Lab Exam Three: Histology of Nervous Tissue Flashcards
1
Q
What does the CNS consist of?
A
brains and spinal cord enclosed and protected by the cranium and veterbrae column
2
Q
What does the PNS consist of?
A
nerves and ganglia
3
Q
What is a nerve?
A
a bundle of nerve fibers (axons) wrapped in fibrous connective tissue
4
Q
What is a ganglion?
A
knotlike swelling in a nerve, where the cell bodies of neurons are concentrated
5
Q
List the general coordination steps within the nervous system:
A
- Receiving
- Processing
- Issuing commands
6
Q
The CNS processes information received, […] with past […] and determines what […], if any,, is appropriate.
A
relates it; experiences; response
7
Q
The CNS issues commands primarily to […] and […] cells to carry out such responses.
A
muscle; glands
8
Q
The sensory […] division carries signals from […] to the […].
A
afferent; receptors: brain
9
Q
What two divisions are found within the afferent division?
A
- somatic sensory
2. visceral division
10
Q
The somatic sensory division carries the signal…
A
from receptors in the skin, muscles, bones and joints
11
Q
The visceral sensory division carries the signal…
A
mainly from the viscera of the thoracic and abdominal cavities
12
Q
The motor […] division carries signals from the […] to […] and […] cells […] that carry out the body’s responses.
A
efferent; CNS; gland; muscles; effectors
13
Q
The somatic motor division carries signals to the…
A
skeletal muscles
14
Q
What are the two responses delivered by the somatic nervous system? Are they involuntary or voluntary?
A
- muscle contraction (voluntary control)
2. somatic reflexes (involuntary control)
15
Q
The visceral motor division is also known as the….
A
autonomic nervous system (ANS)
16
Q
What three places does the ANS carry signals to?
A
- glands
- cardiac muscle
- smooth muscle
17
Q
The visceral motor division responses are known as […] these are […] done.
A
visceral reflexes; unconsiously
18
Q
What are the two subdivisions found in the ANS (visceral)?
A
- sympathetic division
2. parasympathetic division
19
Q
Sympathetic division tends to…
A
arouse the body for action
20
Q
Parasympathetic division tends to…
A
have a calming effect
21
Q
Neurosoma:
A
cell body of neuron that contains nucleus and organelles
22
Q
Dendrites:
A
branched processes that receive signals from other cells
23
Q
Neuroglia:
A
protect and assist the neurons
24
Q
Structure– On one side of the soma is a mound called the […], from which the […] originates
A
axon hillock; axon (nerve fiber)
25
What encloses the axon?
1. Schwann cells
| 2. myelin sheath
26
Structure-- What is a terminal arborization? Where can this be found?
extensive complex of fine branches
found at the distal end of an axon
27
Structure-- Each branch ends in a [...] (terminal button), a little swelling that contains synaptic [...] full of [...] , the swelling also forms a [...] with the next cell.
synaptic knob; vesicles; neurotransmitters; junction
28
What are the types of neurons?
1. multipolar
2. bipolar
3. unipolar
4. anaxonic
29
Have one axon and multiple dendrites:
multipolar neurons
30
Which type of neuron is the most common?
multipolar
31
Which type of neuron includes most neurons of the brain and spinal cord?
multipolar
32
Have one axon and one dendrite?
bipolar
33
What are some examples of bipolar neurons?
olfactory cells of the nasal cavity, certain neurons of the retina, and sensory neurons of the inner ear
34
Have only a single process leading away from the soma?
unipolar
35
An example of unipolar neurons:
neurons that carry sensory signals to the spinal cord
36
Have multiple dendrites but no axon?
anaxonic
37
Where can you find anaxonic neurons?
brain, retina, adrenal medulla
38
Which type of neurons communicate through their dendrites but do not produce action potentials?
axaonic
39
Glial cells [...] together and provide a [...] for the nervous tissue.
bind neurons; supportive framework
40
Whenever a [...] is not in synaptic contact with another cell, it is [...].
mature neuron; covered with glial cells
41
What is the purpose of covering mature neurons with glial cells?
prevents neurons from contacting each other except at points specialized for signal transmission
42
What are the the types of neuroglia?
1. oligodendrocytes
2. ependymal cells
3. microglia
4. astrocytes
5. Schwann cells
6. satellite cells
43
Which neuroglia are only part of the CNS?
4:
1. oligodendrocytes
2. ependymal cells
3. microglia
4. astrocytes
44
Oligodendrocytes:
(octopus) insulates the nerve fiber from the extracellular fluid (myelin sheath)
45
Ependymal cells:
resemble a cuboidal epithelium lining the internal cavities of the brain and spinal cord
46
Microglia:
small macrophages that develop from WBC called monocytes
47
Astrocytes:
(starlike) are the most abundant and constitute over 90% of the tissue in some areas of the brain
48
What are the functions of astrocytes?
1. they form supportive framework (blood-brain barrier)
| 2. scar tissue and fill space formerly occupied by damaged neurons astrocytosis/sclerosis
49
What are the types of neuroglia of the PNS?
1. Schwann cells (neurilemmocytes)
| 2. satellite cells
50
Schwann cells function:
1. produce myelin sheath
| 2. assist in the regeneration of damaged fibers
51
Satellite function:
1. provide electrical insulation around the soma
| 2. regulate the chemical environment of the neurons
52
Satellite cells:
surround the neurosomas in ganglia of the PNS
* *neurosomas = nerve cell bodies
* *ganglia = collection of neurosomas
53
What is the composition of the myelin sheath?
20% protein
| 80% lipid
54
Myelination:
production of the myelin sheath until completion in late adolescence
55
What are the two factors on the speed of nerve fibers?
1. diameter of the fiber
| 2. presence/absence of myelin
56
Signal conduction occurs...
along the surface of a fiber NOT deep within its axoplasm
57
Why do large fibers conduct signals more rapidly?
they have more surface area
58
How does myelin sheath factor in on conduction speed?
presence speeds up signal conduction
59
The cerebrum makes up [...] of the brain's volume and consists of a pair of [...].
83%; cerebral hemispheres
60
Gyri:
thick folds of the cerebrum
61
Sulci:
shallow grooves in the cerebrum
62
What marking separates the right and left hemispheres?
the longitudinal fissure
63
At the bottom of the longitudinal fissure what connects the hemispheres?
a thick bundle of nerve fibers called the corpus callosum
64
What is (are) the function(s) of the frontal lobe?
1. voluntary motor functions
2. motivation
3. foresight
4. planning
5. memory
6. mood
7. emotion
8. social judgment
9. aggression
65
What is (are) the function(s) of the parietal lobe?
1. primary site for receiving and interpreting signals of the general senses
66
What is (are) the function(s) of the occipital lobe?
1. principle visual center of the brain
67
What is (are) the function(s) of the temporal lobe?
1. hearing
2. smell
3. learning
4. memory
5. some aspects of vision and emotion
68
Insula:
small mass of the cortex deep to the lateral sulcus
**made visible only by retracting or cutting away some of the overlying cerebrum
69
What is the anatomic position of the cerebellum?
posterior cranial fossa, inferior to the cerebrum, separated from it by the transverse cerebral fissure
70
Cerebellum-- consists of right and left [...] connected by a narrow bridge called the [...].
cerebral hemispheres; vermis
71
Cerebellum- Each hemisphere exhibits folds called [...] separated by shallow [...].
folia; sulci
72
What are the most distinctive neurons within the cerebellum?
purkinje cells
73
How is the cerebellum connected to the brainstem?
cerebellar peduncles
74
What are the 3 portions of the cerebellar peduncles?
1. inferior peduncles
2. middle peduncles
3. superior peduncles
75
Inferior peduncles are connected to the [...] this is the [...] input.
medulla oblongata; spinal
76
Middle peduncles are connected to the [...] this is the [...] input.
pons; cerebral
77
Superior peduncles are connected to the [...] this is the [...] output.
midbrain; cerebellar
78
The white matter on the cerebellum exhibits a branching pattern called the [...].
arbor vitae
79
Cerebellum function:
center for monitoring muscle contractions and aiding in motor coordination
80
Gray matter:
the seat of the neurosomas, dendrites, and synapses
81
What does the gray matter form?
cortex (surface layer) and nuclei (deeper masses surrounded by white matter)
82
What does the gray matter cortex layer cover?
cerebrum and cerebellum
83
The brain is enveloped in three [...] tissue membranes: [...].
connective; meninges
84
What are the three meinges?
1. dura mater
2. arachnoid mater
3. pia mater
85
What are the functions for the meninges?
protect the brain and provide a structural framework for its arteries and veins
86
The dura mater consists of two layers:
1. outer periosteal layer
| 2. inner meningeal layer
87
An outer periosteal layer is equivalent to...
periosteum of the cranial bones
88
Dural sinuses:
spaces that collect blood that has circulated through the brain
89
What are the two dural sinuses?
1. superior sagittal sinus
| 2. transverse sinus
90
Superior sagittal sinus:
can be found under the cranium along the median line
91
Transverse sinus:
runs horizontally from the rear of the head toward each ear and empty into the internal jugular veins of the neck
92
The arachnoid mater:
transparent membrane over the brain surface
93
What are the spaces of separation for the pia?
below-- subarachnoid
| above-- subdural
94
The pia mater is [...], that closely follows all the [...] of the brain, even dipping into the [...].
very thin; contours; sulci
95
Meningitis:
inflammation of the meninges
**one of the most serious diseases of infancy and childhood
96
When does meningitis occur?
3 months and 2 years of age
97
What are the causes of meningitis?
variety of bacteria and viruses that invade the CNS by way of the nose and throat, often following respiratory, throat, or ear infections
98
Signs and symptoms include (meningitis):
high fever, stiff neck, drowsiness, intense headache, vomiting
99
What can meningitis cause?
swelling of the brain, cerebral hemorrhaging, and sometimes death within mere hours of the onset of symptoms
100
How is meningitis diagnosed?
spinal tap and extraction of the CBF for bacteria and WBCs
101
CSF-- On the floor or wall of each [...] is a mass of [...] called a [...].
ventricle; blood capillaries; choroid plexus
102
Ependyma:
type of neuroglia that resembles a cuboidal
103
CSF:
clear, colorless liquid that fills the ventricles and canals of the CNS and bathes its externals surface
104
CSF production begins with the [...] of [...] through the capillaries of the brain.
filtration; blood capillaries
105
The brains internal chambers are called ...
ventricles
106
List the 4 ventricles:
1. lateral ventricles (x2)
2. third ventricle
3. fourth ventricle
107
The largest are the [...], which form an [...] in each cerebral hemisphere.
lateral ventricles; arc
108
Through an [...], each lateral ventricle is connected to the [...], inferior to the [...].
interventricular foramen; third ventricle; corpus callosum
109
The [...] passes down the core of the [...] and leads to the [...], between the pons and cerebellum.
cerebral aqueduct; midbrain; fourth ventricle
110
What occurs to the overall ventricle structure when it forms the central canal?
the space narrows, allowing the extension through the medulla oblongata into the spinal cord
111
What is in high demand for neurons?
1. ATP
2. glucose
3. oxygen
** meaning blood supply
112
Loss of consciousness is due to...
10 second interruption in blood flow
113
Impair neural function is due to...
1-2 minute interruption
114
Irreversible brain damage is due to...
4 minutes without blood
115
Damaged brain tissue is essentially [...] and the brain therefore must be [...].
irreplaceable; well protected
116
How is the brain well protected? What does it consist of?
blood-brain barrier (BBB)
consists of tight junctions between the endothelial cells that form the capillary walls
117
List the substances that the BBS is highly permeable to:
water, glucose, lipid-soluble substances (O2, CO2, alcohol, caffeine, nicotine, anesthetics)
118
The brainstem major components:
1. midbrain
2. pons
3. medulla oblongata
119
The brainstem ends at the [...] magnum of the skull.
foramen magnum
120
The medulla oblongata begins at the [...] of the skull and ends at the [...] between the [...] and [...].
foramen magnum; groove; medulla; pons
121
T/F All nerve fibers connecting the brain to the spinal cord pass through the medulla
True
122
Nerve fibers that pass through the medulla are either [...] or [...].
ascending (sensory) and some are descending (motor) fibers
123
Pons is situated [...] to the medulla.
rostral
124
What connects the cerebellum to the pons and midbrain?
two pair of cerebellar peduncles
125
The pons exhibits continuations of the [...] (sleep, [...], posture).
reticular formation; respiration
126
Cranial nerves [...] to [...] begin or end in the pons.
V; VIII
127
Reticular formation:
1. loosely organized web of gray matter that run vertically through all levels of the brainstem
2. consists of more than 100 small neural networks
128
What are the functions of the reticular formation (5)?
1. somatic motor control
2. cardiovascular control
3. pain modulation
4. sleep and consciousness
5. habituation
129
Injury to the sleep and consciousness function of the reticular formation can result in...
irreversible coma
130
Somatic motor control:
muscle tension to maintain tone, balance, and posture
131
Habituation:
the brain learns to ignore repetitive, inconsequential stimuli
132
Each side of the brain has a [...] (ovoid mass).
thalamus
133
Nearly all input to the cerebrum passes by way of synapses in the [...].
thalamic nuclei
134
What plays a key role in motor control? How does it accomplish this?
thalamus
signals from the cerebellum to the cerebrum
135
The thalamus is involved in the [...] and [...] functions of the limbic system ([...] and [...] lobes)
memory; emotional; temporal; frontal
136
What does the hypothalamus form?
floor and part of the walls of the 3rd ventricle
137
What is the range of the hypothalamus?
from the optic chiasm to the mammillary bodies
138
The [...] is attached to the hypothalamus by a stalk ([...]).
pituitary gland; infundibulum
139
Hypothalamus is the major control center of the [...] and [...] due to its [...].
endocrine; autonomic nervous system; homeostasis regulation
140
What are ways that shows the homeostatic regulation of the thalamus?
1. hormone secretion
2. autonomic effects
3. thermoregulation
4. food and water intake
5. sleep and circadian rhythms
6. memory
7. emotional behavior and sexual response
141
Epithalamus:
very small mass of tissue
142
Epithalamus is composed of...
1. pineal gland
2. habenula
3. thin roof over the 3rd ventricle
143
The pineal gland is associated with...
circadian rhythyms
144
The habenula is a [...] from the limbic system to the [...].
relay; midbrain
