Quiz 1

Question 1

what is a connexon? its composition?

Answer 1

gap junction channel: 6 identical subunits (connexins) > connexon. Many connexons > gap junction

Question 2

How does Ca2+ affect gap junctions?

Answer 2

uncouples electrically coupled neurons by blocking connexons

Question 3

congenital deafness is associated with:

Answer 3

mutations in genes encoding connexins (therefore, gap junctions)

Question 4

Ionotropic receptors are associated with:

Answer 4

generating fast excitation and inhibition in the PNS and CNS

Question 5

Metabrotropic receptors operate through what cellular mechanism?

Answer 5

G-protein coupled receptors > release of 2nd messengeres

Question 6

GABA Type A and Glycine receptors are (inhibitory or stimulatory):

Answer 6

inhibitory

Question 7

acetylcholine is — in skeletal muscle but — in cardiac muscle:

Answer 7

excitatory in skeletal muscle (nicotinic acetylcholine receptor) but inhibitory in cardiac muscle

Question 8

what is the definition of inhibition:

Answer 8

neurotransmitter prevents Vm from reaching Vthreshold

Question 9

what is the definition of excitation:

Answer 9

neurotransmitter promotes depolarization beyond Vthreshold

Question 10

what does having a safety factor of 1:1 mean? where would you find this?

Answer 10

an action potential > an action potential in post-synaptic cell. “yes” or “no” signaling from brain produces immediate response without room for contradicting signals. Found in neuromuscular junction

Question 11

what are muncs?

Answer 11

molecules that prepare SNARES for proper assembly

Question 12

what is the role of synaptotagmin?

Answer 12

PROMOTES neurotransmitter release:
= calcium sensor that releases clamping by complexion; allows structural changes and energy release in order for membrane fusion and exocytsosis of neurotransmitter

Question 13

Botox and tetanus exert their neuronal effects by:

Answer 13

cleaving SNARE proteins to block exocytosis of neurotransmitter

Question 14

the major difference between Botox action and tetanus action:

Answer 14

botox acts at motoneuron junctions; tetanus is transmitted across junction and travels retrogradely to inhibit interneuron neuron

Question 15

What is the cause of Lambert-Eaton Syndrome?

Answer 15

autoimmune disorder in which antibodies “attack” voltage dependent calcium channels needed for triggering fusion in presynaptic motor neurons and cholinergic neurons

Question 16

What are they symptoms of Lambert-Eaton Syndrome?

Answer 16

decreased efficacy of Ca2+ channels decreases ACh release and compromises synaptic transmission&raquo_space; muscle weakness, fatigue and autonomic dysfunction

Question 17

What is the basis of myasthenia gravis?

Answer 17

antibodies directed at ACh receptors or MuSK enzyme that clusters AchRs.

Question 18

how does desensitization occur?

Answer 18

prolonged exposure to acetylcholine causes a conformational change of ligand-gated ion channels to a non-conducting state.

Question 19

what is the significance of m = N x P

Answer 19

m is Mean quantal content and it represents the average amount of neurotransmitter at a synapse. n is number of vesicles and p is probability of being released. M is high in NMJ so that a single action potential can > reaction. M is low in the CNS to allow for controlled response to input. M can change in CNS = synaptic plasticity

Question 20

What is the key difference between constitutive fusion/secretion and the rapid exocystosis exhibited by synapses?

Answer 20

coupling of Ca2+ to synaptic vesicle fusion allows for rapid kinetics

Question 21

If Vreversal is more negative than Vthreshold for an action potential, then that particular receptor’s activation will produce what kind of signal?

Answer 21

inhibitory

Question 22

what is the importance of allosteric modulation in neurons?

Answer 22

modulation of neurotransmitter receptors can alter that receptor’s effect when nt binds. ex: psychoactive drugs that allosterically modify GABAa receptors.

Question 23

the pre central gyrus contains neurons for:

Answer 23

controlling movement of face and extremities

Question 24

the postcentral gyrus contains neurons for:

Answer 24

sensation

Question 25

the premotor cortex of the frontal lobe is located anterior to —— and is responsible for;

Answer 25

anterior to precentral gyrus; planning and initiating movement

Question 26

the dorsolateral prefrontal cortex is responsible for:

Answer 26

executive functions such as working memory, planning, problem solving, reasoning and organizing

Question 27

orbitomedial prefrontal cortex of the frontal lobe is responsible for:

Answer 27

impulse control, personality, reactivity to the surroundings and mood

Question 28

What is Broca’s area?

Answer 28

responsible for motor language. located in the inferior frontal gyrus

Question 29

attention and visuospatial function are controlled by which lobe?

Answer 29

posterior part of the parietal lobe

Question 30

the parahippocampus and hippocampus are responsible for:

Answer 30

short term memory

Question 31

the uncus is:

Answer 31

a swelling over the amygdala

Question 32

macroglia are derived from:

Answer 32

neuroectoderm (from neural tube)

Question 33

types of macroglia include:

Answer 33

astrocytes, oligodendrocytes, ependymal cells, choroid plexus epithelial cells and radial glia

Question 34

microglia are derived from:

Answer 34

mesoderm. Part of macrophage monocyte family

Question 35

Schwann cells are derived from —- and form myelin of the —-

Answer 35

neural crest cells; PNS

Question 36

what is the role of astrocytes:

Answer 36

structural support, scaffolding, potassium regulation, blood brain barrier and tripartite synapse (important for removing neurotransmitter, neuron survival); metal detoxification; release of trophic factors; recycle of cytotoxic glutamate

Question 37

why are glial tumors difficult to remove?

Answer 37

made up of astrocytes (glial cells) which

Question 38

oligodendrocytes:

Answer 38

form myelin sheath of CNS

Question 39

the basal plate contains what type of neurons? the alar plate?

Answer 39

basal – motor

alar – sensory