A and P chapter 14 Brain and cranial nerves Flashcards
(273 cards)
1
Q
how much of the brain does the cerebrum constitute
A
83%
2
Q
where are 50% of the brains neurons located
A
cerebellum
3
Q
which parts of the brain are gray matter
A
cerebral cortex
basal nuclei
4
Q
what makes up the white matter
A
bundles of axons and myelin
5
Q
what are the 3 layers of embryonic tissue
A
endoderm
mesoderm
ectoderm
6
Q
what does the ectoderm germ layer give rise to
A
nervous tissue
7
Q
what are the brains protection
A
bone
meninges
cerebrospinal fluid
blood-brain barrier
8
Q
what are the 3 meninges of the brain
A
dura mater
arachnoid mater
pia mater
9
Q
describe the dura mater
A
double layer fused together except in spaces where it makes the dural sinuses
10
Q
what are the dural sinuses for
A
collect venous blood from brain and direct it to the internal jugular veins
11
Q
what is the dural septa
A
part of the dura mater that creates cranial cavity partitions
12
Q
name the types of dural septa and describe them
A
dural septa part of dura mater
falx cerebri–> in longitudinal fissure; seperates 2 cerebrum
falx cerebelli–> on vermis of cerebellum; seperates halves of cerebelli
tentorium cerebelli–> in transverse fissure; separates cerebellum and cerebrum
13
Q
describe the arachnoid mater
A
loose brain covering that does not dip into sulci/fissures
14
Q
what is the subdural space
A
serous cavity that separates arachnoid and dura mater
15
Q
what is the subarachnoid space
A
separates arachnoid and pia mater
16
Q
what are arachnoid villi
A
a valve-like structure that protrudes through the dura mater into the sagittal sinus where CSF is absorbed into venous blood of the sinus
17
Q
describe the pia mater
A
delicate layer with lots of tiny blood vessels
clings tightly to brain and does dip into all the grooves
where concussions happen
18
Q
what are ventricles
A
spaces that make CSF in the brain
19
Q
name the ventricles
A
R and L ventricles
3rd
4th
20
Q
what ventricle connects to the cerebral aqueduct superiorly
A
3rd ventricle
21
Q
what ventricle connects to the central canal that CSF flows down to the spinal cord
A
4th
22
Q
what is the purpose of CSF
A
liquid cushion
floats brain in skull
nourishes brian and takes away waste
23
Q
whats in CSF
A
sodium and chloride
potassium
calcium
glucose
protein
24
Q
what is the purpose of the blood brain barrier
A
brain needs a constant environment to function (less variation in hormones and ions etc)
25
what easily passes through the blood brain barrier
water, glucose, amino acids, and some electrolytes
use facillitated diffusion to pass barrier
cant prevent anything lipid soluble from passing (fats, fatty acids, oxygen and carbon dioxide)
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what can pass through blood brain barrier but takes work
sodium, potassium, chloride, urea, and creatinine, metabolic waste, proteins, and some drugs/toxins
27
blood brain barrier does not include
the hypothalamus
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what is the downside to the blood brain barrier
some antibiotics and cancer meds cant pass through
29
where is the midbrain located
in between diencephalon and pons
30
where is the cerebral aqueduct located
runs through the center of midbrain and is surrounded by gray matter called the periaqueductal gray matter
31
what is the periaqueductal gray matter for
pain suppression
is an autonomic nervous system pathway
cranial nerves III and IV (oculomotor and trochlear) run through
32
what are cerebral peduncles
2 bulges on anterior that contain corticospinal motor tracts
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what are the superior cerebellar peduncles for
connect midbrain fiber tracts to cerebellum
34
name the basal nuclei
corpora quadrigemina, substantia nigra, red nucleus
35
describe the corpora quadrigemina (basal nuclei)
largest of basal nuclei
superior colliculi--> visual reflex centers
inferior colliculi--> auditory relay, startle reflex
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describe the substantia nigra (basal nuclei)
2 nuclei
high melanin content which is precursor to dopamine
makes dopamine
degeneration leads to parkinsons
37
describe the red nuclei (basal nuceli)
rich blood supply and iron pignment inside neurons (making it red)
involved in motor coordination
38
what are the functions of the pons
helps regulate normal breathing rhythm
sleep
posture
39
what is the purpose of the medulla oblongata
autonomic reflex center for body homeostasis
cardiac control
vasomotor control
respiratory rate and control
40
what are the pyramids in the medulla oblongata and what is decussation of them
two longitudinal ridges made by corticospinal fiber tracts
decussation of pyramids= crossing of the fibers from R to L or L to R
41
describe the reticular formation
loose web of gray matter that runs vertically through all levels of the brainstem
occupies space between white fiber tracts and brainstem nuclei
42
what is the purpose of the reticular formation
helps govern all somatic motor control
cardiovascular control
pain modulation
sleep/wake
habituation (ignore repetitive, inconsequential stimuli)
43
what are the two hemis seperated by in the cerebellum
vermis
44
what is the white matter in the cerebellum called
arbor vitae
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what do cerebellar peduncles do
connect brainstem and cerebellum
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what does the superior cerebellar peduncle do (midbrain)
connects to cerebral motor cortex via thalamic relays
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what does the middle cerebellar peduncle do (pons)
one way communication from pons to cerebellum
48
what does the cerebellar peduncle do (medulla)
sensory info
muscle proprioception
balance
49
what are the functions of the cerebellum
sensory, linguistic, emotional function
non motor functionalities
planning, scheduling, emotional control
50
what brain structure encloses the 3rd ventricle
diencephalon
51
describe the thalamus structure
2 lobes connected by interthalamic adhesion
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function of the thalamus
sorts out info and edits it and then sends it to other parts of brain to be executed
gateway to brain
role in motot control by signal replay betweeen cerebrum adn cerebellum
is a part of the limbic system= memory and emotional function
53
what is the function of the hypothalamus
main visceral control and body homeostasis
autonomic control center
emotional response "heart" of the limbic system
body temp reg., hunger reg., water balance, sleep/wake cycles
makes ADH and oxytocin
54
what is the infundibulum
stalk that connects with the pituitary
55
what are mamillary bodies
relay for olfactory tracts
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what controls the pituitary glands secretions
hypothalamus
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what structures in the epithalamus
pineal gland, posterior commissures, choroid plexus
58
what does the pineal gland do
makes melatonin and controls sleep and wake cycles (processes light info)
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what do the posterior commissures do
link basal nuclei and limbic system
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what does the choroid plexus do
secretes CSF
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what are the lobes of the cerebrum
frontal
parietal
occipital
temporal
insula
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describe location and function of the frontal lobe
rostral to central sulcus
voluntary motor functions, motivation, planning, memory, moodm emotion, social judgement, aggression
63
describe location and function of the parietal lobes
between central sulcus and parieto-occipital sulcus
integrates general senses, taste, and some visual info
64
describe location and function of the occipital lobe
caudal to parieto-occipital sulcus
primary visual center of brain
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describe location and function of the temporal lobes
lateral and horizontal; below lateral sulcus
functions in hearing, smell, learning, memory, some aspects of vision and emotion
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describe location and function of the insula lobe
deep to lateral sulcus
helps understand spoken language, taste and integrating info from visceral receptors
67
what is the tissue composition of the cerebral cortex
interneurons only, neuron cell bodies, dendrites, glial cells, blood vessels-- no fiber tracts
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what percent of brain is the "conscious mind"
40% and only gray matter
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what are the 3 functional areas of the cerebral cortex
motor-->voluntary functions
sensory-->allows conscious awareness of sensation
associational-->integrates info (makes info whole so we can give it meaning)
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what do commisural fibers in the cerebral cortex do
horizontal fiber tracts that communicate between 2 hemispheres (connect gray areas and allows them to work as a unit)
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what is the corpus callosum
a commisural fiber tract (largest of them actually)
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what are association fibers
horizontal fiber tracts that connect different parts of the same hemisphere
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what are projection fibers
vertical fiber tracts that connect cortex to nerves in body
nerves from left side of body cross in the brain stem and shoot towards the right brain and vice versa
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what is the internal capsule
in regard to projection fibers
compact band in the brain stem
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what is the corona radiata
in regard to projection fibers
superior to internal capsule, fibers radiate through white matter in fan like pattern
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no motor function happens unless what brain structure is involved
basal nuclei (though not directly connected to the motor cortex)
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what structures are in the corpus striatum (basal nuclei)
caudate nucleus
putamen
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what is the amygdala
basal nuclei
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what is the globus pallidus
basal nuclei
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what is the role of basal nuclei
complex and repetitive behaviors
practiced behaviors
modify voluntary motor activity
issue in nuceli causes too much or too little movement
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what is the function of the amygdala
primal fear and aggression
not impacted by alzheimers
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what neurotransmitters are inhibitory in the basal nuclei and associated areas
GABA and dopamine
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what neurotransmitters are excitatory and inhibitory in the basal nuclei and associated areas
ACh, norepinephrine, serotonin, and enkephalin
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what neurotransmitters are excitatory in the basal nuclei and associated areas
Glutamate
pathways provide most fo the excitatory signals within the basal nuclei
85
what is huntingtons disease
disorder of the basal nuclei, loss of GABA secreting neurons in the nuclei, loss of ACh neurons in many parts of brain
spastic paralysis (uncontrolled motor output)
dementia and paranoia in later stages
86
what do the limbic system and the reticular activating system have in common
networks of neurons that span across many different parts of the brain
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what is the limbic system do and where is it
emotional brain (bridge between conscious and subconscious brain, center for gratification, psychosomatic illness here)
forebrain
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what is the reticular activating system and where is it
an alert system
brain stem
89
what location are within the limbic system
amygdala, hippocampus, hypothalamus, thalamus
90
describe where reticular activating system is and what it does
in brainstem, loosely clustered gray matter neurons in white matter
keeps cortex alert and concious, whole brain arousal
allows us to move stimuli to the background (ignore it)
if severely injured here like twisting of brain stem=comatose
91
what does EEG mean and what does it do
electroencephalogram
records patterns of brain waves
92
what is induced paralysis where BP is lowered, ATP is restored, and damage is repaired
sleep
93
what is REM sleep
rapid eye movement sleep
semi awake state searching for daylight
restful sleep
94
what are the cognitive functions in the association areas of the cortex (parietal lobe, temporal lobe, frontal lobe)
parietal lobe--> helps perceive and attend to stimuli
temporal lobe--> helps identify stimuli
frontal lobe--> helps us think about the world, plan, and execute appropriate behaviors
95
what would damage to the parietal lobe cause in regard to cognitive function
contralateral neglect (unaware of objects on opposite side of body)
96
what would damage to the temporal lobe cause in regard to cognitive function
agnosia (inability to recognize, identify familiar objects; like cannot recognize faces)
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what would damage to the frontal lobe cause in regard to cognitive function
personality disorders and socially inappropriate behaviors
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what is amnesia
defects in declaritive memory; inability to describe past events
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what is procedural memory
example would be ability to tie ones shoes
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what is anterograde amnesia
unable to store new info
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what is retrograde amnesia
person cannot recall things known before injury
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what is skill memory
muscle memory
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what are some brain structures involved in memory
hippocampus
cerebellum
amygdala
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what do the primary functional areas in the cerebral cortex do
specifically responsible for perception and control
sensory and motor
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what do the secondary functional areas in the cerebral cortex do
interpret and modify what happens in the primary areas
motor and sensory
106
where is the primary somatosensory cortex and what does it do
postcentral gyrus of parietal lobe
receives info from somatic sensory receptors in skin and proprioceptors in skeletal muscle, joint, tendons
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where is the secondary somatosensory association cortex and what does it do
posterior to primary somatosensory cortex
integrates somatic sensory input so you can recognize/understand what you are sensing
108
where are the visual areas and what do they do
extreme posterior of occipital lobe
primary recieves info from retinas, surrounding association areas interpret the info
109
where are the auditory areas and what do they do
temporal lobe by lateral sulcus
info about pitch, rhythm, and volume (sound memories)
110
where is the olfactory cortex and what does it do
frontal lobe
smell, emotions and memory of limbic system
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where is the gustatory cortex and what does it do
insula lobe
taste
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where is the vestibular cortex and what does it do
insula
conscious awareness of balance
113
where is the visceral sensory areas and what does it do
insula
conscious perception of visceral sensation
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where is any and all motor output created as a thought and plan i
frontal lobe
115
what does the premotor cortex do
figures out the plan of movement
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what does the primary motor cortex do
conscious control of precise/skilled voluntary movements
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where is the broca's area and what does it do
mostly on left side of brain
controls muscles for moving mouth/tongue during speech
formulating/ thinking about what to say
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what is plasticity
ability of neurons to be used to do other things
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what are pyramidal cells of the precentral gyrus
upper motor neurons and their fibers point caudally
120
what is dyskinesis
movement disorders caused by lesions in the basal nuclei involving abnormal movement initation
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how does the cerebellum relate to motor control
smooths muscle coordination
learning motor skills
lesions cause ataxia: clumsy and awkward gate
122
what are multimodal association areas
every part of gray matter that isnt labeled "primary"
where info is being processed and integrated
123
what part of the brain makes us uniquely human
prefrontal cortex
interconnected with limbic system
lesion would cause major behavior changes in morality
phineas gage
124
in regards to multimodal association areas, what do the temporal, parietal, and occipital lobes do
recognize patterns and faces
125
what does the fornix do
connects limbic and 2 hemispheres
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where are the language association areas and what do they do
around lateral sulcus in left dominant hemi
language comprehension and creation of articulation of sounds
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what does the lateral prefrontal cortex do
comprehension and word analysis
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what does the antero-lateral temporal lobes do
coordinate auditory and visual aspects
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where is the brocas area and what does it do
antero-inferior to pre motor cortex on left side
special motor speech areas
moving mouth
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what does the wernickes area do and where is it located
on left side
sounding out unfamiliar words
131
what is brocas aphasia
can understand language but cant speak or even write
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what is wernickes aphasia
can speak but word salad
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how many pairs of cranial nerves
12
134
where do cranial nerves I and II originate from. where do the rest originate from
forebrain
rest in brainstem
135
which cranial nerves are strictly sensory
I olfactory
II optic
VIII vestibulocochlear
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which cranial nerves are strictly motor
III oculomotor
IV trochlear
VI abducens
XI accessory
XII hypoglossal
137
which cranial nerves do both motor and sensory
V trigeminal
VII facial
IX glossopharyngeal
X vagus
138
what is alzheimers
shortage of ACh and structural changes to brain
gyri shrink and neurons lost
beta amyloid plaques
tau protein tangles (not tangled in normal brain)
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what is a concussion
bruising of brain
short lived injury no longterm damage
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what is a contusion
brain tissue destruction
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what is a subdural or subarachnoid hemorrhage
bleeding in these spaces causes swelling and puts pressure on other brain tissues
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what is cerebral edema
swelling of brain from inflammation and water retention
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what is a stroke/CVA
blood circulation blocked and brain tissue dies
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what causes strokes
blood clots
compression of brain tissue
atherosclerosis of brain vessels
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what are the results of a stroke
paralysis on one side of body
sensory and language deficits
146
what is a TIA
transient ischemis attack
lasts 5-50 minutes
temporary numbness paralysis and impaired speech
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What do elevated delta waves in an EEG mean?
Brain death
