Flashcards in Chapter 15- Brain and Cranial Nerves Deck (69)
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brain regions
cerebrum
diencephalon
mesencephalon
cerebrum
pons
medulla oblongata
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meninges: outer layer
dura mater
-forms internal periosteum of skull
no epidura
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dura mater partitions
-falx cerebelli: separates right and left cerebellar hemispheres
-falx cerebri: separates right and left cerebral hemispheres
-tentorium cerebelli: separates lobes of cerebrum form cerebellum
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2 other layers of meninges
arachnoid mater:
-spidery
-spreads over brain but doesnt extend into gooves and depressions
Pia mater:
-inner most
-aids in nourishing brain
-attached to surface of brain
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ventricles
-spaces filled with CSF
-2 lateral ventricles
--connected by interventricular foramen to:
-3rd ventricle: connected by cerebral aqueduct to:
-4th ventricle: connected to central canal of spinal cord
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cerebrospinal fluid functions
-cushions
-transport nutrients, wastes and othe chemicals
-support the brain
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cerebrospinal fluid: formation
choroid plexus:
-lobes located in the ventricles
-consists of
--ependymal cells
--permeable capillaries
-CSF is taken from blood by ependymal cells and pooled in the ventricles
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cerebrospinal fluid: movement
-CSF moves throughout the entire CNS
-originated in ventricles
-through apertures in the 4th ventricles to subarachnoid space
-through central canal
-around subarachnoid space
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Cerebrospinal fluid: reabsorbed
in sagittal sinus
-a large venous tube within the dura mater
-extends along the midline of the cerebral hemispheres
-arachnoid extends into sinus through arachnoid granulations
-CSF goes back into the blood
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cerebrum: functions
-interpret sensory impulses
-voluntary muscular movements
-memory
-reasoning process
-intelligence and personality
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cerebral hemispheres
-2 hemispheres
-cnnected by corpus callosum
-separated by longitudinal fissure
-possess
--ridges-gyri
--grooves=sulci
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hemisphere separation
-receives sensory and generates motor information to the OPPOSITE side of the body
-communication between the hemispheres allowed for by corpus callosum
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cerebral gray mater
cell somas
-outer regions of cerebral lobes
-centralized in masses called basal nuclei
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cerebral white mater
myelinated axons
-commissural fibers
-association fibers
-projection fibers
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commissural fibers
connect corresponding gray areas on different hemispheres
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association fibers
connect different parts of same hemisphere
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projection fibers
connect cerebrum to lower brain areas
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cerebral lobes
frontal
parietal
temporal
occipital
insula
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cerebral lobes division
divided by special sulci
-central sulcus: separates the frontal lobe from the parietal lobe
-lateral sulcus: separates the parietal lobe from the tempoal
-parietal-occipital sulcus: separates the parietal lobe from the occipital
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cerebral regions: primary motor cortex
Primary motor cortex
-anterior to central sulcus in frontal lobe
-conscious control of skeletal muscles
-learned motor skills
-speech and eye movements
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cerebral regions: primary sensory cortex
-posterior to central sulcus on parietal lobe
-somatic sensory information from touch, pain, pressure
-monitor environment consciously
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other sensory cortexs
visual cortex:
-occipital lobe
-sight
-photoreceptors
auditory cortex:
-temporal lobe
-sound
olfactory cortex:
-temporal lobe
-smell
gustatory cortex:
-insula and frontal lobe
-taste
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cerebral regions: association areas
-one associated with most large motor or sensory cortexes
-somatic sensory
-somatic motor
-visual
-auditory
-recognize friend on phone (auditory), touch recognition
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cerebral regions: high order integrative regions: prefrontal cortex
-meat of brain
-abstract intellectual function
-predictions, problem solving
-emotional context and motivation
-timing and temporal relationships
-removal=pre-frontal lobotomy
-see ppt for picture of area
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cerebral regions: high order integrative regions: brocas speech center and general interpretive area
brocas:
-regulates breathing and vocalization
general interpretive area:
-interpretation of both written and verbal language
-sentence structure and word linkage
damage to either results in some sort of aphasia (speech blockage)
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hemisphere dominance
higher order integrative regions may be different between hemispheres
-categorical hemisphere
--speech, writing, and general interpretive area
-representational hemisphere
--identification of familiar objects
--touch and spatial analysis
--emotional relevance
right handed people tend to have their categorical hemisphere on left, and vice versa
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basal nuclei
-masses of gray matter deep in cerebral hemisphere
-act as relay station for motor impulses starting in cerebral cortex and passing to brain stem and spinal cord
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types of basal nuclei
-claustrum
-lentiform nucleus
-caudate nucleus
-amygdaloid nucleus
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claustrum
-focuses visual attention
-processes unconscious visual info
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lentiform nucleus
controls and adjusts muscle tone
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caudate nucleus
-massive head, slender tail
-maintains pattern and rhythm of movement
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amygdaloid nucleus
-tip of caudate tail
-part of limbic system
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diencephalon
-epithalamus
--pineal gland: produces melatonin
-posterior pituitary gland
-thalamus
-hypothalamus
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thalamus
central to the cerebrum
two major bodies:
-divided by the third ventricle
-connected by a interthalamic adhesion
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thalamus: function
part of limbic system:
-emotion, memory, learning
-conscious awareness of emotion
connect basal nuclei and cerebral cortex
-to each other
-to other parts of the CNS
sends sensory information to proper location within cerebrum
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hypothalamus; location
below the thalamus
-above and connected to the posterior pituitary gland
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hypothalamus: functions
-subconscious control of skeletal muscles
-coordinates autonomic nervous system (sympathetic and parasympathetic)
-the connection between the endocrine and nervous system
-directly produces hormones
-produces behavioral drives (emotions, hunger, thirst)
-regulates body temperature
-controls sleep patterns such as circadian rhythms
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mesencephalon
-midbrain
-connects brain stem and spinal cord with higher areas
-act as relay centers
-contain cerebral aqueduct that connects 3rd and 4th ventricles
-parts:
-cerebral peduncles
-red nucleus
-substantia nigra
-corpora quadrigemina
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cerebral peduncles
only connecting fibers and no nuclei
-motor fibers connecting the cortex to the spinal cord
-sensory fibers that synapse with the thalamus
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red nucleus
-highly vascularized (hence red color)
-connects cerebrum and cerebellum
-controls:
-posture
-reflexes
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substantia nigra
-controls and integrates the motor output of the basal nuclei
-produces dopamine (gives it a black color)
-deterioration may lead to parkinson's disease
--loss of control of voluntary motor function
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corpora quadrigemina
-superior colliculi
--recieves visual input from thalamus
-inferior colliculi
--receives auditory input from medulla
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pons
-rounded bulge on underside of brain stem
-separates midbrain from medulla
-masses of gray matter and nerve fibers
-relays impulses to and from medulla and cerebrum
-regulates depth of breathing
-rhythm of breathing, wakefullness, sleeping. comatose if damaged
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cerebellum
below cerebrum
2 hemispheres:
-separated by falx cerebelli
-connected by vermis
mainly white matter
-arbor vitae
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cerebellum: function
-integrates sensory information about the position of body parts
-coordinates muscle activities
-maintain posture
-fine tunes voluntary and involuntary movements
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medulla oblongata
-from foramen magnum to pons
-a point of connection for several cranial nerves
-oval swelling=olivary nucleus
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reflex centers of medulla oblongata
cardiovascular center
-adjusts blood flow and heart rate
respiratory rhythmicity center
-basic pace of respiratory movements
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reticular formation (medulla)
-network of nerve fibers associated with islands of gray matter
- interconnects areas with fibers in all major tracts
-regulates motor activities
--Inc activity=wakefulness
--dec activity=sleep
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limbic system
nuclei and tracts along the border of cerebrum and diencephalon
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cerebrum limbic system
-limbic lobe: deep to all other lobes
-hippocampus: nuclei within the lobe
-amydaloid body: basal nucleus
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diencephalon limbic system
-thalamus: relay center
-hypothalamus: behavioral drive center
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medulla limbic system
reticular formation
-sleep and wakefulness
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limbic system function
-establishes emotional states and related behavioral drives
-links intellectual functions of cortex to unconscious functions of lower brain
-facilitates memory storage
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cranial nerves
-12 total
-all originate from brain stem except 1st pair
-cell bodies fro sensory found in ganglia outside brain
-cell bodies for motor found in gray matter
-pass through foramina in skull
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cranial nerves general
- may look all disorganized in mammals
-are organized sequentially in fish and cephalochordates
-this is evidenced in a fetus as well
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12 cranial nerves
1. olfactory
2. optic
3. oculomotor
4. trochlear
5. trigeminal
6. abducens
7. facial
8. vestibulocochlear
9. glossopharyngeal
10. vagus
11. accessory
12. hypoglossal
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I
olfactory
-sensory (means sends signals up)
-smell
-passes through cribiform plate
-only sensation that does not go through the thalamus
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II
optic
-sensory
-vision
-pass through the optic foramina
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III
oculomotor
-motor (means sends signals down)
-move the majority of eye muscles
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IV
-motor
-smallest pair
-superior oblique muscles of eye only
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V
trigeminal
-mixed
-larges
-3 branches
--eye, tear gland and skin of ant. scalo, forehead and upper eyelid
--upper teeth, gum, lip and mucous lining of palate and skin of face
--scalp, skin of jaw, lower teeth, gum and lip; muscles of mastication
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VI
abducens
-motor
-form pons
-lateral rectus eye muscles only
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VII
facial
-mixed
-sensory: taste receptors on ant. 2/3 of tongue
-motor: to muscles of facial expression; stimulate tear and salivary glands
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VIII
vestibulocochlear
-sensory
-auditory nerve from medulla
-2 parts
--sensitive to changes in position of head
--interpreted as hearing
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IX
glossopharyngeal
-mixed
-sensory: form lining of pharynx, tonsils and post. 1/3 of tongue
-motor: to wall of pharynx to help swallowing
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X
vagus
-mixed
-from medulla to chest and abdomen
-sensory from lining of pharynx, larynx and esophagus and abdomen
-somatic motor: to muscles of larynx--> speech and swallowing
-autonomic motor: to heart, other smooth muscles and glands in visceral organs
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XI
-motor
2 branches
-cranial: from medulla to muscles of soft palate, pharynx and larynx
-spinal: sends motor fibers to trapezius and sternocleidomastoid
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XII
hypoglossal
-motor
-from medulla to tongue
-for speaking, chewing and swallowing
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