Chapter 7: The Structure of the Nervous System Flashcards
1
Q
What does brain organization follow?
A
The mammalian plan
2
Q
What are the nervous system divisions?
A
Cerntral Nervous System (CNS) and Peripheral Nervous System (PNS)
3
Q
Ipsilateral v. Contralateral
A
Ipsilateral is same side, while contralateral is opposite sides
4
Q
What are the anatomical plans of section?
A
Midsagittal, horizontal, coronal
5
Q
What is the CNS encased in?
A
Bone
6
Q
What is the cerebrum?
A
-Largest part of the brain
-2 Hemispheres
-Sensations and movement
-Right side controls left side of body
-Left side controls right side of body
7
Q
What is cerebellum?
A
-Latin for “little brain”
-Same number of neurons as cerebrum
-Movement control center
-Right side controls the right side of the body
8
Q
Brain Stem
A
-Relay nerve fibers
-Vital functions-breathing, consciousness, body temp,
-Damage is usually fatal
9
Q
Spinal Cord
A
-Attached to the brain stem
-Major conduit of information from skin, joints, muscles to brain and vice versa
10
Q
How does the spinal cord communicate?
A
Via spinal nerves (PNS)
11
Q
Dorsal root
A
Sensory info. to the spinal cord
12
Q
Ventral Root
A
Motor info. from the spinal cord
13
Q
Somatic PNS
A
Under voluntary control, innervates skin, joints, muscles
14
Q
Somatic Motor Axons
A
Innervate muscle (NMJ)
15
Q
Somatic Sensory Axons
A
Dorsal root ganglia
16
Q
Dorsal root ganglia
A
Clusters of neuronal cell bodies outside the spinal cord
17
Q
Visceral PNS/Autonomic nervous system
A
-Involuntary vegetative
-Innervates internal organs, blood vessels, glands
-Non-voluntary emotional reactions like butterflies in stomach/blushing
18
Q
Visceral Sensory
A
Blood pressure, oxygen content in blood
19
Q
Visceral motor: contraction/relaxation of:
A
-Smooth muscle in walls of intestines and blood vessels
-Cardiac muscle
-Secretory function in glands
20
Q
Afferent
A
(“Carry to”) Carry information toward a particular point
21
Q
Efferent
A
(“Carry from”) Carry information away from a point
22
Q
The Cranial Nerves
A
-12 nerves from brain stem (Numbered anterior to posterior
-Mostly innervate the head
-Some are axons from CNS, somatic PNS, or visceral PNS
23
Q
Meninges
A
-Greek for “covering”
-3 membranes that surround the CNS
24
Q
Dura Mater
A
-Latin for “hard mother”—leather-like consistency
-Tough, inelastic bag
25
Arachnoid Membrane
-Greek for “spider”
-Subdural hemtoma (bleed) in the subdural space compresses brain and disrupts function (drill/drain)
26
Pia Mater
-Latin for “gentle mother”
-Thin membrane that adheres to the brain’s surface
-Blood vessels that innervate the brain
-Seperated from arachnoid by fluid-filled space=subarachnoid space
27
Ventricles
Cerebrospinal fluid (CSF)-filled caverns and canals inside brain
28
Choroid Plexus
Specialized tissue in ventricles that secretes CSF
29
How does CSF moves through the ventricles?
It circulates through the ventricles and exits into aubarachnoid space through apertures (small openings) and is absorbed by the blood vessels: arachnoid villi
30
Hydrocephalus
-“Water on the brain”
-Flow of CSF is impaired so ventricles swell and compress CNS
31
What is the treatment of hydrocephalus?
Inserting a tube into the ventricle to drain off excess fluid into peritoneal cavity
32
The direction closest to the rat’s nose traveling from the tail up through the spinal column is called
Rostral
33
What part of your brain functions as the movement control center?
Cerebellum
34
Which part of the nervous system is responsible for the feeling of butterflies in your stomach?
Autonomic NS
35
Which of the meninges derives its name from the Latin phrase for hard mother?
Dura mater
36
What term means water on the brain?
Hydrocephalus
37
Which technique measures activity in the brain by comparing the oxygenation levels of hemoglobin?
fMRI
38
From which part of the neural tube does the nervous system originate?
Ectoderm
39
The hindbrain is also called the
Rhombencephalon
40
What is the axonal bridge that links the 2 cerebral hemispheres?
Corpus Callosum
41
Bumps on the surface of the cerebral cortex are called
Gyri
42
Describe the CLARITY method and why it’s used
-It renders tissue optically clear
-Replaces light-absorbing lipids w/ water soluble gel
-Used for seeing flourescently-labeled cells
43
CT
-Generates image of brain slice
-X-ray beams used to generate data for digitally reconstructed image
44
MRI
-Hydrogen atoms respond in the brain to perturbations of a strong magnetic field
-More detail, doesn’t need X-irradation
-Brain slice image in any plane
45
Diffusion Tensor Imaging
-Visualizes large bundles of axons
-Compares position of hydrogen atoms in water molecules over time
-Water diffuses more readily alongside axons than across them
46
Positron Emission Tomography (PET)
-Radioactive solution in blood stream emits positrons
-Measures metabolic brain activity
-Disadvantages: Spatial resolution is 5-10 nm, radiation exposure, 1 scan may take several minutes
47
fMRI
-Detects increased neuronal activity by measuring the ratio of oxyhemaglobin to deoxyhemoglobin
-More activity means more donated oxygen
-Advantages over PET: Rapid scans (50 msec), Good spatial resolution, noninvasive, no radiation
48
What does the CNS form from?
The walls of a fluid-filled neural tube
49
Endoderm
Lining of many internal organs
50
Mesoderm
Bones and muscles
51
Ectoderm
Nervous system and skin
—>Neural plate: nervous system
52
Neurulation
Neural plate becomes the neural tube
53
Neural groove forms:
Groove in the neural plate, runs from rostral to caudal
54
What forms from the walls of the groove?
Neural folds, which fuse to form the neural tube
55
What does the neural tube form?
The entire CNS
56
Neural crest
Some of neural ectoderm is pinched off and lies just lateral to the neural tube
57
Somites
-Mesoderm forms bulges on either side of the neural tube
-Forms spinal vertebrae, skeletal muscle
58
Somatic Motor Nerve
Nerves innervating the skeletal muscles
59
Anencephaly
-Anterior failure to close
-Degeneration of forebrain and skull
-Fatal
60
Spina Bifida
-Posterior failure to close
-Most severe: Posterior spinal cord may fail to form
-Less severe: Defects in meninges/vertebrae
-Requires extensive and costly medical care
61
How can you prevent a large number of neural tube defects?
Vitamin folic acid
62
What are the 3 primary vesicles of the neural tube?
Prosencephalon, mesencephalon, rhombencephalon
63
Prosencephalon
-Pro is Greek for before, encephalon for brain
-Forebrain
64
Mesencephalon
-Midbrain
65
Rhombencephalon
-Hindbrain
-Connects to caudal neural tube, which forms the spinal cord
66
Differentiation
Process by which structures become complex and specialized
67
Optic Vesicles
-Grow and invaginate to form the optic cups (retina) and optic stalk (optic nerve)
—>Retina and optic nerve are part of CNS
68
What is produced from the telencephalic vesicles?
Telencephalon (end brain)
69
Diencephalon
“between brain”, is in the middle
70
Telencephalon
Cerebral hemispheres, olfactory bulbs, basal telencephalon
71
How do telencephalic vesicles grow?
Posteriorly, over and lateral to the diencephalon
72
Where do olfactory bulbs sprout off of?
The Ventral surface
73
Diencephalon
Thalamus and hypothalamus
74
Cortical white matter
Axons to/from cerebral cortex
75
Corpus callosum
Axonal bridge b/t cerebral hemispheres
76
Internal capsule
Links the cortex w/ the brainstem/thalamus
77
Cerebral Cortex
-Analyze sensory input and command motor output
-Conscious awareness, cognition, perceptions
-Info. from the senses gets sent to the cortex
78
Thalamus
-Gateway to the cortex
-Vision, audition, somatic sensation synapse in thalamus before cortex
79
Voluntary movement
-Corticospinal tract
-Basal ganglia
80
Corticospinal Tract
Axons form cortex directly to spinal cord
81
What do axons from thalamus to cortex, or cortex to thalamus pass through?
The internal capsule
82
How do axons carry information?
Contralateral side of the body
83
How does hypothalamus control visceral nervous system?
-Fight/flight response
-Controls ANS: HR, BP
-Controls body temp.
-Motivates animals to find food/drink/sex in response to needs
-Directs pituitary to release hormones
84
Amygdala
-Fear conditioning
-Memory
-Emotional responses
85
What does the dorsal surface become?
Tectum
86
Superior colliculus/optic tectum
-Direct input from eye
-Controls eye movements
-Cranial nerves III and IV
87
Inferior Colliculus
Direct input from ear, sends to thalamus
88
Cerebral Aqueduct
-Contains CSF
-Connects rostrally w/ the 3rd ventricle
89
Corticospinal Tract
-Info. conduit from spinal cord to forebrain and vice versa, sensory systems, control of movements
-Damage causes impairment on contralateral side
90
What does the floor of the midbrain become?
Tegementum
91
Substantia Nigra
-Black substance; neuromelanin in dopaminergic neurons
-Control of voluntary movement
92
Red Nucleus
-Pale pink (iron)
-Control of voluntary movement
93
Mentecephalon
Rostral
94
Cerebellum
-Movement control center —> coordination
-Inputs from spinal cord and pons (goals from cortex)
95
Pons
-Latin for “bridge”
-90% of descending axons from midbrain synapse here
-Relay info to cerebellum
96
Myelencephalon
-Caudal
-Medulla oblongata
97
Is there a 4th ventricle?
Yes
98
Rostral development
Rhombic lip along dorsal-lateral wall grows dorsally and medially
—>fusion into cerebellum
99
The ventral and lateral walls swell to form?
Medulla
100
Cochlear Nuclei
-Hearing
-Axons of auditory nerves synapse here
-Send axons to inferior colliculus and others
-Damage lead to deafness
101
Touch
Somatic sensory information from spinal cord to thalamus
102
Taste
From tongue to thalamus
-Cranial nerve XII: Tongue motor neurons
103
Medullary pyramids
-White matter tracts
-Axons don’t synapse in pons
-Most from cortex (CST)
104
Pyramidal Decussation
Axons cross to the other side of the midline
105
What does the ependymal layer form?
Roof of the 4th ventricle
106
Caudal neural tube expands to form?
Spinal cord
107
Does the spinal canal contain CSF?
Yes
108
What does the cross section of the differentiation of the spinal cord look like?
Has a gray matter butterfly appearance
109
Dorsal horn
-Upper part of butterfly wings
-Recieve sensory input from dorsal root fibers
110
Ventral Horn
-Lower part of butterfly wings
-Motor neurons project axons to muscle
111
Intermediate Zone
-In b/t dorsal horn and ventral horn
-Interneurons that shape motor outputs in response to sensory inputs and descending outputs from the brain
112
What does the white matter consist of?
Dorsal columns, lateral columns, ventral columns
113
Dorsal Columns
-Somatic sensory (touch) information toward the brain
-Descussate (cross) and synpase in medulla —> right brain feels left body
114
Lateral Columns
-Descending corticospinal tract (CST;voluntary movement)
-Cross in medulla
-Innervate intermediate zone and ventral horn
115
Spinal Cord Function
-Relay information from skin, joints, muscles to brain and vice versa
-Beginning analysis of sensory information
-Coordinating movements
-Simple reflexes
116
What are the differences in rat and human brains?
Sulci and Gyri, smaller human olfactory bulb, growth of cerebral hemisphere: temporal, frontal, parietal, occipital
117
Sulci
Grooves
118
Gyri
Bumps
119
What do the sulci and gyri do for the human brain?
Increased surface area of the brain
120
Temporal lobe
Hearing
121
Frontal lobe
Executive function/memory/motor function/etc.
122
Central sulcus
Posterior border of frontal lobe
123
Parietal lobe
Sensory/language
124
Occipitial lobe
Vision
125
What are common features of the cerebral cortex in vertebrates?
1. Cell bodies in layers/sheets parallel to surface of brain
2. Surface layer separated from pia mater, layer I or molecular layer
3. Large apical dendrites from pyramidal cells form multiple branches in layer I
126
Hippocampus
-Greek for “seahorse”
-Single layer of cells, folded
-Limbic system
-Learning and memory
127
Olfactory cortex
-2 cell layers
-Continuous w/ olfactory bulb
128
Neocortex
Found only in mammals
129
What separates olfactory cortex from neocortex
Rhinal fissure
130
Area 17
Visual cortex
131
Area 4
Motor cortex
132
Smallest function unit
-Neocortical column
133
What is the conncectome of the neocortex?
Detailed wiring diagram of connections
134
Primary Sensory Areas
First to recieve signals
135
Secondary Sensory Areas
Heavy connections w/ primary areas
136
Motor Areas
Control of voluntary movement
137
What are more recent evolutions of association areas of cortex?
-The “mind”
-Interpreting behaviour in terms of unobservable mental states
138
Which is NOT common to most mammals?
Association
