E3 Ch. 12 Flashcards
(100 cards)
1
Q
what are the 3 overlapping functions of the nervous system (NS)
A
- sensory receptors monitor changes inside/outside the body
- processes and interprets sensory input
- dictates a response by activating effector organs
2
Q
stimulus
A
changes detected inside or outside the body
3
Q
sensory input
A
information gathered by receptors
4
Q
integration
A
term for interpreting input
5
Q
motor output
A
the response
6
Q
what is the CNS composed of
A
brain and spinal cord
7
Q
function of the CNS
A
integrating and command center
8
Q
what does the PNS consist of
A
nerves extending from brain and spinal cord (cranial nerves, and spinal nerves)
9
Q
ganglia
A
clusters of neuronal cell bodies
10
Q
sensory
A
(afferent) signals picked up by sensory receptors, carried by nerve fibers of PNS to the CNS
11
Q
motor
A
(efferent) signals carried away from CNS, innervates muscle and glands
12
Q
what are the main divisions of sensory input and motor output
A
somatic and visceral body regions
13
Q
what are the 4 main subdivisions of sensory input and motor output
A
somatic sensory, visceral sensory, somatic motor, and visceral motor (autonomic nervous system)
14
Q
where do somatic sensory receptors spread to
A
receptors spread throughout outer tube of body
15
Q
types of sense somatic sensory receptors receive
A
touch, pain, vibration, pressure, tempt.
16
Q
proprioceptive senses
A
detect stretch in tendons and muscles, body senses position and movement of body in space
17
Q
what are special somatic senses
A
hearing, balance, vision, smell
18
Q
what are the general visceral senses
A
stretch, pain, tempt, nausea, and hunger, widely felt in digestive and urinary tracts, and reproductive organs
19
Q
what are some special visceral senses
A
taste and smell
20
Q
what do general somatic motor signal
A
contraction of skeletal muscles, under our voluntary control
21
Q
brachial motor
A
typical skeletal muscles derived from somitomeres
22
Q
what does visceral motor regulate
A
contraction of smooth and cardiac muscles, makes up autonomic NS
23
Q
what are the two main cell types found in nervous tissue
A
neurons and support cells (neuroglial cells in CNS)
24
Q
function of neurons
A
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
