depression, wasting muscles, thin skin, poor wound healing, easy bruising and fat deposits in the cheeks and abdomen are caused by [...].
A: excess cortisol
Extra: These are symptoms of Cushing's Syndrome.

Q: The pancreas lies parallel and beneath the [...].
A: stomach

Q: The 2 types of tissues that make up the pancreas are: [...] and [...] tissue.
A: endocrine; exocrine

Q: Endocrine tissue of the pancreas contains 1-2 million [...].
A: pancreatic islets
Extra: aka the Islets of Langerhans

Q: Pancreatic islets are [...]mm in diameter and surrond small capillaries.
A: 0.3
Extra: or 0.01 inches

Q: Types of Cells in the Pancreatic Islets:
1. [...] - 25% of islets, secrete glucagon;
2. [...] - 60%, secretes insulin and amylin;
3. [...] - 10%, secretes somatostatin (GIH).
A: Alpha; Beta; Delta
Extra: Somatostatin is aka Growth Inhibiting Hormone

Q: Exocrine tissues of the pancreas consist of [...] and [...].
A: pancreatic acinar cells; ducts

Q: [...] tissues secretes hormones into blood.
[...] tissue secretes chemicals into the digestive tract.
A: Endocrine; Exocrine

Q: Insulin is a protein hormone that causes cells to take up, store and use glucose = [...] of glucose in the blood stream.
A: decrease

Q: [...] is the stored form of glucose.
A: Glycogen

Q: The [...], [...] and [...] respond maximally to insulin.
A: liver; muscles; adipose tissue

Q: [...] is a protein hormone that increases blood glucose concentration.
A: Glucagon

Q: Glucagon is secreted when blood glucose is [...] and when animo acid levels in blood are [...].
A: low; high

Q: Glucagon triggers [...] and [...].
A: glycogenolysis; gluconeogensis

Q: [...] = the breakdown of glycogen into glucose (glycogen is the storage form of glucose).
A: Glycogenolysis

Q: [...] = converts non-carbohydrates into glucose (ie. amino acids or fatty acids)
A: Gluconeogensis
Extra: - Gluco = Glucose
- Neo = New
- Genesis = Formation

Q: Muscles can use [...] as a source of fuel.
A: fatty acids
Extra: Muscle cell membrane is not very permeable to glucose itself; Fatty acids can diffuse right across.

Q: It is believed that the [...] stimulates the release of glucagon.
A: SYN
Extra: Especially during exercise...

Q: Somatostatin is released in the:
1. [...];
2. [...];
3. [...].
A: Digestive Tract; Hypothalamus; Pancreas

Q: Somatostatin is released from the pancreas when:
1. [...];
2. [...];
3. [...].
A: High blood glucose; High amino acids in the blood; Increase in blood born fats
Extra: All are related to the indigestion of food.

Q: The primary function of somatostatin is to reduce secretion of [...] and [...].
A: insulin; glucagon
Extra: Reason why isn't clear. It is believed that it could be to prevent extremely rapid storage of food and trying to make it avaliable to the body for a longer period of time.

Q: Your blood glucose level when you wake up (normally fasted) is [...]mg/100mL.
1 hour after a meal it can be [...]/100mL of blood
A: 80-90; 120-140mg

Q: Glucose is the primary fuel for the [...], [...], and some cells in the [...].
A: brain; retina; gonads

Q: During periods of [...], glucagon stimulates gluconeogensis to maintain blood glucose levels.
A: starvation
Extra: At about 80-90mg/100mL.

Q: [...] - early onset, immune system attacks and damages beta cells leading to lack of insulin production.
[...] - adult onset, cells become resistant to the insulin's usual uptake and storage effects, and beta cells become depleted and release less insulin over time (can get to the point of none).
A: Type I Diabetes; Type II Diabetes

Q: A change in [...] and [...] is usually enough to treat type II diabetes.
A: weight; diet