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MCAT-PSYCHOLOGY > Biological Foundations of Behaviour > Flashcards

Biological Foundations of Behaviour Flashcards

1
Q

action potential

A

an electrochemical impulse that consists of localized areas of depolarization of the plasma membrane that travels in a wave-like manner along an axon

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2
Q

synaptic transmission

A

when an action potential reaches the end of an axon at a synapse, the signal is transformed into a chemical signal with the release of neurotransmitter into the synaptic cleft

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3
Q

bipolar

A

neurons with one dendrite

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4
Q

multipolar

A

multipolar

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5
Q

how many axons do all neurons have?

A

only one

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6
Q

synaptic knobs

A

the terminal end of the axons that form connections with target cells

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7
Q

synaptic cleft

A

the small gap between the synaptic knob and the target cell

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8
Q

what is a neuron’s resting membrane potential?

A

-70mV

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9
Q

what are the two primary membrane proteins that determine the resting membrane potential?

A

sodium potassium pump and potassium leak channels

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10
Q

how does the sodium potassium pump work?

A

for every ATP, three sodium ions are pumped out of the cell and two potassium ions pumped into the cell

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11
Q

in which direction does potassium flow through potassium leak channels?

A

out of the cell

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12
Q

polarized

A

difference in charge across membrane of neuron, negative on the inside and positive on the outside

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13
Q

depolarization

A

change in membrane potential from resting -70mV to +35mV

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14
Q

repolarization

A

returns the membrane potential to normal

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15
Q

what causes the change in membrane potential during the passage of an action potential?

A

movement of ions in and out of neurons through ion channels

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16
Q

voltage-gated sodium channels

A

opens at -50mV and close at +35mV, allows sodium ions to flow into cell

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17
Q

threshold potential

A

-50mV, must reach this potential for voltage-gated sodium channels to open

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18
Q

what allows for repolarization

A

1) voltage-gated sodium channels inactivate at +35mV
2) voltage-gated potassium channels open at +35mV and stay open until -90mV
3) potassium leak channels contribute to repolarization

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19
Q

myelin

A

an insulating sheath wrapped around some neurons, no ions can exit or enter axonal membranes covered in myelin

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20
Q

what cells create the myelin sheath?

A

Schwann cells

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21
Q

nodes of Ranvier

A

gaps in the myelin sheath where voltage-gated sodium and potassium channels and concentrated

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22
Q

saltatory conduction

A

the rapid jumping conduction in myelinated axons at Nodes of Ranvier

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23
Q

glial cells

A

specialized non-neuronal cells that typically provide structural and metabolic support to neurons, do not generate action potentials

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24
Q

what are the five types of glial cells?

A

Schwann cells, oligodendrocytes, astrocytes, microglia, ependymal cells

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25
Q

Schwann cells

A

PNS glial cell, forms myelin to increase speed of conduction of action potentials along axon

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26
Q

oligodendrocytes

A

CNS glial cell, forms myelin to increase speed of conduction of action potentials along axon

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27
Q

astrocytes

A

CNS glial cell, guides neuronal development, regulates synaptic communication via regulation of neurotransmitter levels

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28
Q

microglia

A

CNS glial cell, remove dead cells and debris

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29
Q

ependymal cells

A

CNS glial cell, produce and circulate cerebrospinal fluid

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30
Q

equilibrium potential

A

the membrane potential at which the gradient does not exist and there is no net movement of ions across the membrane, specific to each particular ion

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31
Q

what is the equilibrium potential for Na+?

A

+50mV

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32
Q

what is the equilibrium potential for K+?

A

-90mV

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33
Q

refractory

A

the state of a neuron after passage of an action potential in which it is unresponsive to membrane depolarization and unable to transmit another action potential

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34
Q

absolute refractory period

A

a neuron will not fire action action potential no matter how strong a membrane depolarization is induced: VOLTAGE-GATED SODIUM CHANNELS HAVE BEEN INACTIVATED (+35mV to -70mV)

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35
Q

relative refractory period

A

neuron can be induced to transmit an action potential but the depolarization required is greater than normal because the membrane is hyperpolarized: VOLTAGE-GATED POTASSIUM CHANNELS HAVE NOT CLOSED YET (-70mV to -90mV)

36
Q

synapse

A

junction between the axon terminum of a neuron and the dendrites, soma, or axon of a second neuron or an organ

37
Q

electrical synapse

A

when the cytoplasms of two cells are joined by gap junctions, allows an action potential to spread directly from one cell to another (ex. smooth and cardiac muscle)

38
Q

chemical synapse

A

found at the ends of axons where they meet their target cell, action potential is converted into a chemical signal

39
Q

what is the neurotransmitter released at a neuromuscular junction?

A

acetylcholine (ACh)

40
Q

excitatory neurotransmitter

A

opens a channel that depolarizes the postsynaptic membrane

41
Q

inhibitory neurotransmitter

A

makes the membrane potential more negative than the resting potential (hyperpolarized)

42
Q

what determines the effect of the neurotransmitter on the postsynaptic cell?

A

the receptor for the neurotransmitter and its associated ion channel

43
Q

what kind of event is an action potential?

A

all or nothing: speed and magnitude of depolarization do not vary from one action potential to another

44
Q

summation

A

the addition of stimuli

45
Q

excitatory postsynaptic potentials (EPSP’s)

A

excitatory neurotransmitters that cause postsynaptic depolarization

46
Q

inhibitory postsynaptic potentials (IPSPs)

A

inhibitory neurotransmitters that cause postsynaptic hyperpolarization

47
Q

temporal summation

A

a single presynaptic neuron fires action potentials so rapidly that EPSPs or IPSPs pile up on top of each other

48
Q

spatial summation

A

EPSPs and IPSPs from all the synapses on the postsynaptic membrane are summed at a given moment in time

49
Q

what is the sensory function of the nervous system

A

receiving information (PNS)

50
Q

what is the integrative function of the nervous system

A

processing the information (CNS)

51
Q

what is the motor function of the nervous system

A

acting on the integrative processes (PNS)

52
Q

motor neurons

A

carry information from the nervous system toward organs which can act upon that information

53
Q

effectors

A

organs that act upon the information carried by motor neurons

54
Q

efferent neurons

A

motor neurons that carry information away from the CNS and innervate effectors

55
Q

afferent neurons

A

sensory neurons which carry information toward the central nervous system

56
Q

reflex

A

the simplest form of nervous system activity, in which a direct motor response to sensory input occurs without conscious thought

57
Q

monosynaptic reflex arc

A

a reflex that involves only two neurons and one synapse (spinal cord) ex. muscle stretch reflex

58
Q

inhibitory interneuron

A

a short neuron which forms an inhibitory synapse with a motor neuron, example of the integrative role of the nervous system, ex. reciprocal inhibition of muscles

59
Q

nuclei

A

bunches of neuronal cell bodies in the CNS

60
Q

ganglia

A

bunches of neuronal cell bodies located outside of the CNS

61
Q

what does the CNS consist of?

A

spinal cord and brain

62
Q

another word for hindbrain

A

rhombencephalon

63
Q

another word for midbrain

A

mesencephalon

64
Q

another word for forebrain

A

prosencephalon

65
Q

how many cranial and spinal nerves are there?

A

12 pairs of cranial and 31 pairs of spinal nerves

66
Q

vagus nerve

A

a cranial nerve that decreases heart rate and increases GI tract activity, part of the parasympathetic division of the autonomic nervous system

67
Q

what is the organization of the somatic PNS?

A

all somatic motor neurons innervate skeletal muscle cells, use ACh as their neurotransmitter, have their cell bodies in the brainstem or the ventral portion of the spinal cord, have a long dendrite extending from a sensory receptor toward the soma (located just outside the CNS in a dorsal root ganglion)

68
Q

dorsal root ganglion

A

bunch of somatic (and autonomic) sensory neuron cell bodies located dorsal to the spinal cord. outside the meninges but within the vertebral column, considered outside of the CNS

69
Q

meninges

A

protective sheath of the brain and cord

70
Q

where is the first synapse of somatic sensory neurons?

A

in the CNS

71
Q

preganglionic neuron

A

cell body in the brainstem or spinal cord, sends an axon to an autonomic ganglion located outside the spinal column

72
Q

postganglionic neuron

A

synapses with preganglionic neuron, sends an axon to an effector (smooth muscle or gland)

73
Q

what does the organization of autonomic PNS consist of?

A

preganglionic and postganglionic neurons

74
Q

what is the neurotransmitter released by autonomic preganglionic neurons?

A

acetylcholine

75
Q

what is the neurotransmitter released by autonomic parasympathetic postganglionic neurons?

A

acetylcholine

76
Q

what is the neurotransmitter released by autonomic sympathetic postganglionic neurons?

A

norepinephrine (NE)

77
Q

where is the cell bodies of sympathetic preganglionic efferent neurons located?

A

thoracic (chest) or lumbar (lower back) regions of spinal cord

78
Q

where is the cell bodies of parasympathetic preganglionic efferent neurons located?

A

craniosacral (in the head/cranium or lower back/sacral portion)

79
Q

length of the preganglionic axon in the sympathetic system:

A

short, few but large ganglia, very long post-ganglionic cell

80
Q

length of the preganglionic axon in the parasympathetic system

A

long, small ganglion close to effector, short post-ganglionic cell

81
Q

how are autonomic afferent (sensory) neurons different to somatic afferent neurons?

A

they can synapse in the PNS (at the autonomic ganglia) with autonomic efferent neurons to form a “short reflex”

82
Q

adrenal gland

A

located above each kidney, consists of the inner medulla and outer cortex

83
Q

what hormones does the adrenal cortex secrete?

A

glucocorticoids, mineralocorticoids, and some sex hormones

84
Q

what system is the adrenal medulla part of?

A

the sympathetic nervous system, it is directly innervated by sympathetic preganglionic neurons

85
Q

what does the adrenal gland release when the sympathetic system is activated?

A

epinephrine (adrenaline), acts like a neurotransmitter because of rapid but short effects

MCAT-PSYCHOLOGY (11 decks)

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