Neurophysiology

Front 1

List the 5 subdivisions of the brain, and the corresponding structures.

Back 1

Telencephalon--cerebrum (cortex, amygdalia, basal ganglia)

Diencephalon--Thalamus, Hypothalamus

Mecencephalon--midbrain

Metencephalon--pons, cerebellum

Myelencephalon--Medulla

Front 2

Where are the cells of origin for sympathetic and parasympathetic pathways?

Back 2

sympathetic--intermediolateral cell column (T1-L3)

parasympathetic--cranial nerve nuclei (midbrain & medulla), sacral spinal cord (S2-S4)

Front 3

List 4 types of glial cells and their functions.

Back 3

Oligodendrocytes--manufacture myelin in CNS

Schwann cells--manufacture myelin in PNS

Astrocytes--NT uptake, absorption of excess K+

Microglia--phagocytose dead neural tissue

Front 4

Describe Wallerian degeneration.

Back 4

Axon distal to lesion (to terminal) degenerates: anterograde

Front 5

Define chromatolysis.

Back 5

Happens to the cell body when axon proximal to lesion degenerates (retrograde degeneration)

Front 6

Define transsynaptic degeneration.

Back 6

damage to a cell that receives the damaged projection (anterograde transsynaptic degeneration) or a cell that projected to the damaged neuron (retrograde transsynaptic degeneration).

Front 7

Define sprouting in the context of nerve regeneration.

Back 7

regenerating nerve grows along the Schwann cell path at a rate of ~1mm day.

Front 8

List the Nernst equation.

Back 8

Vx=(RT/zF)ln[X]o/[X]i

Front 9

Define equilibrium potential.

Back 9

The equilibrium potential of an ion is the potential to which the ion will bring the membrane, if it is free to diffuse.

Front 10

List the Goldman equation.

Back 10

Vm=(RT/F)ln(pK[K]o/pK[K]i)+(pNa[Na]o/pNa[Na]i)+(pCl[Cl]o/pCl[Cl]i)

Front 11

Define Nernst potential

Back 11

equation that describes the movement of an ion from high concentration to low concentration in terms of temperature, valence, and concentration

Front 12

Define reversal potential.

Back 12

the potential in a voltage clamp experiment at which the current reverses direction; indicates that ion's resting membrane voltage

Front 13

the point at which the Na current is equal to the K current.

Back 13

threshold

Front 14

causes the rapid depolarization of the upstroke of the AP

Back 14

Na cycle

Front 15

action of tetrodotoxin

Back 15

blocks Na channels

Front 16

the inverse of resistance:

Back 16

conductance

Front 17

antibody reaction to ACh channels in skeletal muscle.

Back 17

Myasthenia gravis

Front 18

antibody reaction to presynaptic Ca channels.

Back 18

Eaton-Lambert myasthenic syndrome

Front 19

demyelination of PNS axons which can recover (Schwann cells). Initially following loss of myelin, there are conduction failures due to lack of Na+ channels in internodal membrane. Eventually, some Na+ channels develop and conduction (albeit slowed) can occur.

Back 19

Guillain-Barré syndrome

Front 20

a genetic disease in which a triple dose (3 genes) of peripheral myelin exists, leading to decreased conduction, demyelination and muscle
weakness.

Back 20

Charcot-Marie-Tooth Disease

Front 21

Receptor potentials that generate APs directly(somatosensory receptors, olfactory receptors).

Back 21

generator potentials

Front 22

receptors that can signal intensity and duration of the stimulus.

Back 22

slowly adapting receptor

Front 23

the rate of change (dynamic property) of the stimulus is signaled (onset and offset).

Back 23

rapidly adapting receptor

Front 24

respond to position and movement of
limbs (kinesthesia).

Back 24

Joint Receptor endings

Front 25

signals tension of muscle during contraction

Back 25

Golgi tendon organ

Front 26

sensory receptor and axon that communicates sense information to the CNS. Cell body usually located in the dorsal root ganglion or cranial nerve ganglion.

Back 26

First-order neuron

Front 27

from spinal cord or brainstem projects to the part of the thalamus that is specific for that sense modality.

Back 27

Second-order neuron

Front 28

from the thalamus, projects to the 1° sensory cortex specific for
that modality.

Back 28

Third-order neuron

Front 29

enbles the body to respond quickly to unexpected changes in load (maintenance of upright posture).

Back 29

stretch reflex

Front 30

nerve lesion resulting in clonus

Back 30

upper motor neuron

Front 31

neurons in the spinal cord that receive excitatory input from
á-MNs and inhibit á-MNs.

Back 31

renshaw cells

Front 32

contraction of distal portion of spindle fibers, which stretches the
spindle, causing increased Ia, II discharge.

Back 32

gamma motor neurons

Front 33

ascend in fasciculus gracilis and synapse in nucleus gracilis

Back 33

afferents from lower extremities (T7 and lower)

Front 34

in fasciculus cuneatus and synapse in nucleus cuneatus

Back 34

afferents from upper extremities (T6 and higher)

Front 35

where is the soma of a neuron who’s axon is in the dorsal column?

Back 35

dorsal root ganglion

Front 36

hemisection: all sensory loss below level of lesion, loss of tactile sensation ipsilateral to lesion, loss of pain and temperature contralateral to the lesion (in predicting sensory and motor loss following a lesion, (remember to start at the lesion and follow tracts distally).

Back 36

Brown-Séquard Syndrome

Front 37

cyst that forms from within the center of the spinal cord (intra-axially), leading to a bilateral loss of pain/temp sensation in the affected body segments.

Back 37

Syringomyelia

Front 38

size of a motor unit is determined by:

Back 38

the number of fibers that the á-MN innervates

Front 39

Increasing the strength of contraction is accomplished by:

Back 39

recruiting more motor units

Front 40

recruitment order of motor neurons:

Back 40

slow twitch, fast twitch fatigue-resistant, fast twitch fatigable (small->medium->large)

Front 41

motor neuron damage that will decrease or eliminate the stretch reflex, due to damage to the á-MN, Ia afferents, or the muscle itself.

Back 41

LMN

Front 42

motor neuron lesion that will cause exaggerated stretch reflexes due to release of the á-MN from descending inhibitory influences.

Back 42

UMN

Front 43

1° motor cortex area located at the pre-central gyrus (frontal lobe)

Back 43

area 4

Front 44

rostral to area 4, located in the premotor cortex

Back 44

area 6

Front 45

frontal eye field area located rostral to area 6 (frontal lobe)

Back 45

area 8

Front 46

Broca’s area (speech production)located in the ventral part of frontal lobe

Back 46

area 44/45

Front 47

1° somatosensory cortex located in the post-central gyrus (parietal lobe)

Back 47

area 3,1,2

Front 48

1°, 2° auditory cortex located in the superior temporal gyrus

Back 48

areas 41,42

Front 49

1° visual cortex located in the calcarine sulcus and occipital pole

Back 49

area 17

Front 50

visual association cortex surrounding area 17 (occipital)

Back 50

areas 18, 19

Front 51

Wernicke’s area (speech recog.)located in the inferior parietal lobe

Back 51

areas 39,40

Front 52

define optical power.

Back 52

reciprocal of the focal length in meters (58.8 diopters for an ideal 17 mm eye)

Front 53

components of the eye with refractive power

Back 53

lens and cornea

Front 54

enables accomodation of the eye for close objects

Back 54

contraction of the ciliary muscle releasing tension on the suspensory ligaments (zonule of zinn) and allowing thelens to fatten

Front 55

nucleus located in the midbrain below the superior colliculus

Back 55

Edinger Westphal nucleus

Front 56

correction for nearsightedness (myopia; eye too long)

Back 56

concave lens

Front 57

order of processing in the retina

Back 57

photoreceptors (rods and cones) > bipolar cells > retinal ganglion cells.

Front 58

first neurons in the processing stream of vision to produce action potentials

Back 58

ganglion cells

Front 59

describes a state of open Na+ channels in photoreceptors, allowing a steady depolarizing Na+ influx

Back 59

dark current

Front 60

causes release of excitatory transmitter onto bipolar cells, inducing a constant depolarization. Outward current at the soma is carried by K+, and ionic balances are maintained by the Na+/K+ pump.

Back 60

dark current

Front 61

hyperpolarizes the photoreceptor

Back 61

light

Front 62

steps in light hyperpolarization of photoreceptors

Back 62

1. activation of rhodopsin
2. rhodopsin activates transducin
3. transducin activates PDE
4. PDE lowers cGMP
5. cGMP dissociates from Na+ channel
6. Na+ channel closes

Front 63

amplification of photoreceptor hyerpolarization

Back 63

1 rhodopsin activates 250,000 phosphodiesterases

Front 64

more sensitive photoreceptors used in low-light conditions (scotopic vision)

Back 64

rods

Front 65

photoreceptor requiring more light that is sensitive to different wavelengths (photopic)

Back 65

Cones

Front 66

ratio of cones:rods in the fovea

Back 66

100% cones

Front 67

visual system cells containing AMPA receptors that depolarize in response to glutamate

Back 67

off-center bipolar cells

Front 68

visual system cells containing metabotropic receptors (coupled to G-proteins) that hyperpolarize in response to glutamate

Back 68

on-center/off-surround bipolar cells

Front 69

important visual pathway for object discrimination

Back 69

Parvocellular pathway to
temporal cortex

Front 70

Rule of L for vision organization:

Back 70

Lower half of retina
Lateral half of LGB
Loop of Meyer
Lingual gyrus

Front 71

lesion producing right monocular blindness

Back 71

right optic nerve (or getting stabbed in the right eye)

Front 72

lesion resulting in homonomous hemianopsia

Back 72

lateral geniculate, optic tract, optic radiations, visual cortex

(LOOV)

Front 73

lesion giving lower field homonymous quadrantanopsia:

Back 73

cuneus

Front 74

lesion giving upper field homonymous
quadrantanopsia:

Back 74

loop of Meyer or lingual gyrus

Front 75

lesion producint homonymous hemianopsia with macular sparing:

Back 75

lesion to calcarine artery

Front 76

lesion producing bitemporal homonymous hemianopsia:

Back 76

pituitary tumors which encroach on the optic chiasm

Front 77

increased cranial pressure is transmitted via the subarachnoid space to the papilla (blind spot) where the optic nerve exits the retina. Swelling of the axons can be seen as blurring of
the disk margin.

Back 77

papilledema