Chapter 12: Central Nervous System Flashcards
1
Q
Central Nervous System
A
consists of only brain/spinal cord tissues
2
Q
Cephalic
A
relating to head or cranium
3
Q
Cephalization
A
concentration of neural/sensory organs towards body’s anterior end (cranial); highest level reached in human brain
4
Q
Brain appearance
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accumulation of wrinkled, pinkish-gray tissue
5
Q
Brain weight
A
1,450-1,600g (3.1-3.5 lbs) ~2% of total body weight
6
Q
Brain size
A
body mass determines brain size
7
Q
Brain surface anatomy
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- cerebral hemispheres (cerebrum)
- Cerebellum
- brain stem
8
Q
Neural Tube ~ 4 weeks
A
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rhombencephalon (hindbrain)
9
Q
Posterior end of neural tube
A
becomes spinal cord; exits through foramen magnum
10
Q
Prosencephalon (forebrain) secondary vesicles
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- telencephalon
2. diencephalon
11
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Mesencephalon (midbrain) secondary vesicle
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Mesencephalon
12
Q
Rhombencephalon (hindbrain) secondary vesicles
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- Metencephalon
2. Myelencephalon
13
Q
Telencephalon adult structure
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Cerebrum: cerebral hemispheres (cortex, white matter, basal nuclei)
14
Q
Diencephalon adult structure
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Diencephalon (thalamus, hypothalamus, epithalamus) retina
15
Q
Mesencephalon adult structure
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Brain stem: midbrain
16
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Metencephalon adult structure
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- Brain stem: pons
2. Cerebellum
17
Q
Myelencephalon adult structure
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Brain stem: medulla oblongata
18
Q
Midbrain/Cervical flexures
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cause cerebral hemisphere to grow posteriorly & laterally at same time (horse-shoe shaped patter)
19
Q
Basic CNS pattern
A
gray-white (internal to external)
20
Q
Spinal cord pattern
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gray-white
21
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Brain stem pattern
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gray-white
22
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Cerebrum/Cerebellum pattern
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gray-white-gray (additional outer gray matter is cortex)
23
Q
lateral ventricles
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paired C-shaped cerebral structures
24
Q
Septum pellucidum
A
a thin membrane that medially separates the lateral ventricles
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third ventricle
middle ventricle located in diencephalon
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cerebral aquaduct
connects third and fourth ventricle
27
fourth ventricle
hindbrain location being dorsal to pons
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lateral/median apertures
allow CSF to move into external spaces of brain/spinal cord
29
Cerebral hemispheres
paired superior brain structures (83% of total brain mass)
30
Gyrus
elevated ridge-like area (top of convolution)
31
Sulcus
shallow groove located between adjacent gyri
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Fissure
deep groove separating large brain areas
33
longitudinal fissure
separates L/R cerebral hemispheres
34
Transverse cerebral fissure
separates cerebrum from cerebellum
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Cortex
- superficial gray matter area w/ cognitive function
| - nerve cell bodies, nonmylenated fibers, glial cells
36
white matter of cerebrum
subcortical area, allows communication between cerebrum & other CNS structures
37
basal nuclei
- organized subcortical gray matter areas w/ roles in motor control, attention, cognition
- centers of activity lying deep within cerebral white matter
38
central sulcus
separates frontal/parietal lobes
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precentral/postcentral gyri
border central sulcus
40
parieto-occipital sulcus
separates parietal/occipital lobes
41
lateral sulcus
separates temporal from parietal/frontal lobes
42
Insula
internal brain lobe, located deep to lateral sulcus
43
Frontal lobe
higher brain functions (good vs. bad actions)
44
Parietal lobe
integrates sensory information (smell & taste)
45
Temporal lobe
auditory processing/long-term memory
46
Occipital lobe
visual processing (color discrimination)
47
Insula
emotion, homeostasis regulation, gustation (taste)
48
Cerebral cortex location
- superficial to cortical white matter
| - 40% brain mass
49
Cerebral cortex structure
- 6 layers of gray matter including cell bodies, dendrites, glial cells, blood vessels
- all neurons are interneurons
50
Cerebral cortex function
- area of conscious mind (self-awareness), non-emotional cognitive brain area
- enables memory, perception, reasoning, judgement, sensation, also communication, voluntary movements
51
Primary motor cortex
- conscious control of skilled/precise motor movements, located in pre-central gyrus
- houses long pyramidal cell tracts extending to spinal cord
52
Premotor cortex
helps plan complex (skilled) movements
53
Broca's area
controls speech production (muscles)
54
frontal eye field
controls voluntary eye movements
55
Primary somatosensory cortex
receives input from skin, skeletal, joint receptors (spatial discrimination area)
56
gustatory/visual/auditory/vestibular cortexes
special senses input regions
57
visceral sensory area
conscious perception of visceral condition (indigestion, full stomach)
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Wernicke's area
involved in language development/speech comprehension
59
Multimodal association areas
integrates information from several sensory origins/sends output to many motor areas
60
anterior association areas
processes high-level, complex information (intellect, learning, recall, personality, judgement)
61
posterior association areas
pattern/face recognition
62
limbic association areas
stores emotional impact of important events
63
lateralization
hemispheres are not always equal in function, one side specializes in a particular task ("handles it")
64
left hemisphere
greater language abilities, math, logic skills
65
right hemisphere
greater visual-spatial, emotion, artistic skills
66
contralateral function
sensory & motor functions are controlled by opposite cerebral hemispheres
67
cerebral dominance
tendency of one hemisphere to exercise more control over certain functions like language & handedness
68
cerebral white matter
deep to cortical gray matter, contains several fiber tracts (bundles) allowing upper/lower CNS communication
69
association fibers
connects different areas of same hemispheres
70
commissural fibers
connect same area of different hemispheres, allows them to communicate and act as a whole
71
corpus callosum
wide, flat budle of commissural fibers
72
projection fibers
- long sensory/motor fibers uniting cortex w/ lower brain/spinal cord
- terminate in cerebral cortex, fans out as corona radiata fibers
73
Cerebral Basal Nuclei
- organized groups of subcortical gray matter located deep inside white matter of each cerebral hemisphere
- caudate nucleus, putamen, globus pallidus
74
Cerebral basal nuclei fuctions
- receives input from cerebral cortex & other nuclei
- filers out incorrect/inappropriate responses
- starts, stops, monitors movement intensity
75
Diencephalon
- central forebrain core surrounded by cerebrum
| - collectively encloses 3rd ventricle
76
Diencephalon composed of:
three paired gray matter structures:
1. thalamus
2. hypothalamus
3. epithalamus
77
Thalamus location
deep, hidden brain region, 80% diencephalon
78
Thalamus structure
paired, egg-shaped masses of gray matter nuclei groups, communicates directly w/ cerebral cortex
79
Thalamus function
1. receives all afferent (sensory) impulses
2. relates info to cerebral cortex (sorts/edits info w/ similar function sending to cerebral cortex as group)
3. mediates sensation, motor activities, cortical arousal, learning, memory
80
Hypothalamus location
directly inferior to thalamus
81
Hypothalamus structure
- composed of several small nuclei of varying function
| - includes mammillary bodes, infundibulum (pituitary stalk)
82
Hypothalamus functions
1. MAIN body visceral (autonomic) control center
2. regulates bp, heartbeat rate/force, digestive tract motility, breathing rate/depth, other visceral activities
3. emotional response center, body temperature regulation, food intake, water balance/thirst, sleep/wake cycles
83
Epithalamus location
most dorsal part of diencephalon, situated above/behind thalamus
84
Epithalamus structure
contains pineal gland
85
Epithalamus function
- pineal glad produces melatonin, a hormone involved in sleep regulation, sleep-wake cycles, mood
- pineal gland interacts with hypothalamus
86
Brain stem regions
1. midbrain
2. pons
3. medulla oblongata
87
Brain stem characteristics
- 2.5% of brain mass
- similar pattern to spinal cord, but w/ embedded nuclei
- controls autonomic behaviors necessary for survival
- pathway for fiber tracts between lower/higher brain centers
- embedded nuclei are associated w/ 10 of 12 cranial nerve pairs
88
Midbrain location
lies between diencephalon and pons
89
Cerebral penduncles (midbrain)
two bulging ventral structures involved in limb movement (motor), superior tracts connect to cerebellum
90
Crus cerebri (midbrain)
descending pyramidal motor (corticospinal) tract
91
Cerebral aquaduct (midbrain)
hollow tube connecting 3rd/4th ventricles
92
Nuclei (midbrain)
- corpora quadrigemina (2 superior + 2 inferior colliculi), red nucleus, substantia nigra
- motor coordination, reward, addiction limb/eye movement, reflexes
93
Pons Location
- bulges ventrally, lies between midbrain and medulla oblongata
- mostly conduction tracts running in two directions
94
Pons structure/functions
- deep projection fibers of pyramidal tract unite higher brain centers w/ spinal cord
- superficial ventral fibers from pontine nuclei coordinate motor activity between 1. pons and cerebellum, 2. cerebral motor cortex and cerebellum
- origin of 3 cranial nerves
95
Medulla Oblongata location
most inferior part of brain stem, transitions to spinal cord
96
Medulla Oblongata structure/function
- 4th ventricle location, choroid plexus situated on dorsal wall
- decussation of pyramids
- olives: oval swellings, sends sensory info to cerebellum
- contains visceral motor control areas (cardiovascular/respiratory)
97
Cerebellum location
dorsal to pons and medulla, 11% brain mass
98
vermis (cerebellum)
medial worm-like structure connecting hemispheres
99
hemispheres (cerebellum)
two bilaterally symmetrical structures separated into 3 lobes (anterior, posterior, flocculonular) by deep fissures
100
folia (cerebellum)
transversely oriented pleat-like gyri of gray matter cortex
101
arbor vitae (cerebellum)
tree-like patter of central white matter
102
Purkinje cells (cerebellum)
large cortical neurons w/ many dendritic branches, major role in controlling motor movement
103
cerebellar punducles
connects cerebellum to brain stem
104
Cerebellum functions
1. provides precise timing/correct muscle contraction pattern
2. plays role in cognition (word assocation, puzzle solving)
3. ensures proper balance/posture
* All activities occur subconsciously
105
Limbic system
- situated around thalamus
- composed of amygdala, fornix, cingulate gyrus
- controls emotional response, memory formation
106
Reticular formation
- located in brain stem
- made up of raphe nuclei, medial nuclei group, lateral nuclei group
- involved in regulating cerebral cortex sensory input, cortical arousal, control of motor behavior
107
Brain protection mechanisms
1. bone-prevent/reduce traumatic injury
2. meninges-connective tissue membrane barriers
3. cerebrospinal fluid-support
4. blood-brain barrier-cellular/metabolic barrier altering brain capillary permeability
108
Meninges location
lie between skull & cerebral gray matter
109
meninges structure
- 3 successive connective tissue membranes lying external to both brain/spinal cord
- dura, arachnoid, pia maters
110
meninges functions
1. cover/protect CNS
2. protect blood vessels/enclose venous sinuses
3. contain CSF
forms partitions within skull
111
Dura mater
-outer menix tough fibrous connective tissue
112
periosteal dura
oriented outward towards skull bone
113
meningeal dura
oriented inward towards arachnoid mater
114
Dural venous sinuses
venous blood channels created by a separation of dural/periosteal/meningeal layers
115
superior sagittal sinus (dura mater)
open venous blood collection area, returns blood to internal jugular veins
116
Subdural space
narrow space between dura mater & arachnoid membrane (site of subdural hematoma)
117
dural septa
protective dura mater membranes extending inward to separate cerebral hemispheres/cerebellar lobes
118
falx cerebri (dural septa)
dips into longitudinal fissure
119
tentorium cerebelli (dural septa)
extends into cerebellar transverse fissure
120
falx cerebelli (dural septa)
runs along cerebellum vermis (midline)
121
Arachnoid mater
middle menix composed of loose connective tissue
122
subarachnoid space
- wide area beneath arachnoid mater and above pia mater filled with CSF
- follows contours of gyri/fissures but doesnt extend into sulci
- spider-like connective tissue filaments are embedded in underlying pia mater, blood vessels weave through this space
123
arachnoid villi
- finger-like projections of arachnoid mater protruding into dural venous sinuses
- returns CSF to venous blood
124
Pia Mater
- inner meninx made of thin, translucent connective tissue
- surrounds brain/spinal cord
- follows every brain contour
125
Pia Mater (2)
- highly vascular membrane (rich in blood supply)
- smaller blood arterioles/capillaries pass through pia mater to nourish brain
- nutrients move from blood to brain extracelluar fluid
