Title: Phys 3120 / Midterm 1

Permeability: How easily an ion can move through a channel
- Cl is highest, Na is lowest

Q: [...]: [...].
A: Ouabain; Inhibits Na/K ATPase at high conc. by binding to K+ binding spot extracellularly

Q: [...]: [...].
A: Digoxin; Inhibits Na/K ATPase in heart

Q: High solute concentration = [...] water concentration
A: low

Q: Osmotic pressure: [...].
- Higher when there is [...] solute concentraiton.
A: Pressure applied to a solution to prevent osmosis; high

Q: [...]: [...]
A: Hypertonic; Solution is more concentrated than cell, cell shrinks

Q: [...]: [...]
A: Hypotonic; Solution is less concentrated than cell, cell grows

Q: Cystic fibrosis results from [...], so [...] and then the pericilliary fluid is also [...].
A: Cl not being pumped out; the cell draws in Na; drawn in

Q: Water intoxication is called [...]
A: Hyponatremia

Q: Bulk flow is the [...]
A: flow of water and its dissolved substances

Flow out of the plasma is called filtration and flow into the plasma is called reabsorption

Q: [...] is [...]
- Decreases [...].
A: Hydrostatic Pressure of Capillary (Pc); the pressure of filtration of the blood like a hose; along the length of the Capillary

Hydrostatic Pressure of Interstitial Fluid (Pif) is the pressure of reabsorption into the plasma
- -6 in subcutaneous tissue and +6 in encapsulated organs.

Q: [...] is [...]
A: Plasma oncotic pressure (PIp); The pressure of osmosis of plasma proteins

Q: [...] is [...]
A: Interstitial oncotic pressure (PIif); The pressure of osmosis of interstitial proteins

Q: Lympatic system works using [...] as well as [...].
A: smooth muscle pumps; contraction of skeletal muscle

Q: Tissue damage [...] Kf
A: increases

Q: [...]: [...]
A: Equilibrium Potential; The electrical potential (mV inside cell) required to exactly offset the force of the concentration gradient of the ion

“Stimulate” nerve.
Membrane depolarizes.
V.G Na+ channels open quickly (& close quickly).
Lots of Na+ flows into cell.
Action potential is initiated at -55 mV.
Membrane depolarizes rapidly to +45 mV.
K+ V.G channels begin opening, while Na+ V.G channels begin inactivating (en masse).
Gives the rounded peak.
AP never reaches ENa+ of +60 mV.
Eventually, all K+ V.G channels are open, and all Na+ are inactivated.
K+ rushes out of the cell.
Membrane repolarizes (+45 mV to -70 mV).
K+ continues to leave the cell (K+ channels close slowly).
Membrane hyperpolarizes (EK+ = -90 mV).
K+ channels close.
Membrane potential returns to normal (-70 mV), channels return to “resting configuration” ready to fire another AP.

Q: [...]: [...]
A: Tetrodotoxin (TTX); Reversibly blocks Na+ channels

Q: [...]: [...]
A: Grayanotoxin; Reversibly blocks Na+ inactivation

Q: [...]: [...]
A: Tetraethylammonium (TEA); Reversibly blocks K+ channel

Q: [...]: [...]
A: Dendrotoxin; Reversibly blocks K+ channel (mamba)

Q: Note, Na/K pump is [...] for repolarization.
A: not required

Q: [...] refractory period is when there is [...] Na+ conductance.
A: Absolute; no

Q: [...] refractory period is when there is [...] K+ conductance.
A: Relative; high

Q: Sub-threshold potentials are not refractory since [...]
A: not all the Na channels have opened/closed

Q: Size of an AP only changes if you [...]
A: change ion concentrations

Q: Larger diameter axons have [...] resistance and [...] speed.
A: lower; higher

Q: [...] produce myelin sheaths in the [...]
A: Schwann cells; PNS

Q: [...] produce myelin sheaths in the [...]
A: Oligodendrocytes; CNS

Q: Saltatory conduction is when [...]
A: you have AP propagation in a myelinated neuron

Q: Multiple sclerosis is caused by [...].
- Causes [...]
A: immune system attacking myelin sheaths; an inability to move

Alpha potential in alpha motor neuron.
Depolarization of alpha MN terminal.
Voltage gated Ca2+ channels open.
Influx of Ca2+ down its concentration gradient into the cell.
Fusing of Ach vesicles to membrane of MN terminal, results in release of Ach.
Ach is the only neurotransmitter in the neuromuscular junction.
Diffusion of Ach to muscle cell membrane at endplate.
Attachment of 2 molecules of Ach to receptor.
Opening of non-specific cation channels at endplate.
RMP is -90 mV, so Na+ is drawn into the cell. K+ is happy at -90 mV!
Preferential increase in sodium influx into the cell.
Depolarization of muscle cell (endplate potential-EPP)
This is not an action potential! Have to open the voltage-gated channels!
Local current (EPP) opens the voltage gated channels, producing an AP.
APs propagated along the muscle cell membrane, spreading in all directions.
Ach is broken down by acetylcholinesterase (into choline and acetate), which are then recycled by the presynaptic axon terminal.

Q: [...]: [...].
A: Botulism toxin; Blocks release of Ach at NMJ, leading to paralysis

Q: [...]: [...].
A: Nerve Gases; Blocks action of acetylcholinesterase, leading to seizures

Myasthenia Gravis: Autoimmune disease where acetylcholine receptors are blocked
- Can be treated by neostigmine which blocks acetylchlinesterase.

Q: Troponin is composed of [...].
- Functions to [...]
A: Troponin C, Troponin A and Troponin T; bind to calcium then remove tropomyosin from actin's myosin binding sites

Q: Myosin heads bind [...]
A: actin and ATP

Q: [...]: [...]
A: Titin; Protein which holds thick filaments in allignment

Q: [...]: [...]
A: Nebulin; Holds thin actin filaments

Q: Striations are from [...]
A: thick and thin filaments

AP opens Dihydropyridine (DHP) in T-tubule.
Ryanodine Receptor/Calcium channel in SR opens

Q: Muscle contraction is stopped by [...]
A: pumping out calcium into the SR

Q: [...]: [...]
A: Calsequestrin; Binds to calcium in the SR

ATP has 4 functions in muscles
1) Positions myosin head on actin
- When hydrolyzed
2) Causes a powerstroke.
- When released
3)Releases myosin from actin
- When new ATP binds
4) Pumps ca into SR

Q: Slow vs fast twitch depends on [...]
A: ATPase activity of myosin

Q: To sustain a muscle contraction, we can [...]
A: increase AP frequency, increasing ca in muscle tissue

Q: Glial cells function for many different purposes.
These include: [...]
A: supplying backup glucose, removing neurotransmitters/ammonia/K+ etc.

Q: Electrical synapses have very low [...] between the neurons and are [...]
A: resistance; bidirectional

Q: EPSPs [...] the cell and are due to increased permeability to [...]
A: depolarize; Na and K

Q: IPSPs [...] the cell and are due to increased permeability to [...].
- These two ions work hand in hand to reduce the chance of neuronal firing.
A: hyperpolarize; Cl and K

Q: [...] receptors bind to [...] and open a [...] channel
A: AMPA; glutamate; sodium

NMDA receptors bind to glutamate and open a calcium/sodium channel
- Down the line can also result in insertion of more channels, inc. sensitivity, or new channels being produced.

Q: [...] receptors bind to [...] and are [...]
A: G-protein; neuromodulators; metabotropic-dont work via ions

Five Classes of Neurotransmitters
1) Acetylcholine: Responsible for alzheimer's
2) Biogenic Amines:  Dopamine (parkinson's), serotonin
3) Amino Acids: Glutamate and GABA/glycine
4) Neuropeptides: Act as neuromodulators
5) Other: NO (retrograde, steroids).

Q: [...]: [...]
A: Strychnine; Antagonist of glycine, causes convulsions

Q: Long-term potentiation occurs in neurons which [...] and is an [...] in response to the same stimulus
A: can generate AP; increase

Q: Long-term potentiation primarily occurs in cells with [...] receptor
A: NMDA

Q: Long-term potentiation Mechanism
Presynaptic: [...].
Postsynaptic: [...]
A: Increase in calcium entry into cell; Inc. sensitivity, new AMPA channels inserted, AMPA channels synthesized

Q: Presynaptic inhibition/facilitation is [...]
A: decreased calcium influx or increased calcium influx

Q: [...] stimulus of the eye is light
A: Adequate

Q: [...] are EPSPs in sensory receptors.
- Ie, they are [...]
- Begin at [...] in mechanically transducing cells.
A: Generator potentials; graded, non-propagated etc.; node of ranvier

Q: [...] receptors respond [...], and encode via [...]
A: Slowly adapting (tonic); as long as there is a stimulus; population and frequency coding

Q: [...] receptors respond [...], and encode via [...]
A: Rapidly adapting (dynamic); only to changing stimuli; population coding

Q: [...] is a [...] mechanoreceptor.
- [...] slip back if the stimulus is the same.
- If stimulus differs, the onion skin doesn't slip and the ion channel is deformed.
A: Pacinian corpuscle; rapidly adapting; Inner lamellae

Q: Note, rapidly adapting receptors such as pacinians can vary in the AP frequency, but only when the [...] is different.
A: frequency of stimulation

Q: Type [...] receptors have a [...] receptive field.
A: 1; small

Q: Type [...] receptors have a [...] receptive field.
A: 2; large

Q: [...] of a stimulus is signalled by [...]
A: Quality; Specificity of receptor

Q: [...] of a stimulus is signalled by [...]
A: Quantity; Frequency or population coding

Q: Large axons tend to be type [...] and are fast
A: A

Q: Small axons tend to be type [...] and are slow
A: C

Q: A [...] is formed when you sum the AP of different nerves.
- [...] between peaks can tell you which nerve is faulty
A: compound action potential; Latency

Sensory/Axon Physiologists
Aa: Alpha motor neurons & skin afferents
Ab: Skin afferents
Ag: Fusimotor (gamma) neurons
Ad: Fast pain, cold temp
C: Unmyelinated, slow pain, warm temp, crude touch

Motor Physiologists
Ia: Annulo spiral muscle spindle (primary)
Ib: Golgi tendon organ
II: Flower spray from muscle spindle (secondary)
III/IV: Free nerve endings, IV=C

Q: [...] receptive field and [...] innvervation density means high acuity.
A: Small; high

Dorsal (Medial Lemniscal) Column
- High development in primates
- Good for fine touch
- Small receptive fields.
- 1:1 ratio up to somatosensory cortex.
- Fast conduction
- Contralateral, crosses over at brainstem

Spinothalamic Column
- Old system
- Good for pain, crude touch, itch
- Large receptive fields.
- Convergence of modailities during transduction.
- Crosses over at spine

Q: Somatosensory Cortex
Has [...] organization, where [...].
- Order of body parts from lateral-medial :[...]
A: somatotropic; parts important for feeling are overrepresented; Face, fingers, arm, trunk, legs, feet

Q: Somatosensory Cortex
Evidence of organization comes from
[...]
- Can tell us where a seizure or tumour is.
A: leisons, recordings, stimulation and epilepsy

Somatosensory Cortex
Use or experience dependent plasticity: More you use a certain body part, the larger the area dedicated to it becomes.
- Can occur through enroachment into space
or synaptically remove inhibition (remove GABA) or increase Na channels.
- Synaptic works by activating dormant synapses that were alread present.

Somatosensory Cortex
- Cortical columns are modality pure and have a similar receptive field
- 10% of columns come from spinothalamic system and have messy modality

Q: Somatosensory Cortex
Analysis of object properties occurs in the [...]
A: somatosensory cortex

Q: Somatosensory Cortex
Higher order reconstruction occurs in the [...]
A: posterior parietal cortex

Q: Somatosensory Cortex
A lesion in the right posterior parietal cortex can cause [...] neglect of the [...] visual hemisphere.
A: spatial; left

Q: Somatosensory Cortex
A lesion in the right posterior parietal cortex can cause [...] syndrome of the [...] hand (can't integrate into higher movements).
A: alien-hand; left

Q: [...] muscle spindles respond most during the [...] phase then go back to baseline. They do not respond during [...].
A: Primary; stretching; release

Q: [...] muscle spindles respond most [...], not [...].
A: Secondary; to the length of muscle; stretching

Q: Pinocchio Ilusion
- Activate muscle spindles in [...] and it feels like your arm is [...], so your nose is growing.
A: bicep; stretching

Q: Hand head illusion
- Activate muscle spindles in [...] and it feels like your arm is [...], so your hand goes through your head.
A: tricep; bending

Q: The order of cells from deep to surface in retina is [...]
A: rods/cones, amacrine cells, bipolar cells, horizontal cells and ganglion

Q: Rods are found in the [...] and are good for [...] due to [...]
A: periphery; faint light; high photopigments and convergence to a single axon

Q: Cones are found in the [...] and are good for [...] due to [...]
A: fovea; bright/colour; minor convergence 6:1 to a ganglion

Visual System
Steps by which light is transduced
1) In the dark, Na channels are open and the cell is depolarized. Therefore glutamate is released and is inhibitory.

Visual System
Steps by which light is transduced
2) In the light, Na channels are closed and the cell is hyperpolarized. Therefore glutamate is not released and is inhibitory.

Q: Retinal ganglion cells produce AP basally when they are [...], it is due to [...] that they change response.
A: fully in the light or in the dark; edges/surround inhibition

Q: [...] in the primary visual cortex perform feature extraction and respond maximally to [...]
A: Simple cells; light/dark bars of a certain orientation
Extra: Recall, Rods/cones have circular receptive fields but if you add them up you get a line.

Visual System
Retinotropic Map
- Information from right hemifield goes to left cortex.
- Ie. Nasal part of right eye crosses over and meets the lateral part of the left eye.

Visual System
Columnar Organization
- Each orientation column responds to light of a certain orientation.
- Each ocular dominance column responds to light from same eye.
- Together form a hypercolumn

Q: Visual System
A lesion in higher areas of the visual cortex can lead to [...]
A: prosopagnosia (can't recognize faces)

Q: Auditory System
- Can detect sounds from [...] Hz
A: 20-20,000

Q: How is air pressure converted to fluid pressure?
1) [...]
2) [...]
3) [...]
A: Outer ear funnels; Malleus, incus and stapes (ossicles) act as lever; Tympanic membrane is larger than oval window

Q: Steps in which sound is [...]
A: transduced
Extra: Variations in air pressure moves the stapes.
Endolymph fluid begins to move in cochlea.
Motion of the basilar membrane and the embedded hair cells.
Increased permeability of hair cells to K+.
Interestingly, the endolymph fluid has a very high concentration of K+.
Depolarization.
Opening of V.G Ca2+ channels.
Release of excitatory neurotransmitter across synaptic cleft.
Action potentials in the auditory nerve.
AP goes to Cochlea nucleus.
Medial and lateral superior olive.
Medial geniculate nucleus (thalamus).
Auditory cortex (temporal lobe)

Final steps in which sound is transduced
Action potentials in the auditory nerve.
AP goes to Cochlea nucleus.
Medial and lateral superior olive.
Medial geniculate nucleus (thalamus).
Auditory cortex (temporal lobe)

Q: [...] frequency sounds are coded for closer to the [...] of the cochlea
A: High; base

Q: [...] frequency sounds are coded for closer to the [...] of the cochlea
A: Low; apex

Q: [...] basilar membrane and [...] hair cells are best for high freq.
A: Narrow/stiff; short/stiff

Q: Loudness is coded for by [...] adapting receptors, thus is both [...]
A: slowly; frequency and population coding

Q: Auditory System
- Sound localization occurs in the [...].
- Two mechanisms include [...]
A: superior olive; interaural differences in intensity and time of sound arrival

Auditory System
Sound localization in superior olive
- Ipsilateral (close) nerve excites and contralateral inhibits.
- Louder ipsi means a higher firing rate

Q: Auditory System
Organization of auditory cortex is both [...]
A: tonotopic and columnar

Q: Auditory System
Lesions in higher areas typically cause issues [...], full deafness requires [...] cortical damage.
A: recognizing sound patterns; bilateral

Auditory System
Cochlear Implant
Microphone-> Transmitter-conduction-> Receiver-> Stimulator

Vestibular System and Eye Movement
3 semicircular canals respond to rotation
- Horizontal: Spin head
- Anterior/saggital: Nodding
- Posterior/frontal: Cartwheeling
2 otolith organs signal linear acceleration
- Saccule signals vertical.
- Utricle signals horizontal.

Q: Vestibular System and Eye Movement
Semicircular canals respond by gelatinous [...] deformed by endolymph in opposite direction to acceleration.
A: cupula

Q: Vestibular System and Eye Movement
Otolinth organs respond by crystal [...] deflecting hair cells constantly based on gravity/acceleration.
A: otolinths

Q: Otolinth organs detect [...]
A: acceleration in any direction and gravity

Vestibular System
-  Deflection towards kinocelium (long-hair) indicates depolarization and higher AP rate.
- AP begin in the 8th cranial nerve.
- Note, this means that semicircular canals work in opposite pairs.

Q: Vestibular System
- Information is used by the visual system and the [...] system to keep us upright, [...] to increase arousal and the [...] to inc. nausea.
A: vestibulospinal; reticular formation; ANS

Q: Vestibular System
The [...] are compensatory eye movements to keep the eyes fixated on an object.
- Movement to the left will cause [...] muscle of right eye and [...] muscle of left eye to contract.
A: vestibular ocular reflex (VOR); lateral; medial/nasal

Q: Vestibular System
If you vibrate someone's achilles tendon to [...] it they will fall [...]
A: "stretch"; backwards

Q: [...] bring our eyes back to centre when they reach their furthest position
A: Saccades

Q: [...]: [...]
- Sign of issue in vestibular system
A: Nystagmus; Involuntary and rapid eye movements disturbing focus

Q: Saccades
- [...] shifts.
- Vision is [...] durring saccade.
- Fixed velocity
- Generated by [...]
A: Fast step-like; inhibited; reticular formation

Q: Smooth Pursuit
- [...] shifts.
- For fast objects, [...]
- Generated by [...]
A: Slow, smooth; breaks down; cerebellum and cerebral cortex

Q: Vestibular Ocular Reflex
- [...]
A: Compensatory movements for head acceleation

Q: Vergence
- [...]
- Non- [...]
A: Eyes turn inwards (eyes move separately!); conjugate

Motor System
Afferent feedback is information from muscles being sent to the Thalamus, Cerebellum and the spinal cord

Motor System
Muscle spindles are found in intrafusal muscle fibers and function to get sensory information, they move in parallel.
- Primary muscle spindles are group 1a and signal velocity and length.
- Secondary muscle spindles are group II and signal length

Q: Motor System
[...] signal pain in muscles
A: Free nerve endings

Q: Motor System
[...] signal tension and function in [...]
A: Golgi Tendon Organs; series

Q: Motor System
Golgi Tendon Organ
- Contraction of muscle [...] organ and opens ion channels.
- Relatively high threshold for [...] stretch, thus respond more to [...] muscle tension.
A: compresses; passive; active

Q: - [...] motor neurons innervate extrafusal muscle fiber.
- Muscle spindles are particularly numerous in [...] muscles (fine control).
[...] motor neuron innervates the intrafusal muscle fibers, supplying efferent control from the muscle system into the intrafusal muscles.
A: Alpha; small; Gamma

Q: Primary muscle spindles increase firing rate when [...], increasing more based on [...].
A: stretched; velocity

Q: Secondary muscle spindles do not increase firing rate when [...], rather only responding to the [...] of the muscle
A: stretched; length

Triune Brain

Limbic System
Main structures include the olfactory bulb (smells), hippocampus memory, amygdala emotions, hypothalamus ANS and cingulate gyrus (basically corpus callosum).

Q: Limbic System
Functions include [...]
A: motivation, emotion, memory and learning

Q: Limbic System
Pain travels via the [...] tract
A: spinothalamic
Extra: sPinoThalamic traCT
Pain, Temp, Crude touch

Q: Limbic System
[...] assigns emotional meaning to pain.
- Eg. Mosquito is annoying.
A: Cingulate gyrus

Q: Limbic System
Hippocampus
- Responsible for [...].
- Shrinks with age (dementia), but inc. with exercise.
A: converting short-term memories into long-term memories

Q: Limbic System
Amygdala
- Responsible for attaching [...]
- When damaged, have reduced fear.
- Bilateral damage means you can't [...]
A: strong emotions to memories; intrepret facial expressions

Q: Hypothalamus
- Main function is for [...], directly through [...] or indirectly through [...]
A: homeostasis; pituitary gland and ANS; behaviour

Q: Limbic System
- Circadian rhythm information comes from the [...]
A: superchiasmatic nucleus

Q: The hypothalamus monitors [...]
A: body temp, osmolarity, glucose and hormone levels

Limbic System
Hypothalamus
Anterior Pituitary
- Hormones are secreted by hypothalamus and come through portal system to the anterior pituitary.
- Either releasing or release-inhibitory hormones.
- Hormones released by anterior pituitary include GH, TSH, LH, FSH, ACTH.

Q: Limbic System
Hypothalamus
Posterior Pituitary
- Hormones are secreted by [...] which are partly in the pituitary and partly in hypothalamus.
- Releases [...] into circulatory system.
A: magnocellular neurons; oxytocin or ADH/vasopressin

Limbic System
Pyrogens such as interleukins or lipopolysaccharides (from bacteria) alter set point to create a fever.
- If set point becomes higher we feel colder

Q: Limbic System
[...] is the satiety center.
- When lesioned will cause [...] since the set point becomes high.
A: ventromedial hypothalamus VMH; obesity

Q: Limbic System
Feedforward mechanism
- [...]
A: Receptors detect cold air before our body temp decreases

Q: Autonomic Nervous System has 3 divisions
[...]
A: Sympathetic (fight/flight), parasympathetic (rest/digest) and enteric (GI)

Q: Autonomic Nervous System mainly functions by controlling [...]
A: smooth muscles and glands

Q: Autonomic Reflex Arc
- Preganglionic nerve is in the [...] and is [...], synapses with [...] nerves which go to target organs.
A: spine; myelinated; non-myelinated

Efferent Pathways of Autonomic Nervous System
Sympathetic
- Leaves middle of spine.
- Ganglion is close to spinal cord
- Short Pre-G and long Post-G
- High ratio of nerves indicates divergence and mass-activation from one pre-G

Efferent Pathways of Autonomic Nervous System
Parasympathetic
- Leaves cervical (top) or saccral (bottom).
- Ganglion is far from spinal cord
- Long Pre-G and short Post-G
- 1:1 ratio

Efferent Pathways of Autonomic Nervous System
Most organs have dual innervation except
1) Blood vessels
2) Sweat glands
3) Piloerector muscles
4) Kidney
5) Spleen
6) Adrenal Gland

Q: Efferent Pathways of Autonomic Nervous System
Adrenal Gland
- Only innervated by [...]
- When stimulated, releases [...]
A: preganglionic SNS; epinephrine

Q: Neurotransmitters of ANS
- All pre-G neurons release [...] onto [...] receptors.
A: Ach; N2

Q: Neurotransmitters of ANS
- PNS post-G neurons release [...] onto [...] receptors.
A: Ach; Muscarinic

Neurotransmitters of ANS
- SNS post-G neurons release norepinephrine onto adenergic receptors.
- Exceptions:
- Post-G neurons in target organs only innervated by SNS release Ach onto Muscarinic receptors.
- Exception plus notice, adrenal gland is basically a collection of post-G, so it releases norepinpehrine.

Cotransmission: Release of other chemicals along with Ach or norepinephrine.
- May include peptides VIP, GnRH, Substance P or nonpeptides ATP, GABA, Dopamine

Q: [...]: [...].
A: Corelease; Release of other chemicals along with Ach or norepinephrine in same vesicle

Q5: B1 is in the heart, B2 in circulatory tissue

Q: Autonomic Nervous System
Autonomic Neuroeffector Junction
- Between ANS and target organs.
- Post-G contains [...] with neurotransmitter.
- Affects [...]
- Release is similar to NMJ
- [...] breaks down neurotransmitters
A: varicosities; many cells; MAO

Autonomic Nervous System
Blood Vessels
- Basal discharge of SNS or PNS is 1 AP/s and is called tonic activity.
- Arteries are only innervated by SNS, so an increase in AP constricts them and a decrease (eg. to 0) in AP dilates them.

Q: Recall, since [...] is not very permeable, [...] doesn't depend on it that much.
A: Na; RMP

Q: When there is light on the off-surround and dark on the center, horizontal cells are [...], but not hyper[...]
A: inactive; polarized

Q: Use/Experience Dependent Plasticity does not change the number of [...]
A: synapses or neurons

Q: Glycine is in the [...]
A: spine

Q: If there is no gamma motorneuron activation, [...] are all off
A: muscle spindles

Major Functions of Vestibular System
1) Sense of equilibrium
2) Postural reflexes, note: decerebate frog has no perception
3) VOR

Q: Receptors do not signal direction, that comes from the [...]
A: somatosensory cortex

Q: The amplitude of a total muscle twitch can be increased by [...] or [...]
A: motor unit recruitment; increased frequency

Q: Plasma has less [...] but more [...] than the interstitial fluid
A: chloride; protein

Q: The nernst equation is only valid if [...] and the cell is [...]
A: there is a gradient; permeable

Q: the longest muscle cell is [...]
A: 12 cm

Q: Z line anchors [...]
A: actin

Q: M line anchors [...]
A: myosin

Q: There are [...] glia than neurons in the brain
A: more