chap 12 CNS Flashcards
where does CNS develop from
from embryonic neural tube
what does the neural tube become
the brain and spinal cord
what do neural crest cells give rise to
sensory and autonomic neurons of the PNS
what does the opening of the neural tube become
the ventricles
what are the ventricles
four chambers within the brain
filled with CSF
continous with each other and with the central canal of the spinal cord
anatomy of the brain
cerebral hemispheres (cerebrum)
diencephalon
brain stem
cerebellum
what is the largest portion of the brain
cerebrum
how much does the cerebrum weigh
1200 g - females
1400g - males
what is the surface of the cerebrum made of
gyri
sulci
what is gyri
ridges
what are sulci
grooves
surface gyri and sulci of cerebrum
central sulcus
precentral gyrus
postcentral gyrus
what are fissures
deep grooves that divide the cerebrum into different regions of the brain
major fissure of cerebrum
longitudinal fissure
surface lobes of the cerebrum
frontal lobe
temporal lobe
parietal lobe
occipital lobe
actions of frontal lobe
voluntary motor function motivation agression smell mood
actions of temporal lobe
olfactory and auditory input
memory
abstract thought
judgement
actions of parietal lobe
integration of sensory information except smell, hearing, and vision
actions of occipital lobe
vision and integration of visual input
integration
reception and evaluation of information
specialized areas of the cerebrum
frontal lobe, motor cortex
other lobes, sensory cortex
actions of motor cortex
voluntary skilled muscle movements
actions of sensory cortex
sensory interpretation and association
layers of the cerebrum
cerebral cortex
cerebral medulla
basal nuclei
describe cerebral cortex
gray matter 1/8 thick composed of neuron cell bodies highly convoluted involved in higher brain functions and motor
why is the cerebral cortex gray
made up of cell body, no myelin
what are the higher brain functions
speech memory logic emotion interpretation of sensory input consciousness
describe cerebral medulla
myelinated nerve tracts inside the gray matter that connect areas of the CNS
example of cerebral medulla
corpus callosum
what is the corpus callosum
connector between hemispheres
why is the cerebral medulla white
white matter because there is more myelin
describe basal nuclei
internal islands of gray matter dispersed bilaterally in the inferior cerebrum, diencephalon, and midbrain
what do basal nuclei do
important in controlling and modifying motor functions; especially in start & stop movements
what clinical diseases affect the basal nuclei
parkinson’s disease
huntington’s disease
what is parkinson’s disease
slow tremors
cells that make dopamine are destroyed and dopamine is NT for muscle function
treatment for parkinson’s disease
L-dopa
what is huntington’s disease
rapid jerky movements
genetic
degeneration of basal nuclei and cerebral cortex
treatment for huntington’s disease
block NTs
describe diencephalon
sits on top of the brain stem
enclosed by the cerebral hemispheres
the three parts that make up the diencephalon
thalamus
hypothalamus
epithalamus
describe thalamus
surrounds 3rd ventricle
relay station to cerebral cortex for sensory impulses
describe hypothalamus
under the thalamus
important ANS center
important part of limbic system
what does hypothalamus regulate
body temp hunger thirst satiety swallowing emotions
what is attached to the hypothalamus
the pituitary gland
how do the pituitary gland and the hypothalamus work together
the hypothalamus indirectly influences many body functions by sending signals through the pituitary gland to regulate its secretion of hormones
what kind of tissue is the pituitary gland
endocrine
what body functions are regulated from the hormones
metabolism
reproduction
responses to stressful stimuli
urine production
describe the epithalamus
forms the roof of the 3rd ventricle
houses the pineal body
includes choroid plexus
define plexus
group of blood vessels
what does pineal body do
melatonin production (sleep/wake cycle) mood
what does choroid plexus do
forms CSF
describe the brain stem
attaches to the spinal cord
integrates many vital functions
what happens if there is minor damage to the brain stem and why
can cause death
higher integration areas like the cerebellum can withstand more damage
parts of the brain stem
midbrain
pons
medulla oblongata
describe midbrain
composed mostly of tracts of nerve fibers
describe pons
they include nuclei involved in the control of breathing
describe medulla oblongata
most inferior part of the brain stem
merges into the spinal cord
includes important ascending and descending nerve tracts
what does the medulla oblongata control
autonomic control center for heart rate blood pressure breathing swallowing vomiting
describe cerebellum
two hemispheres with convoluted surfaces
what does cerebellum do
provides involuntary coordination of body movements
plays a role in posture and equilibrium
ways that CNS is protected
scalp and skin skull and vertebral column meninges CSF blood brain barrier blood supply to the brain
what are meninges
membranes
types of meninges
dura mater - superficial
arachnoid mater
pia mater - deepest
2 layers of dura mater
periosteum
meningeal layer
what do the 2 layers of dura mater form
dural sinuses
describe CSF
similar to blood but no red blood cells and much lower protein level
circulated in subarachnoid space, ventricles, and central canal
clear in color
purpose of CSF
supplies nutrients
form protective cushion around CNS
removes wastes
describe ventricles
right and left lateral ventricles
composed of anterior, posterior, and inferior horns
3rd ventricle, cerebral aqueduct, and 4th ventricle
apertures
what are apertures
narrowed openings into subarachnoid space of spinal cord
purpose of dural venous sinuses
blood and CSF collection for return to circulatory vessels exiting skull
describe the blood brain barrier
tight junctions between endothelial blood vessel cells cause substances to pass through cells to become CSF
large substances can not utilize the route between cells and are barred from CSF
what kind of substances can get through blood brain barrier
lipid soluble substances through lipid-soluble transport
ex. nicotine, ethanol, heroin
how do water-soluble molecules get across blood brain barrier
move across by mediated transport
ex. amino acids and glucose
how much O2 is used by brain
20% of all oxygen consumption
can nerve cells store energy
no
they cant store glucose or energy compounds like muscle tissue
what happens if there is an interruption of blood flow to the brain
pass out or cause irreversible brain damage
drugs that can get past blood brain barrier
L-Dopa
lipid-soluble drugs
clinical applications of brain
meningitis hydrocephalus concussion contusion degenerative injuries
describe hydrocephalus
child has fontanels and can expand
a blockage of drainage of CSF
what is a concussion
disturbance of brain function
shaking
what is a contusion
bruising of brain, permanent
ex. subdural hematoma
some degenerative injuries
cerebrovascular accidents
alzheimer’s disease
describe CVA
death of brain tissue because of blood depravation
causes of CVA
hemorrhagic
ischemic
what is the glutamate cascade
during a stroke, oxygen deprived presynaptic neurons release large amounts of glutamate
glutamate binds to postsynaptic neurons and stimulates them to release nitric oxide (NO)
NO diffuses from postsynaptic cells and causes damage to surrounding cells
describe alzheimer’s disease
progressive degenerative brain disease
characterized by abnormal protein deposits and twisted fibers within neurons
symptons of alzheimer’s disease
memory loss irritability confusion hallucinations death
describe spinal cord
nerve pathways to & from the brain
extends from medulla oblongata to the region of T12
what is it called below T12
cauda equine
anatomy of spinal cord
internal butterfly shaped gray matter exterior white matter central canal filled with CSF anterior median fissure cushioned and protected by meninges
gray matter of spinal cord
horns
interneurons
types of horns
dorsal horns
ventral horns
lateral horns
exterior white matter
ascending & descending myelinated nerve tracts
posterior, anterior, and lateral columns (funiculus)
the meninges that protect the spinal cord
dura mater
arachnoid mater
pia mater
spinal cord dura mater
separated from the periosteum by the epidural space
epidural space
fat
blood vessels
where is anesthesia given for child birth
epidural space
what is the subdural space
between the dura and arachnoid mater
can fill with blood as a result of trauma and exert pressure on the brain (subdural hematoma)
what is the subarachnoid space
between the arachnoid mater and pia mater
filled with CSF
below L2 injections and spinal tap
spinal tap
fluid drawn out for lab exam
pia mater
innermost delicate membrane attached directly to the spinal cord
spinal nerves
dorsal root
ventral root
dorsal root
sensory neurons
cell bodies from dorsal root ganglia (outside of cord)
ventral root
motor neurons
cell bodies in ventral horn of gray matter
flaccid paralysis
complete
damage to ventral motor roots or anterior horn
no muscle tone maintained (atrophy)
spastic paralysis
jerky uncontrolled movements
damage to cerebral cortex but spinal reflexes remain intact
paraplegic
both lower limbs affected
damage to spinal cord at level of T1-L2
