Neurophysiology (Test 1)

Question 1

What cells are responsible for myelination?

Answer 1

oligodendrocytes and Schwann cells.

Question 2

Which channels mediate transmitter release at the presynaptic terminal?

Answer 2

Ca2+ channels.

Question 3

What is the ion and direction of flow in the action potential phase 3:

Answer 3

Na+ ions flow into cell.

Question 4

What is the order of the types of synapse in escape response in terms of fast?

Answer 4

Gap junction, ligand-gated, G-protein-coupled.

Question 5

What is the main fast inhibitory transmitter in the nervous system?

Answer 5

GABA.

Question 6

What is the structure circled in the picture? From where is it derived?

Answer 6

Thalamus, diencephalon

Question 7

What are the neurotransmiters of the preganglionic neuron and the postganglionic neuron of sympathetic nervous system?

Answer 7

Acetylcholine, norepinephrine.

Question 8

What nervous system’s function is refer to as ‘Fight or flight’?

Answer 8

Sympathetic nervous system.

Question 9

What are the functions of the cerebellum?

Answer 9

Movement, posture, balance.

Question 10

Is the autonomic nervous system voluntary or involuntary?

Answer 10

involuntary

Question 11

How any types of synapse does the autonomic nervous system consist of?

Answer 11

Two, Cholinergic and adrenergic.

Question 12

Sensory afferents that cross immediately when entering the spinal cord carries___________ information and ascends in which pathway?

Answer 12

Pain and temperature; spinothalamic tract.

Question 13

What is the only sensory information that doesn’t first synapse in the thalamus before reaching the cortex?

Answer 13

Olfactory.

Question 14

Where is the tonotopic organization of the auditory system originates from?

Answer 14

Basilar membrane.

Question 15

What is the depolarization of taste cells in response to a salty taste mediated?

Answer 15

Na+ ions flowing through an amilioride-sensitive Na+ channel.

Question 16

What types of the sensory receptor cells of the visual system are?

Answer 16

Rods and cones.

Question 17

What is the equilibrium potential of an ion dependent on?

Answer 17

Valence of the ion, temperature and intra- and extracellular concentration of the ion.

Question 18

What is the main excitatory neurotransmitter in the brain?

Answer 18

glutamate

Question 19

In general, by which root the sensory afferents enter and motor efferents exit the spinal cord?

Answer 19

Sensory afferents enter the spinal cord dorsally and motor efferents exit the spinal cord ventrally.

Question 20

What makes cerebrospinal fluid?

Answer 20

Choroid plexus

Question 21

What are the functions of cranial nerve X (Vagus Nerve)?

Answer 21

The vagus nerve is responsible for such varied tasks as heart rate, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech (via the recurrent laryngeal nerve) and keeping the larynx open for breathing.

Question 22

What is the area of the body or visual space that when stimulated leads to activity in a primary sensory neuron called?

Answer 22

Receptive field.

Question 23

After crossing in the medulla, ascending sensory information travels in what structure to reach the thalamus?

Answer 23

Medial lemniscus.

Question 24

What ion in the endolymph surrounding cilia of the hair cells generates the endocochlear potential?

Answer 24

High K+ concentration.

Question 25

What kind of shape change of the lens in near-sighted vision.

Answer 25

Rounded.

Question 26

What is the intensity of a sensory stimulus encoded by?

Answer 26

The frequency of action potentials fired.

Question 27

What is the “dark current” (depolarizing current) in photo sensory cells mediated by?

Answer 27

A continual influx of Na+ ions.

Question 28

What is the neurotransmitter of postganglionic neurons in the parasympathetic nervous system?

Answer 28

Acetylcholine.

Question 29

Most sensory information synapses in what structure where neurons then send axons on to the cortex?

Answer 29

Thalamus.

Question 30

What causes congenital birth defects such as anencephaly and spina bifida?

Answer 30

Failure of the neural tube to close.

Question 31

What current is responsible for repolarizing the cell during action potential?

Answer 31

A slow-onset and continuous outward K+ current.

Question 32

If the capacitance of a membrane is increased, it will have what affect on the time course (i.e., time constant τ) of membrane response to current pulses?

Answer 32

increase

Question 33

What factors will influence the threshold for ‘two-point discrimination’ sensory tasks?

Answer 33

Receptor density, size of receptive field and lateral inhibition.

Question 34

What is the cellular response to light falling on a photoreceptor?

Answer 34

Hyperpolarize and refrain from releasing transmitter in amounts corresponding to the light intensity

Question 35

What is the function of cholinesterase inhibitors?

Answer 35

The inhibition of break-down of acetylcholine in the synaptic cleft.

Question 36

Reuptake of autonomic monoamine neurotransmitter is an important physiological regulation on synapse function. List three mechanisms that mediate the reuptake of these neurotransmitters.

Answer 36

(1) serotonin transporter (SERT), blocked by selective serotonin reuptake inhibitors (SSRI) (2) norepinephrine transporter (NET), blocked by tricyclic antidepressant (TCA) (3) dopamine transporter (DAT), blocked by amphetamines cocaine blocks all three.

Question 37

What is the function Wernicke’s area and Broca’s area of the cerebral cortex?

Answer 37

Wernicke’s area is involved in the understanding of written and spoken language. Broca’s area is involved the production of language.