E3 Ch. 12 Flashcards Preview

Anatomy > E3 Ch. 12 > Flashcards

Flashcards in E3 Ch. 12 Deck (100):
1

what are the 3 overlapping functions of the nervous system (NS)

1. sensory receptors monitor changes inside/outside the body
2. processes and interprets sensory input
3. dictates a response by activating effector organs

2

stimulus

changes detected inside or outside the body

3

sensory input

information gathered by receptors

4

integration

term for interpreting input

5

motor output

the response

6

what is the CNS composed of

brain and spinal cord

7

function of the CNS

integrating and command center

8

what does the PNS consist of

nerves extending from brain and spinal cord (cranial nerves, and spinal nerves)

9

ganglia

clusters of neuronal cell bodies

10

sensory

(afferent) signals picked up by sensory receptors, carried by nerve fibers of PNS to the CNS

11

motor

(efferent) signals carried away from CNS, innervates muscle and glands

12

what are the main divisions of sensory input and motor output

somatic and visceral body regions

13

what are the 4 main subdivisions of sensory input and motor output

somatic sensory, visceral sensory, somatic motor, and visceral motor (autonomic nervous system)

14

where do somatic sensory receptors spread to

receptors spread throughout outer tube of body

15

types of sense somatic sensory receptors receive

touch, pain, vibration, pressure, tempt.

16

proprioceptive senses

detect stretch in tendons and muscles, body senses position and movement of body in space

17

what are special somatic senses

hearing, balance, vision, smell

18

what are the general visceral senses

stretch, pain, tempt, nausea, and hunger, widely felt in digestive and urinary tracts, and reproductive organs

19

what are some special visceral senses

taste and smell

20

what do general somatic motor signal

contraction of skeletal muscles, under our voluntary control

21

brachial motor

typical skeletal muscles derived from somitomeres

22

what does visceral motor regulate

contraction of smooth and cardiac muscles, makes up autonomic NS

23

what are the two main cell types found in nervous tissue

neurons and support cells (neuroglial cells in CNS)

24

function of neurons

transmit electrical signals

25

function of support cells

surround and wrap neurons

26

describe the neuron

basic structural unit of the NS, specialized cells conduct electrical impulses along the PM (nerve impulse)

27

list the special characteristics of neurons

longevity, do not divide, high metabolic rate

28

chromatophilic bodies (nissl bodies)

clusters of rough ER and free ribosomes, function to renew membranes of the neurons

29

neurofibrils

bundles of intermediate filaments, form network b/t chromatophilic bodies

30

where are most neuronal cell bodies located

w/ in the CNS

31

what are the neuronal cell bodies in the PNS called

ganglia

32

dendrites

extensively branching from the cell body, transmit electrical signals toward the cell body

33

where do chromatophilic bodies extend to

into the basal part of dendrites and to the base of the axon hillock, function as receptive sites for receiving signals from other neurons

34

axon

impulse generater/conductor, transmits impulses away from cell body

35

what type of filaments are found in the axon and what do they provide

neurofilaments, actin microfilaments, and microtubules, provide strength along length of axon aid in axonal transport

36

axonal transport

transport of substances to and from the cell body

37

terminal arboration (telodendria)

multiple branches at end of axon

38

terminal boutons (axon terminals)

end knobs found at the ends of terminal arboration

39

where are nerve impulses generated

at the initial segment of the axon, conducted along axon to the terminal boutons

40

what is released at the terminal boutons

neurotransmitters from vesicles

41

synapses

site at which neurons communicate, most info. passed though chemical messenger

42

presynaptic neuron

conducts signal toward a synapse

43

postsynaptic neuron

transmits electrical activity away from a synapse

44

axodendritic

b/t axon terminals of one neuron and dendrites of another, most common type of synapse

45

axosomatic

b/t axons and neuronal cell bodies

46

synaptic vesicles on presynaptic side

membrane-bound sacs containing neurotransmitters, mitochondria abundant in axon terminals

47

synaptic cleft

separates PM of the two neurons

48

what are the 3 structural classifications of neurons

multipolar, bipolar, unipolar

49

multipolar neurons

possess more than two processes, numerous dendrites and one axon

50

bipolar neurons

possess two processes, rare neuron, found in some special sensory organs

51

unipolar (pseudounipolar)

possess one short, single process, start as bipolar neurons during development

52

what is the functional classification for neurons

according to the direction the nerve impulse travels relative to the CNS

53

what are 3 types of neurons

sensory, motor, interneurons

54

function of sensory neurons

transmit impulses toward CNS

55

what do the short, singles process of sensory neurons divide into

central process: runs centrally into the CNS, most are unipolar

peripheral process: extends peripherally to the receptors

56

function of motor (efferent) neurons

carry impulses away from CNS to effector organs, most are multipolar

57

interneurons

multipolar, lie b/t motor and sensory neurons, confined to the CNS

58

where are the 6 types of neuroglia found and what is their function

4 in CNS
2 in PNS
provide supportive functions for neurons and cover non synaptic regions of the neurons

59

function of astrocytes

keeps capillaries and neurons close, wraps around each and regulates which substances get released to neurons

60

what are microglia

smallest and least abundant glial cell, phagocytes-macrophages of CNS, engulf invading microorganisms/dead neurons.

61

where are microglia derived from

blood cells called monocytes

62

ependymal cells

line central cavity of spinal cord and brain, bear cilia-help circulate cerebrospinal fluid

63

oligodendrocytes

wrap their cell processes around axons in CNS, produce myelin sheaths in CNS

64

what are the different types of neuroglia in the CNS

astrocytes, microglia, ependymal cells, and oligodendrocytes

65

what are the different types of neuroglia in the PNS

satellite cells, and schwann cells

66

satellite cells

surround neuron cell bodies w/in ganglia

67

schwann cells (neurolemmocytes)

surround axons in the PNS, form myelin sheath around axons of the PNS

68

describe myelin sheaths

segmented structures composed of lipoprotein myelin, surround thicker axons forming an insulating layer that prevents leakage of electrical current, and increases speed of impulse conduction

69

myelin sheaths in the PNS are formed by what?

schwann cells

70

neurilemma

outer collar of perinuclear cytoplasm, material external to myelin layers

71

which types of axons (thin or thick) is myelinated and non-myelinated

thick= myelinated
thin=non-myelinated

72

where do oligodendrocytes form myelin sheaths

CNS

73

nerves

cable like organs in PNS consisting of numerous axons wrapped in connective tissue, most contain myelinated/nonmyelinated sensory and motor axons, which are surrounded by schwann cells

74

endoneurium

layer of delicate connective tissue surrounding the axon

75

perineurium

connective tissue wrapping surrounding a nerve fascicle

76

nerve fascicles

group of axons bound into bundles

77

epineurium

whole nerve is surrounded by tough fibrous sheath

78

what is gray matter composed of

primarily of neuronal cell bodies, dendrites, non-myelinated axons, surrounds white matter of CNS in cerebral cortex and cerebellum

79

what is what matter composed of

myelinated axon, lies external to gray matter of CNS, consists of axons passing b/t specific regions of CNS

80

tracts

bundles of axons traveling to similar destinations

81

what do afferent PNS fibers respond to

sensory stimuli

82

what do efferent PNS fibers do

transmit motor stimuli from CNS muscles and glands

83

what re the nerves of the CNS composed of and function

composed of interneurons that receive sensory info, direct/transport info to specific CNS regions, and initiate appropriate motor responses

84

reflex arcs

simple chains of neurons, responsible for reflexes, determine structural plan of the NS

85

reflexes

rapid, autonomic motor responses that can be visceral or somatic

86

what are the 5 parts to the reflex arcs

1. receptor- site where stimulus acts
2. sensory neuron- transmits afferent impulses to CNS
3. integration center-consists of one or more synapses in the CNS
4. motor neuron-conducts efferent impulses from integration center to affecter
5. effector-muscle or gland cell

87

monosynaptic reflex

"knee-jerk reflex" simplest and fastest of all reflexes, has just one synapse

88

polysynaptic reflex

one or more interneurons part of pathway, w/drawl reflexes, interneurons signal motor neuron to contract muscles involved

89

diverging circuit

one presynaptic neuron synapses w/ several other neurons

90

converging circuit

many neurons synapse on a single postsynaptic neuron

91

reverberating circuit

circuit that receives feedback via a collateral axon from a neuron in the circuit

92

list the different types of neuronal circuits

diverging, converging, and reverberating

93

list the different types of processing

serial and parallel processing

94

serial processing

neurons pass a signal to a specific destination along a single pathway from one to another

95

parallel processing

input is delivered along many pathways; a single sensory stimulus results in multiple perception

96

multiple sclerosis

autoimmune disease where immune system attacks myelin around axons in CNS, cause incompletely understood

97

neuronal regeneration

injuries may cause permanent dysfunction if axons alone are destroyed, cell bodies often survive and can regenerate axons

98

neuronal regeneration in the PNS

macrophages invade and destroy axon distal to injury, axon filaments grow peripherally from inured site, partial recovery sometimes possible

99

neuronal regeneration in the CNS

neuroglia never form bands to guide regrowing axons and may hinder axon growth w/ growth-inhibiting chemicals, no effective regeneration after injury to the spinal cord and brain

100

where does nervous system develop from

dorsal ectoderm, invaginates to form neural tube and neural crest, tube walls being as neuroepithelial cells which later divide and become neuroblasts