Structure of the Nervous System Flashcards
1
Q
How much of blood flow does the brain receive?
A
20%
2
Q
cerebrospinal fluid (CSF)
A
A clear fluid, similar to blood plasma, that fills the ventricular system of the brain and the subarachnoid space surrounding the brain and spinal cord.
3
Q
neuraxis
A
An imaginary line drawn through the center of the length of the central nervous system, from the bottom of the spinal cord to the front of the forebrain.
4
Q
anterior
A
With respect to the central nervous system, located near or toward the head.
5
Q
posterior
A
With respect to the central nervous system, located near or toward the tail.
6
Q
rostral
A
“Toward the beak”; with respect to the central nervous system, in a direction along the neuraxis toward the front of the face
7
Q
caudal
A
“Toward the tail”; with respect to the central nervous system, in a direction along the neuraxis away from the front of the face.
8
Q
dorsal
A
“Toward the back”; with respect to the central nervous system, in a direc- tion perpendicular to the neuraxis toward the top of the head or the back.
9
Q
ventral
A
“Toward the belly”; with respect to the central nervous system, in a direc- tion perpendicular to the neuraxis toward the bottom of the skull or the front surface of the body.
10
Q
lateral
A
Toward the side of the body, away from the middle.
11
Q
medial
A
Toward the middle of the body, away from the side.
12
Q
ipsilateral
A
Located on the same side of the body.
13
Q
contralateral
A
Located on the opposite side of the body.
14
Q
cross section
A
With respect to the central nervous system, a slice taken at right angles to the neuraxis.
15
Q
frontal section
A
A slice through the brain parallel to the forehead.
16
Q
horizontal section
A
A slice through the brain parallel to the ground.
17
Q
sagittal section
A
A slice through the brain parallel to the neuraxis and perpendicular to the ground.
18
Q
midsagittal plane
A
The plane through the neuraxis perpendicular to the ground; divides the brain into two symmetrical halves.
19
Q
meninges
A
The three layers of tissue that encase the central nervous system: the dura mater, arachnoid membrane, and pia mater.
20
Q
dura mater
A
The outermost of the meninges; tough and flexible.
21
Q
arachnoid membrane
A
The middle layer of the meninges, located between the outer dura mater (beneath) and inner pia mater. Soft and spongey. Weblike.
22
Q
pia mater
A
The layer of the meninges that clings to the surface of the brain; thin and delicate.
The smaller surface blood vessels of the brain and spinal cord are contained within this layer.
23
Q
subarachnoid space
A
The fluid-filled space that cushions the brain; located between the arachnoid membrane and the pia mater.
24
Q
meninges in PNS
A
- covered in two layers
- no arachnoid membrane
25
ventricle
One of the hollow spaces within the brain, filled with cerebrospinal fluid.
26
lateral ventricle
One of the two ventricles located in the center of the telencephalon. Largest chamber
27
third ventricle
The ventricle located in the center of the diencephalon.
28
cerebral aqueduct
A narrow tube inter- connecting the third and fourth ventricles of the brain, located in the center of the mesencephalon.
29
fourth ventricle
The ventricle located between the cerebellum and the dorsal pons, in the center of the metencephalon.
30
Function of ventricles
produce and contain CSF
31
choroid plexus
The highly vascular tissue that protrudes into the ventricles and produces cerebrospinal fluid.
32
arachnoid granulation
Small projections of the arachnoid membrane through the dura mater into the superior sagittal sinus; CSF flows through them to be reabsorbed into the blood supply.
33
weight of human brain vs. net weight in fluid
1400 g vs. 80 g
34
Purpose of the CSF
reduced pressure on base of brain & reduces shock to CNS caused by sudden head movement
35
forebrain
The most rostral of the three major divisions of the brain; includes the telencephalon and diencephalon.
36
Subdivisions of brain
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Telencephalon (cerebral cortex, basal ganglia, limbic system)
Diencephalon (thalamus, hypothalamus)
Mesencephalon (tectum, tegmentum)
Metencephalon (cerebellum, pons)
Myelencephalon (medulla oblongata)
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37
Telencephalon
includes most of cerebral hemispheres (cerebrum)
38
cerebral hemisphere
One of the two major portions of the forebrain, covered by the cerebral cortex.
39
cerebrum
Consists of the two cerebral hemispheres
40
subcortical region
The region located within the brain, beneath the cortical surface.
41
Cerebral Cortex
- surrounds the cerebral hemispheres
- consists of sulci(groove), fissures, gyri(convolution)
- referred as gray matter (because of so many cell bodies)
- under cerebral cortex is white matter (axons/large concentration of myelin)
42
Why is the brain not soft but with convolutions?
- triples surface area of cerebral cortex (2360 cm2 / 2.5 ft2) (thickness ~ 3mm)
43
Lobes of the cerebral cortex
frontal, parietal, temporal, occipital
44
Sensory Cortex
Three areas of the cerebral cortex that receive information from the sensory organs.
45
primary visual cortex
receives visual information, is located in the occipital lobe , primarily on the upper and lower banks of the calcarine fissure
46
primary auditory cortex
receives auditory information, is located in the temporal lobes, on the lower surface of the lateral fissure
47
primary somatosensory cortex
receives info from body senses, located on vertical strip of cortex just caudal to the central sulcus in the parietal lobe
- base + insular cortex --> taste
48
Which sensory information is not sent contralaterally?
olfaction (smell) & gustation (taste)
49
Rostral region functions
movement related activities, like planning and executing behaviour
50
Caudal region functions
perceiving and learning
51
sensory association cortex
Those regions of the cerebral cortex that receive information from the regions of the primary sensory cortex.
52
Damage to sensory association cortex
deficits are related to somatosensation and to the environment in general
- difficulty perceiving and understanding and remembering sensory stimuli
53
primary motor cortex
The region of the posterior frontal lobe that contains neurons that control movements of skeletal muscles.
54
motor association cortex
The region of the frontal lobe rostral to the primary motor cortex; also known as the premotor cortex. Controls primary motor cortex (behaviour)
55
prefrontal cortex
The region of the frontal lobe rostral to the motor association cortex; involved in formulating plans and strategies
56
Left hemisphere
- analysis of info
- recognizing serial events + controlling sequences of behaviour
- verbal activities (talking and understanding speech), reading, and writing
57
Right hemisphere
- synthesis
- putting isolated elements together and perceiving things as a whole
- drawing, reading maps, contruction
58
corpus callosum
A large bundle of axons that interconnects corresponding regions of the association cortex on each side of the brain.
59
limbic cortex
Phylogenetically old cortex, located at the medial edge (“limbus”) of the cerebral hemispheres; part of the limbic system.
60
cingulate gyrus
A strip of limbic cortex lying along the lateral walls of the groove separating the cerebral hemi- spheres, just above the corpus callosum.
61
limbic system
A group of brain regions including the anterior thalamic nuclei, amygdala, hippocampus, limbic cortex, and parts of the hypothalamus, as well as their interconnecting fiber bundles.
62
hippocampus
A forebrain structure of the temporal lobe, constituting an important part of the limbic system. Involved in learning and memory
63
amygdala
A structure in the interior of the rostral temporal lobe, contain- ing a set of nuclei; part of the limbic system.
- involved in emotions: feelings and expressions of emotions, emotional memories, and recognition of the signs of emotions in other people
64
fornix
Afiberbundlethatconnectsthe hippocampus with other parts of the brain, including the mammillary bodies of the hypothalamus; part of the limbic system.
65
mammillary bodies
A protrusion of the bottom of the brain at the posterior end of the hypothalamus, containing some hypothalamic nuclei; part of the limbic system.
66
basal ganglia
A group of subcortical nuclei in the telencephalon, the caudate nucleus, the globus pallidus, and the putamen; important parts of the motor system.
67
Major parts of basal ganglia
caudate nucleus, the putamen, and the globus pallidus
68
Parkinson's disease
caused by degeneration of neurons located in midbrain that send axons to caudate nucleus and putamen of basal ganglia
69
Diencephalon
surrounds third ventricle
70
thalamus
The largest portion of the di- encephalon, located above the hypothala- mus; contains nuclei that project informa- tion to specific regions of the cerebral cortex and receive information from it.
71
lateral geniculate nucleus
A group of cell bodies within the lateral geniculate body of the thalamus that receives fibers from the retina and projects fibers to the primary visual cortex.
72
medial geniculate nucleus
A group of cell bodies within the medial geniculate body of the thalamus; receives fibers from the auditory system and projects fibers to the primary auditory cortex.
73
ventrolateral nucleus
A nucleus of the thalamus that receives input from the cer- ebellum and sends axons to the primary motor cortex.
74
hypothalamus
he group of nuclei of the diencephalon situated beneath the thalamus; involved in regulation of the au- tonomic nervous system, control of the an- terior and posterior pituitary glands, and integration of species-typical behaviors.
75
optic chiasm
An X-shaped connection between the optic nerves, located below the base of the brain, just anterior to the pituitary gland.
76
anterior pituitary gland
The anterior part of the pituitary gland; an endocrine gland whose secretions are controlled by the hypothalamic hormones.
77
neurosecretory cell
A neuron that secretes a hormone or hormonelike substance.
78
posterior pituitary gland
The posterior part of the pituitary gland; an endocrine gland that contains hormone-secreting terminal buttons of axons whose cell bodies lie within the hypothalamus. (oxytocin and vasopressin)
79
tectum
The dorsal part of the midbrain; includes the superior and inferior colliculi.
80
superior colliculi
Protrusions on top of the midbrain; part of the visual system.
81
inferior colliculi
Protrusions on top of the midbrain; part of the auditory system.
82
tegmentum
The ventral part of the mid- brain; includes the periaqueductal gray matter, reticular formation, red nucleus, and substantia nigra.
83
reticular formation
A large network of neural tissue located in the central region of the brain stem, from the medulla to the diencephalon.
Receives sensory information by means of various pathways and projects axons to the cerebral cortex, thalamus, and spinal cord. It plays a role in sleep and arousal, attention, muscle tone, movement, and various vital reflexes.
84
periaqueductal gray matter
The region of the midbrain surrounding the cerebral aqueduct; contains neural circuits involved in species-typical behaviors.
85
red nucleus
A large nucleus of the midbrain that receives input from the cerebellum and motor cortex and sends axons to motor neurons in the spinal cord.
86
substantia nigra
A darkly stained re- gion of the tegmentum that contains neurons that communicate with the caudate nucleus and putamen in the basal ganglia.
87
hindbrain
The most caudal of the three major divisions of the brain; includes the metencephalon and myelencephalon.
88
cerebellum
A major part of the brain located dorsal to the pons, containing the two cerebellar hemispheres, covered with the cerebellar cortex; an important component of the motor system.
89
cerebellar cortex
The cortex that covers the surface of the cerebellum.
90
deep cerebellar nuclei
Nuclei located within the cerebellar hemispheres; receive projections from the cerebellar cortex and send projections out of the cerebellum to other parts of the brain.
91
pons
The region of the metencephalon rostral to the medulla, caudal to the mid- brain, and ventral to the cerebellum. Important for sleep and arousal.
92
medulla oblongata
The most caudal portion of the brain; located in the myelencephalon, immediately rostral to the spinal cord.
- Part of the reticular formation, including nuclei that control vital functions such as regulation of the cardiovascular system, respiration, and skeletal muscle tone.
93
spinal root
A bundle of axons surround- ed by connective tissue that occurs in pairs, which fuse and form a spinal nerve.
94
cauda equina
A bundle of spinal roots located caudal to the end of the spinal cord.
95
caudal block
The anesthesia and paraly- sis of the lower part of the body produced by injection of a local anesthetic into the cerebrospinal fluid surrounding the cauda equina.
96
dorsal root
The spinal root that contains incoming (afferent) sensory fibers.
97
ventral root
The spinal root that contains outgoing (efferent) motor fibers.
98
where are white and gray matter in the spinal cord?
white matter is on the outside and gray matter is on the inside
99
cranial nerves
A peripheral nerve attached directly to the brain.
100
vagus nerve
The largest of the 12 cranial nerves, conveying efferent fibers of the parasympathetic division of the autonomic nervous system to organs of the thoracic and abdominal cavities. (nerve 10)
101
olfactory bulb
The protrusion at the end of the olfactory nerve; receives input from the olfactory receptors.
102
spinal nerve
A peripheral nerve attached to the spinal cord.
103
afferent axon
An axon directed toward the central nervous system, conveying sensory information.
104
dorsal root ganglion
A nodule on a dorsal root that contains cell bodies of afferent spinal nerve neurons.
105
efferent axon
An axon directed away from the central nervous system, conveying motor commands to muscles and glands.
106
somatic nervous system
The part of the peripheral nervous system that con- trols the movement of skeletal muscles or transmits somatosensory information to the central nervous system.
107
autonomic nervous system (ANS)
The portion of the peripheral nervous system that controls the body’s vegetative functions.
108
sympathetic division
The portion of the autonomic nervous system that controls functions that accompany arousal and expenditure of energy.
109
sympathetic ganglia
Nodules that contain synapses between preganglionic and postganglionic neurons of the sympathetic nervous system.
110
sympathetic ganglion chain
One of a pair of groups of sympathetic ganglia that lie ventrolateral to the vertebral column.
111
preganglionic neuron
The efferent neuron of the autonomic nervous system whose cell body is located in a cranial nerve nucleus or in the intermediate horn of the spinal gray matter and whose terminal buttons synapse upon postganglionic neurons in the autonomic ganglia.
112
postganglionic neuron
Neurons of the autonomic nervous system that form synapses directly with their target organ.
113
parasympathetic division
The portion of the autonomic nervous system that controls functions that occur during a relaxed state.
