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Flashcards in Exam 1 Deck (94):
1

___ and ___ are the cells that form nervous tissue

neurons and neuroglia

2

three basic functions through which the nervous system integrates body activity

sensory
integrative
motor

3

involves detecting internal and external stimuli

sensory function

4

involves processing of sensory information

integrative function

5

occurs when the nervous system elicits a response by activating effectors

motor function

6

effectors =

muscles and glands

7

the CNS consists of the

brain and spinal cord

8

the ___ is responsible for integration of incoming sensory information, generation of motor commands, and thoughts and memories

central nervous system

9

the PNS is composed of

cranial and spinal nerves, ganglia, and sensory receptors

10

subdivisions of the PNS include the

somatic nervous system, autonomic nervous system, enteric nervous system

11

the ___ consists of sensory neurons that conduct impulses from somatic and special sense receptors to the CNS

somatic nervous system

12

the somatic nervous system also has motor neurons that innervate skeletal muscles under ___ control

voluntary

13

the ____ consists of sensory neurons that conduct impulses from visceral organs to the CNS and motor neurons that convey impulses from the CNS to smooth muscle tissue, cardiac muscle tissue, and glands

autonomic nervous system

14

the ___ consists of neurons in enteric plexuses in the GI tract that function somewhat independently of the ANS and CNS

enteric nervous system

15

the enteric nervous system monitors sensory changes in and controls operation of the ___

GI tract

16

three parts to most neurons include:

cell body, dendrites, axons

17

the ___ houses the nucleus surrounded by cytoplasm

cell body

18

organelles such as rough endoplasmic reticulum

Nissl bodies

19

processes that receive incoming impulses

dendrites

20

conducts impulses away from the cell body toward another neuron, muscle fiber, or gland cell

axon

21

where the axon joins the cell body

axon hillock

22

side branches of an axon

axon collaterals

23

the axon's cytoplasm

axoplasm

24

numerous fine processes at the ends of an axon and it collaterals

axon terminals

25

swollen tips of axon terminals where communication occurs between the neuron and other cells

synaptic end bulbs

26

newly synthesized cell products move by ____ or forward from the cell body toward the axon

anterograde transport

27

materials for recycling and degradation move from the axon to the cell body by ____

retrograde transport

28

neurons can be classified by structure as

multipolar, bipolar, or unipolar

29

several dendrites and one axon

multipolar

30

one dendrite and one axon

bipolar

31

one process arising from the cell body that branches into two axon-like processes

unipolar

32

neurons are functionally classified as

sensory, motor, and interneurons

33

sensory=

afferent

34

motor=

efferent

35

carry information into the CNS

sensory neurons

36

carry information out of the CNS to effectors

motor neurons

37

located within the CNS and integrate incoming sensory information from sensory neurons then elicit a motor response by activating motor neurons

interneurons

38

smaller and more numerous than neurons; can divide but cannot conduct impulses

neuroglia

39

neuroglia in the CNS include

astrocytes, oligodendrocytes, microglia, and ependymal cells

40

neuroglia in the PNS include

Schwann cells and satellite cells

41

multilayered lipid and protein covering produced by layers of plasma membrane from neuroglia that wrap around axons

myelin sheath

42

in the PNS ____ forms myelin sheath

Schwann cells

43

in the CNS ____form myelin sheath

oligodendrocytes

44

the unmyelinated gaps occurring at intervals along an axon are called ___

Nodes of Ranvier

45

the outermost nucleated layer of the Schwann cell that encloses the myelin sheath and functions in regeneration of damaged PNS axons

neurolemma

46

nervous system ____ appears this color due to the presence of myelinated axons

white matter

47

the ____ is composed of unmyelinated axons, cell bodies, and neuroglia

gray matter

48

neurons communicate by electrical signals called ___ over short distances or by ____ over longer distances

graded potentials
action potentials

49

nerve action potentials occur in ____

neurons

50

muscle action potentials occur in ____

muscle fibers

51

graded potentials occur in sensory receptors, dendrites, and cell bodies which allow axons to form action potentials resulting in release of _____

neurotransmitters

52

excitable cell plasma membranes have a _____ due to an electrical voltage difference across the membrane established by specific ion channels

resting membrane potential

53

____ open and close in response to specific stimuli

gated ion channels

54

four types of ion channels

leak channels
ligand-gated channels
mechanically gated channels
voltage-gated channels

55

open and close due to a chemical stimulus in which ligand binds to a membrane receptor

ligand-gated channel

56

open and close due to mechanical stimulation

mechanically gated channels

57

have alternating open and closes gates

leak channels

58

open when the membrane potential changes and participate in action potentials

voltage gated channels

59

the resting membrane potential is more negative along the ____ side of the plasma membrane and more positive along the _____ side of the membrane

cytosol
extracellular fluid

60

a cell with a membrane potential, such as a neuron, is considered ____

polarized

61

neurons typically have a resting membrane potential of ___

-70 mV

62

the opening and closing of ligand-gated and mechanically gated channels in response to a stimulus produces ____

graded potentials

63

____ result in a less polarized membrane

depolarizing graded potentials

64

____ result in an even more polarized membrane, or the membrane being more negative

hyperpolarized graded potentials

65

rapid electrical events occurring in two phases

action potentials

66

once threshold depolarization occurs, voltage-gated channels open, and an action potential that is always the same size occurs

all-or-none principle

67

during ____ the voltage gated Na channels quickly open, Na rushes into the cell, and the membrane potential becomes positive

depolarizing phase

68

during ____ voltage-gated K channels slowly open, K flows out of the cell and the membrane is repolarized

repolarizing phase

69

following an action potential there is a ____ during which an excitable cell cannot generate another action potential

refractory period

70

____ is the time when even a very strong stimulus cannot generate a second action potential

absolute refractory period

71

_____ a very strong stimulus can initiate a second action potential

relative refectory period

72

when Na flows into open channels in one area of the membrane, voltage-gated Na channels in adjacent segments of the membrane open resulting in _____ of the impulse toward the axon terminals

impulse propagation

73

myelinated axons undergo ____ in which Na and K flow across the membrane only at the unmyelinated nodes of ranvier as the impulse leaps from one node to another

saltatory conduction

74

impulses are conducted at a faster pace along ___ diameter axons

larger

75

____ permit communication over long distances

action potentials

76

____ function only in short distance communication

graded potentials

77

the ___ is the junction where communication occurs between two neurons or a neuron and an effector cell

synapse

78

_____ conduct impulses from a neuron to another cell through a synaptic cleft

chemical synapses

79

an impulse in presynaptic axon opens Ca channels in synaptic end bulbs, leading to release of neurotransmitter that crosses the synaptic cleft and binds to postsynaptic neuron receptors causing a ___

postsynaptic potential

80

_____ conduct impulses from a neuron to another cell through gap junction

electrical synapses

81

electrical synapses are common in visceral ___ and ____ muscle

smooth and cardiac

82

some neurotransmitters will depolarize the postsynaptic neuron's membrane to produce a ____

excitatory postsynaptic potential

83

some neurotransmitters will hyperpolarize the postsynaptic neuron's membrane to produce a _____ moving the membrane potential farther from threshold

inhibitory postsynaptic potential

84

_____ of a postsynaptic potentials determine whether the postsynaptic neuron will generate an action potential

summation

85

neurotransmitter is removed from the synaptic cleft by ____, ____, or ______

diffusion
enzymatic degradation
cellular uptake

86

the capability to change based on experience

plasticity

87

the capability to replace or repair destroyed cells

regeneration

88

degeneration of the distal portion of the axon and myelin sheath is called

wallerian degeneration

89

formed by Schwann cells directs passage of the regenerating axon to previously contacted receptors and effectors

regeneration tube

90

the CNS is made up of

brain and spinal cord

91

the largest part of the brain

cerebrum

92

contains the thalamus and hypothalamus

diencephalon

93

consists of the midbrain, pons, and medulla oblongata

brain stem

94

posterior to the brain stem is the ____

cerebellum