Nervous System Flashcards
(89 cards)
1
Q
o Enclosed by the skull
o Contains about 100 billion neurons
A
Brain
2
Q
o Twelve pairs (right and left) of cranial nerves, numbered I through XII,
emerge from the base of the brain.
A
Cranial nerves
3
Q
a bundle of hundreds to thousands of axons plus associated
connective tissue and blood vessels that lies outside the brain and spinal
cord.
A
nerve
4
Q
o Connects to the brain through the foramen magnum of the skull and is encircled by the bones of the vertebral column. o It contains about 100 million neurons.
A
Spinal cord
5
Q
o Thirty-one pairs of spinal nerves emerge from the spinal cord, each serving a specific region on the right or left side of the
body.
A
Spinal nerves and their
branches
6
Q
o Small masses of nervous tissue, consisting primarily of neuron cell bodies,
that are located outside the brain and spinal cord.
o closely associated with cranial and spinal nerves.
A
Ganglia
7
Q
o In the walls of organs of the gastrointestinal tract, extensive networks of neurons
o help regulate the digestive system.
A
Enteric plexuses
8
Q
o Dendrites of sensory neurons as well as separate, specialized cells that
monitor changes in the internal or external environment, such as
photoreceptors in the retina of the eye.
A
Sensory receptors
9
Q
detect internal stimuli, such as an increase in blood acidity, and external stimuli
A
Sensory receptors
10
Q
o possess electrical excitability, the ability to respond to a stimulus and convert it into an action potential.
A
Neurons
11
Q
neurons three parts:
A
cell body
dendrites
axon
12
Q
Contains a nucleus surrounded by cytoplasm that includes typical cellular organelles such as lysosomes, mitochondria, and a Golgi complex.
A
Cell body
13
Q
▪ The receiving or input portions of a neuron.
▪ They usually are short, tapering, and highly branched.
A
Dendrites
14
Q
▪ Propagates nerve impulses toward
another neuron, a muscle fiber, or a
gland cell.
▪ Long, thin, cylindrical projection
A
Axon
15
Q
o Make up about half the volume of the CNS.
o Smaller than neurons, and they are 5 to 50 times more numerous.
o do not generate or propagate action potentials, and they can multiply and divide in the mature nervous system.
A
Neuroglia/ glia
16
Q
Brain tumors derived from glia
A
gliomas
17
Q
CNS types of neuroglia
A
astrocytes, oligodendrocytes,
microglia, and ependymal cells
18
Q
PNS types of neuroglia
A
Schwann cells and satellite cells
19
Q
Axons surrounded by a multilayered lipid and protein covering
A
myelin sheath, “myelinated”
20
Q
Axons surrounded by a multilayered lipid and without protein covering
A
unmyelinated
21
Q
Two types of neuroglia produce myelin sheaths
A
Schwann cells (in the PNS) Oligodendrocytes (in the CNS)
22
Q
The outer nucleated cytoplasmic layer of the Schwann cell, which encloses the myelin sheath
A
neurolemma (sheath of
Schwann)
23
Q
Gaps in the myelin sheath, appear at
intervals along the axon
A
nodes of Ranvier
24
Q
a bundle of axons that is located in the CNS.
A
tract
25
composed primarily of myelinated axons. The whitish color
| of myelin gives white matter its name.
White matter
26
appears grayish and contains
neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and
neuroglia.
gray matter
27
o Consists of the brain and spinal cord. o/processes many different kinds of incoming sensory information.
o It is also the source of thoughts,
emotions, and memories.
o contains most nerve impulses that stimulate muscles to contract and glands to secrete
Central Nervous System
28
o Includes all nervous tissue outside the CNS.
o Components include cranial nerves and their branches, spinal
nerves and their branches, ganglia, and sensory receptors.
Peripheral Nervous System
29
Consists of (1) sensory neurons that convey information from
somatic receptors in the head, body wall, and limbs and from
receptors for the special senses of vision, hearing, taste, and smell
to the CNS and (2) motor neurons that conduct impulses from the
CNS to skeletal muscles only. Because these motor responses can be consciously controlled, the action of this part of the PNS is
voluntary.
Somatic nervous system (SNS)
30
▪ Consists of (1) sensory neurons that convey information from
autonomic sensory receptors, located primarily in visceral organs
such as the stomach and lungs, to the CNS, and (2) motor neurons
that conduct nerve impulses from the CNS to smooth muscle,
cardiac muscle, and glands. Because its motor responses are not
normally under conscious control, the action of the ANS is
involuntary.
▪ The motor part consists of two branches, the sympathetic division and the parasympathetic division.
Autonomic nervous system (ANS)
31
the “brain of the gut,” is involuntary.
▪ Consists of approximately 100 million neurons in enteric plexuses
that extend most of the length of the gastrointestinal (GI) tract.
▪ chemical changes within the GI tract as well as the stretching of its walls. Enteric motor neurons
govern contraction of GI tract smooth muscle to propel food
Enteric nervous system (ENS)
32
Two types of connective tissue coverings of spinal cord
coverings—bony vertebrae and tough,
| connective tissue meninges—plus a cushion of cerebrospinal fluid
33
located within the vertebral canal of the vertebral column.
spinal cord
34
three connective tissue coverings that encircle the spinal cord and brain.
surround the spinal cord and
are continuous with the cranial meninges, which encircle the brain.
Meninges
a. Dura mater
b) Arachnoid mater
c) Pia Mater
35
▪ Most superficial of the three spinal meninges
▪ Composed of dense, irregular
connective tissue.
Dura mater
36
a space between the dura mater and the wall of the vertebral canal.
where cushion of fat and connective tissue is
located
epidural space
37
▪ Middle meninx (singular form of
meninges)
▪ Avascular covering composed of
collagen fibers and some elastic fibers.
Arachnoid mater
38
thin space which contains interstitial fluid. Between the dura mater and the arachnoid mater
subdural space
39
▪ Innermost meninx
▪ a thin transparent connective tissue layer that adheres to the surface of the spinal cord and brain.
▪ It consists of squamous to cuboidal cells within interlacing bundles of collagen fibers and some fine elastic fibers.
Pia Mater
40
▪ the paths of communication between the spinal cord and specific regions of the body.
appears to be segmented because ▪ the 31 pairs of spinal nerves emerge at regular intervals from intervertebral foramina.
Spinal nerves
41
the roots of nerves, “horse’s tail”
cauda equina
42
Two grooves penetrate the white matter of the spinal cord and divide it into right and left sides.
anterior median fissure
| posterior median sulcus
43
wide groove on the anterior
| (ventral) side.
anterior median fissure
44
narrow furrow on the
| posterior (dorsal) side.
posterior median sulcus
45
shaped like the letter H or a butterfly;
| it consists of dendrites and cell bodies of neurons, unmyelinated axons,band neuroglia.
gray matter
46
forms the crossbar of the H.
gray commissure
47
In the center of the gray commissure, small space
; it extends the entire length of the spinal cord and is
filled with cerebrospinal fluid.
central canal
48
Anterior to the gray commissure;
connects the white matter of the right and left sides of the spinal
cord.
anterior (ventral) white commissure
49
the regions of gray matter on each side of the spinal cord
horns
50
contain cell bodies and axons of
| interneurons as well as axons of incoming sensory neurons.
posterior (dorsal) gray horns
51
gray matter between the posterior and anterior gray horns, which are present only in thoracic and upper lumbar segments of the spinal cord.
lateral
| gray horns
52
the three broad areas, anterior and posterior gray horns divide the white matter on each side into:
columns: (1)anterior (ventral) white columns, (2)posterior (dorsal) white columns, and (3)
lateral white columns.
53
consist of axons that conduct nerve impulses toward the brain.
Sensory (ascending) tracts
54
Tracts consisting of axons that carry
| nerve impulses from the brain
motor (descending) tracts
55
adult brain consists of four major
| parts:
brain stem, cerebellum,
| diencephalon, and cerebrum.
56
is continuous with the
| spinal cord and consists of the medulla oblongata, pons, and midbrain.
brain stem
57
Posterior to the brain stem is the
cerebellum
58
Superior to the brain stem, ] consists of the thalamus, hypothalamus, and
epithalamus.
diencephalon
59
continuous with the spinal meninges, have the same
| basic structure, and bear the same names: the outer dura mater, the middle arachnoid mater, and the inner pia mater
cranial meninges
60
Three extensions of the dura mater separate parts of the brain:
Falx cerebri
Falx cerebelli
Tentorium cerebelli
61
Separates the two hemispheres (sides) of the cerebrum.
Falx cerebri
62
Separates the two hemispheres of the cerebellum.
Falx cerebelli
63
Separates the cerebrum from the cerebellum.
Tentorium cerebelli
64
arteries where blood flows to the brain
internal carotid and vertebral arteries
65
vein that return blood from the head to the heart
internal jugular veins
66
protects brain cells from harmful
substances and pathogens by preventing passage of many substances from blood
into brain tissue.
mainly of tight junctions that seal together the
endothelial cells of brain capillaries, along with a thick basement membrane around
the capillaries.
blood–brain barrier (BBB)
67
clear, colorless liquid that protects the brain and spinal cord from chemical and physical injuries. It also carries oxygen, glucose, and other needed chemicals from the blood to neurons and neuroglia.
continuously
circulates through cavities in the brain and spinal cord and around the brain and
spinal cord in the subarachnoid space (between the arachnoid mater and pia
mater).
Cerebrospinal fluid (CSF)
68
four CSF-filled cavities within the brain
```
ventricles
-lateral ventricle
-septum
pellucidum
-third ventricle
-fourth ventricle
```
69
ventricle located in each hemisphere of the cerebrum.
lateral ventricle
70
Anteriorly, the lateral ventricles are separated by a thin membrane, called
septum
| pellucidum.
71
ventricle that is a narrow cavity along the midline superior to the
hypothalamus and between the right and left halves of the thalamus.
third ventricle
72
ventricle that lies between the brain stem and the cerebellum.
fourth ventricle
73
sites of CSF production, networks of blood capillaries (microscopic blood vessels) in the walls of the ventricles.
choroid plexuses
74
where the CSF formed in the choroid plexuses of each lateral ventricle flows into the third ventricle through two narrow, oval openings called
interventricular
| foramina
75
part of the brain between the spinal cord and the diencephalon. It consists of three structures: (1) medulla oblongata, (2) pons, and (3) midbrain.
brain stem
76
parts of brain stem
(1) medulla oblongata, (2) pons, and
| (3) midbrain
77
continuous with the superior
part of the spinal cord; it forms the inferior part of the brain stem.
begins at the foramen magnum and extends to the inferior border of
the pons.
medulla oblongata
78
regulates the rate and force of the heartbeat and the diameter of blood vessels.
cardiovascular center
79
adjusts the basic rhythm of breathing.
medullary rhythmicity area of the respiratory center
80
control reflexes for vomiting, swallowing, sneezing,
| coughing, and hiccupping.
Nuclei in the medulla
81
lies directly superior to the medulla and anterior to the cerebellum.
pons
82
extends from the pons to the diencephalon.
midbrain or mesencephalon
83
the anterior part of the midbrain contains paired bundles of axons;
conduct nerve impulses from motor
areas in the cerebral cortex to the spinal cord, pons, and medulla.
cerebral peduncles
84
posterior part of the midbrain, contains four
| rounded elevations.
tectum
85
two superior elevations, nuclei, serve as reflex centers for certain visual activities.\
also responsible for reflexes that govern movements of
the head, eyes, and trunk in response to visual stimuli.
superior colliculi
86
two inferior elevations, part of the
auditory pathway, relaying impulses from the receptors for hearing
in the inner ear to the brain. These two nuclei are also reflex centers
for the startle reflex, sudden movements of the head, eyes, and
trunk that occur when you are surprised by a loud noise such as a
gunshot.
inferior colliculi
87
midbrain nuclei, large and darkly pigmented, help control subconscious muscle activities. Loss of these neurons
is associated with Parkinson disease.
left and right substantia nigra
88
midbrain nuclei; look reddish due to their rich blood supply and an iron-containing pigment in their neuronal
cell bodies, help control some voluntary movements of the limbs.
left and right red nuclei
89
Still other nuclei in the midbrain are associated with two pairs of cranial
nerves:
oculomotor (III) nerves and trochlear (IV) nerves
