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Flashcards in Nervous System Deck (110):
1

non-excitable cells that provide structural support or that serve important functions in the nervous system

support cells

2

glial cells

aka support cells

3

atom with a positive or negative charge

ion

4

brain and spinal cord

central nervous system

5

nervous system that lies outside the brain and spinal cord

peripheral nervous system

6

excitable and can communicate with muscle and glands, receive and integrate signals at 1 location and transmit action potential at another, basic functional unit of the nervous system

neurons

7

cell that receives signal from a neuron or hormone, can be another neuron, muscle or gland

target cell

8

cell body, receptive portion, transmitting portion

3 neuron characteristics

9

located centrally, main nutritional and metabolic region, receives signal and sends toward axon

cell body/soma/perikaryon

10

extend from soma, branching processes, receive signal (afferent), may serve as sensory receptors

dendrites

11

thin and extend from soma, generates action potential/nerve impulse and conducts (efferent) it to the next cell, varies in length

axons

12

long distance regenerative electrical signal transmitted along an axon

action potential

13

junctions between a neuron and its target cell

synapses

14

each neuron has a signal which arises from the cell body, 1st portion of the axon

axon hillock

15

a branch of an axon

axon terminal

16

insulation surrounding axons, formed by support cells that wrap repeatedly around an axon forming a thick layer of cell membrane

myelin sheath

17

1 type of support cell in the nervous system, found in PNS, form myelin sheath around axons

schwann cells

18

tiny areas of bare axons between neighboring segments of myelin sheath, in a myelinated axon, charge forms across the membrane only at the nodes so the action potential appears to jump along the axon

nodes of ranvier

19

selective, passive or active, regionally located, control movement of ions across the neuronal membrane, these tiny structures make neurons excitable

ion channels

20

proteins that are embedded in the lipid bilayer of the cell membrane

integral proteins

21

depends on charge of ion, how much water the ion attracts and holds around it

channel selectivity

22

ion channels that can be opened or closed by gates

active channels

23

always open, resting membrane potential, located in the cell membrane, cell body, and axon

passive channels

24

gates are opened or closed by changes in the membrane voltage, located on axon hillock, myelinated and unmyelinated sheaths, and nodes of ranvier, action potential

voltage gated channels

25

the electrical potential or voltage across a cell membrane that results from the separation of charged particles across the membrane

membrane potential

26

a chemical released at a synapse, GABA or ACH

neurotransmiter

27

gates that open or close when a neurotransmitter binds to them, located in dendrites, and cell body, responsible for synaptic response

chemically gated channels

28

a short distance electrical signal that can vary in amplitude

synaptic potential

29

sensory functions, integrating functions, motor functions

3 main activities

30

conduct impulses toward CNS, also called sensory nerves, located in the dorsal horns

afferent nerve fibers

31

conduct impulses away from CNS, also called motor nerves, located in ventral horns

efferent nerve fibers

32

nerves may contain both kinds of nerve fibers

PNS mixed nerves

33

coordination of automatic body functions (ie stimulation of digestive juices in response to ingestion of a meal)

autonomic nervous system

34

conscious or voluntary control of skeletal muscles

somatic nervous system

35

specialized molecule to help maintain cell resting state
Na pumped out
K pumped in

Na K pump

36

difference in electrical charge across a neuron's membrane, a net negative charge

resting membrane potential

37

neuron is not being stimulated, Na has been pumped out of cell, K has been pumped in, net negative charge inside the cell

resting state

38

neuron receives external stimulus, Na channel opens on neuron cell membrane, Na neurons flow into cell by passive diffusion, charge now positive inside cell

depolarization

39

switching of electrical charge from negative to a positive

action potential

40

Na channels are closing, K channels are opening, K ions flow out of cell, net charge is returning to negative

beginning of repolarization

41

sufficient outflow of K ions restored to net negative charge inside the cell
Na and K ions are on opposite sides of cell membrane from where they started
ion distribution is reversed

repolarization

42

electric charges flip across cell membrane (depolarization) following by unflipping of the electric charges (repolarization)
an area is depolarized, an adjacent area is stimulated, spreading a wave of depolarization

nerve impulse

43

stimulus is strong enough to cause complete depolarization and to generate a nerve impulse

threshold stimulus

44

very brief time period when a neuron is insensitive to additional stimuli

refractory period

45

during Na influx and early K outflow

absolute refractory period

46

during end of repolarization period, possible to stimulate another depolarization if stimulus is very large

relative refractory period

47

gap between 2 adjacent neurons or between a neuron and a target cell

synaptic cleft

48

brings depolarization to the synapse and releases neurotransmitter

presynaptic neuron

49

contains receptors for the neurotransmitter released by the presynaptic neuron

postsynaptic neuron

50

perpetuation of the nerve impulse from one neuron to the next cell
depolarization wave triggers Ca influx into synaptic knob membrane
Ca causes vesicles to dump neurotransmitter into synaptic cleft

synaptic transmission

51

usually cause influx of Na so postsynaptic membrane moves toward threshold, beginning a new impulse

excitatory neurotransmitters

52

make inside of cell more negative, moving the charge within the postsynaptic cell father away from the threshold

inhibitory neurotransmitters

53

excitatory at somatic motor neurons, inhibitory is PSNS stimulation of the heart, primary neurotransmitter for parasympathetic nervous system

acetycholine

54

norepinephrine, epinephrine, dopamine neurotransmitters

catecholamines

55

brain, inhibitory neurotransmitter

GABA

56

spinal cord, inhibitory neurotransmitter

glycine

57

somatic nervous system fight or flight
primary neurotransmitter for sympathetic nervous system

norepinephrine

58

adrenal release, somatic nervous system fight or flight

epinephrine

59

autonomic fine muscle function

dopamine

60

the action stimulated depends on the type of neurotransmitter released (excitatory or inhibitory)

CNS post synaptic receptors

61

contains most of the neuron cell bodies

gray matter

62

contains most of the myelinated nerve fibers

white matter

63

functions associated with learning and intelligence
receives and interprets sensory information
regulates conscious behavior

cerebrum

64

responsible for coordinated movement, balance, posture and complex reflexes

cerebellum

65

role in temperature regulation, hunger, thirst and rage/anger responses

diencephalon

66

autonomic, cranial nerves originate here, responsible for maintenance of basic support functions of the body

brain stem

67

connective tissue layers that surround the brain and spinal cord, supply nutrients and oxygen and provide cushioning

meninges (DAP)

68

fluid between layers of meninges and in canals and cavities inside brain and spinal cord

cerebrospinal fluid

69

separates capillaries in the brain from nervous tissue

blood brain barrier

70

12 pairs of nerves in PNS that originate directly from the brain, each may contain motor, sensory and mixed neurons

cranial nerves

71

conducts sensory information and motor instructions between brain and rest of the body

spinal cord

72

sensory or afferent nerve fibers

dorsal nerve roots

73

motor or efferent nerve fibers

ventral nerve roots

74

cluster of neuroal bodies outside the CNS

ganglio

75

neurons in the cell body in the brain or spinal cord

preganglionic neuron

76

neurons connected to a target organ

postganglionic neuron

77

part of the autonomic nervous system, fight or flight response, helps the body cope in emergency situations

sympathetic nervous system

78

part of the autonomic nervous system, rest and restore, brings the body back to resting state, facilitates all body processes to replace resources used during the emergency

parasympathetic nervous system

79

neurons that release norepinephrine

adrenergic neurons

80

alpha, beta 1 and beta 2, all stimulated norepinephrine

3 types of receptors affected by sympathetic nervous system

81

vasoconstriction of skin, GI tract, kidney

alpha

82

increases heart rate and force of contraction

beta 1

83

bronchodilation

beta 2

84

nicotinic and muscarinic receptors

2 types acetylcholine receptors

85

found on postganglionic neurons of both sympathetic and parasympathetic systems

nicotinic receptors

86

on tissues supplied by postganglionic neuron of parasympathetic nervous system

muscarinic receptors

87

rapid, automatic response to stimuli, designed to protect the body and maintain homeostasis

reflexes

88

somatic, autonomic, contralateral (opposite sides), ipsilateral (same sides)

4 types of reflexes

89

reflex arc

1. sensory receptor detects a change
2. then sends action potential along sensory neuron to gray matter of spinal cord or brain stem
3. sensory neuron synapses with other neurons
4. integrated response is sent out by motor neuron to target organ

90

types of reflexes

stretch
withdrawal
crossed extender
palpebral
pupillary light respons

91

involves a sensory neuron and a motor neuron, only 1 synapse and no interneurons

stretch reflex

92

several interneuron synapses in different segments on the same side of the spinal cord, results in contraction or flexing of muscles

withdrawal reflex

93

afferent sensory impulse synapses with interneurons crosses to other side of spinal cord and stimulates muscles that extend the opposite limb

crossed extender reflex

94

light tap on medial canthus of eye produces blind of eyelids, cranial nerve 5 and jaw tone

palpebral reflex

95

normal response to shining light in the eye of an animal is for iris in both eyes to constrict

pupillary light reflex (PLR)

96

what is another name for nerve fibers?

axons

97

as opposed to the nervous system, how does the endocrine system work?

it utilizes hormones to cause an effect in tissues

98

what part of the brain controls temperature regulation and thirst?

diencephalon

99

turning the head is an example of which nervous system?

somatic nervous system

100

in a repolarized neuron, where is the sodium and potassium the highest?

potassium is highest outside the cell and sodium is highest inside the cell

101

what is the name of the period when a neuron that normally generates a nerve impulse can not generate another?

refractory period

102

what part of the spinal cord carries afferent sensory fibers?

dorsal horn

103

what gland in the body produces a hormone that complements the action of the hormones produced by the sympathetic nervous system?

adrenal gland

104

what is the neurotransmitter for the parasympathetic nervous system?

acetylcholine

105

what are the two receptors of the parasympathetic nervous system?

nictorinic and muscarinic

106

what are the three receptors for the sympathetic nervous system and where are they found?

alpha - vasoconstriction of the gi tract
beta 1 - heart
beta 2 - bronchioldilation of the lungs

107

what neurotransmitter stimulates the gi tract?

acetylcholine

108

when the spinal cord is injured how will the nervous system caudal to the area of the the injury respond?

it will have an increased response so it will be hyper reflexive

109

what reflex results in both the ipsilateral and contralateral response

crossed extender reflex

110

what is the term used to convert a mechanical stimulus into an electrical stimulus that travels to the central nervous system?

transduction