Topic 9: CNS Tissue Flashcards Preview

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Flashcards in Topic 9: CNS Tissue Deck (90)
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0
Q

Signals that are carried away from the CNS by nerve fibers of PNS to innervate muscles to contract/or glands to secrete

A

Motor (efferent) neurons

1
Q

Signals carried by nerve fibers of PNS to CNS (picked up by sensory receptors throughout the body)

A

Sensory (afferent) neurons

2
Q

Basic organs/structures of the CNS

A
  • Brain

- Spinal Cord

3
Q

Function of the peripheral nervous system

A

to link all regions of the body to the CNS via nerves

4
Q

peripheral nerves that extend from the brain and carry signals to and from the brain

A

Cranial Nerves

5
Q

peripheral nerves that extend from the spinal cord and carry signals to and from the spinal cord

A

Spinal Nerves

6
Q

clusters of neuronal cell bodies located outside of the CNS

A

ganglia

7
Q

Basic components of the PNS

A
  • Cranial and Spinal nerves (peripheral nerves)

- ganglia

8
Q

Excitatory cells, basic structural unit of the nervous system

A

Neurons

9
Q

Function of neurons

A

conduct electrical impulses from one part of the body to another, rapid signals along the plasma membrane in the form of nerve impulses= action potentials

10
Q

3 main characteristics of neurons

A
  • Extreme longevity
  • No mitotic division
  • High metabolic rate
11
Q

components of a cell body

A
  • single nucleus
  • cytoplasm
  • chromatophilic bodies
  • neurofibrils
12
Q

location of cell bodies

A

in CNS, except for ganglia

13
Q

Function of a dendrite

A

receptive site for receiving signals from other neurons and transmitting signals towards cell body

14
Q

location where axons arise

A

axon hillock

15
Q

relationship between axon diameter and resistance of electrical current

A

inverse; increased axon diameter= decreased electrical current resistance which results in a faster impulse

16
Q

function of axon

A

impulse generator and conductor transmits impulses away from the cell body

17
Q

structural support components of axons

A
  • neurofilaments
  • actin microfilaments
  • microtubules
18
Q

axon branching developed at right angles

A

axon collaterals

19
Q

where does axon branching occur?

A

terminal branches

20
Q

Where do axons end?

A

axon terminals

21
Q

classification of neuron with >2 processes, multiple dendrites (extending from cell body) and 1 axon

A

Multipolar

22
Q

examples of multipolar nuerons?

A

Interneurons (mostly) & motor neurons

23
Q

classification of neuron with 2 processes, fused dendrite and one axon extend from opposite sides of the cell body

A

Bipolar

24
Q

example of bipolar neurons?

A

specialty sensory organs (e.g. inner ear, olfactory epithelium of the nose, retina of the eye)

25
Q

classification of neurons with one short single processes near cell body that divides into two branches (central= axon that extends to CNS) and (peripheral=dendrite that extends to periphery receptors)

A

Unipolar

26
Q

example of unipolar neurons?

A

dorsal root ganglia (along spinal cord) and sensory ganglia of cranial nerves

27
Q

what structural classification are sensory neurons?

A

unipolar neurons

28
Q

most abundant glial cell in the CNS

A

astrocytes

29
Q

glial cells that wrap around thin axons (unmyelinated) in the CNS

A

astrocytes

30
Q

glial cells with radiating processes with bulbous endings cling to neurons and/or capillaries

A

astrocytes

31
Q

glial cells that extract blood sugar from capillaries for energy in the CNS

A

astrocytes

32
Q

glial cells whose functions are sensing the release of NTs, regulating levels of NTS by increasing uptake, signal increased blood flow in capillaries in active regions of the brain, take up and release ions, develop neural tissue to form synapses tissue to form synapses, produce BDFT (neutral development), progagate calcium signals for memory

A

astrocytes

33
Q

glial cells in CNS that wrap around thicker axons

A

oligodendrocytes

34
Q

glial cells in CNS that produce myelin sheaths

A

oligodendrocytes

35
Q

smallest and least abundant glial cells in the CNS

A

microglial

36
Q

glial cells in CNS with elongated cell bodies and processes with pointy projections

A

microglial

37
Q

glial cells in CNS with phagocytes and are monocyte derived

A

microglial

38
Q

glial cells in CNS that support the maturation of synaptic clefts

A

microglial

39
Q

glial cells in CNS that are single epithelium that line central cavity of the brain and spinal cord

A

ependymal

40
Q

glial cells in CNS that form a permeable layer btw CSF and tissue fluid to bathe cells and have cilia to circulate CSF

A

ependymal

41
Q

disorder of the immune system attacking the myelin around axons in the CNS, woman are affected more, but develops quicker and more devastating in men

A

multiple sclerosis

42
Q

function of myelin sheath

A

insulating layer that prevents leakage of electrical current, and increases speed of impulse connection

43
Q

glial cells in PNS that surround cell bodies within ganglia

A

satellite cells

44
Q

glial cells in CNS that surround axons in the PNS and form myelin sheaths arround thick akons in concentric layers and contain neurilemma and nodes of ranvier

A

schwann cells

45
Q

outermost nucleated cytoplasmic layer of Schwann cells external to myelin sheath cells

A

neurilemma (sheath of schwann)

46
Q

gaps along the axon btw adjacent Schwann cells

A

Node of Ranvier

47
Q

which type of axon conduces impulses more slowly?

A

thin axons

48
Q

most common locations of thin axons

A

autonomic nervous system, sensory fibers

49
Q

membrane bound sacs that contain NTs

A

synaptic vesicles

50
Q

function of increased mitocondria in axon terminal?

A

provides energy for the secretion of NTs

51
Q

cable like structures in the PNS that consist of numerous parallel axons wrapped around in connective tissue

A

Nerves

52
Q

what are the main structures in a nerve?

A
  • schwann cells
  • endoneurium
  • nerve fascicles
  • epineurium
  • blood vessels
53
Q

layer of connective tissue covering schwann cells in a nerve

A

Endoneurium

54
Q

groups of axons bundled by a perineurium in a nerve

A

nerve fascicles

55
Q

tough, fibrous sheath surroundin nerves

A

epineurium

56
Q

location of gray matter

A

hollow central cavities of the CNS

57
Q

what is gray matter composed of?

A
  • clusters of neuron cell bodies
  • dendrites
  • short unmyelinated axon of interneurons
  • neuroglia cells
58
Q

what does the dorsal half of gray matter contain?

A

cell bodies of interneurons

59
Q

what does the ventral half of gray matter contain

A

cell bodies of motorneurons

60
Q

what gives white matter its color?

A

myelin

61
Q

what is white matter composed of?

A

bundles of myelinated axons

62
Q

2 main differences btw white and gray matter

A
  • gray matter has neural cell bodies and white matter lacks them
  • gray matter predominately unmyelinated and white matter has mostly myelianated axons
63
Q

function of gray matter interneurons

A
  • process and receive sensory information
  • direct information to specific CNS regions and or to cell bodies of motor neurons in ventral spine
  • initiate appropriate motor response
64
Q

function of white matter interneurons

A

transport information (sensory and motor) from one area of the CNS to another

65
Q

simple chains of neurons

A

reflex arcs

66
Q

rapid voluntary automatic motor response to stimuli

A

reflex

67
Q

two types of reflexes

A
  • somatic (skeletal muscle)

- visceral (smooth muscle, cardiac and glands)

68
Q

component of a reflex arc that is the terminal end of sensory nerve and where the stimulus acts

A

receptor

69
Q

component of a reflex arc that transmits afferent impulse to CNS

A

sensory neuron

70
Q

component of a reflex arc in which one or more synapses in gray matter (CNS) and is monosynaptic

A

integration center

71
Q

component of a reflex arc that conducts efferent impulses to an effector

A

motor neuron

72
Q

component of a reflex arc that is a muscle or gland that responds to efferent impulses by contraction or secretion

A

effector

73
Q

order of the reflex arc

A
  • receptor
  • sensory neuron
  • integration center
  • motor neuron
  • effector
74
Q

reflex composed of one sensory neuron + motor neuron + synapse
(no interneuron) and is fast

A

monosynaptic reflex

75
Q

example of a monosynaptic reflex?

A

stretch reflexes–knee jerk

76
Q

function of knee jerk reflex?

A

helps maintain equalibrium and upright posture

77
Q

reflex composed of one or more interneurons part pathway between sensory neurons and motor neurons

A

polysynaptic relfex

78
Q

example of a simple polysynaptic reflex?

A

withdrawal reflex

79
Q

how many interneurons, synapses and neurons does the withdrawal reflex have?

A
  • 1 interneuron
  • 2 synapses
  • 3 neurons
80
Q

neural circuit in which one presynaptic neuron synapses with multiple other neurons

A

Diverging Circuit

81
Q

neural circuit in which neurons synapse on a single postsynaptic neuron and a single motor neuron may receive both excitatory and inhibitory messages

A

Converging circuit

82
Q

neural circuit in which one neuron in the circuit receives feedback from another neuron in the same circuit

A

Reverberating circuit

83
Q

examples of what circuit are motor neurons that innervate the stretch muscles and stimulate contraction, interneurons that inhibit the activity of the antagonistic muscle groups, and interneurons that project sensory information to the brain

A

Diverging circuit

84
Q

example of reverberating circuits?

A

rhythmic activities e.g. breathing

85
Q

input processing in which neurons pass a signal to a specific destination in sequence along a single pathway from one neuron to the next

A

serial processing

86
Q

examples of serial processing

A
  • reflex arcs

- long chain of interneurons carrying a sensory signal to the brain

87
Q

path of the withdrawal reflex

A
  • nerve impulse travel to spinal white matter
  • extends as a ascending pathway to brain
  • integration in gray matter
  • voluntary motor response
88
Q

input processing in which single sensory stimulus results in multiple perceptions, single neuron is sent along two or more parallel pathways, sense multiple perceptions at once

A

parallel processing

89
Q

example of parallel processing

A

withdrawal reflex