Ch. 12 Flashcards
What are the functions of the cerebrum?
-performs higher mental functions
-interprets sensory stimuli
-plans and initiates movement
What are the functions of the diencephalon?
-processes, integrates and relays information
-maintains homeostasis
-regulates biological rhythms
What are the functions of the cerebellum?
monitors and coordinates movement
What are the functions of the brainstem?
-maintains homeostasis
-controls certain reflexes
-monitors movement
-integrates and relays information
What is the highest level of the brain?
cerebrum
What is the second highest level of the brain?
diencephalon
What is the third highest level of the brain?
cerebellum
What makes portions of the brain appear white?
myelinated axons
What makes portions of the brain appear gray?
unmyelinated axons and cell bodies
How is the matter organized in the brain?
gray matter is on the surface
white matter is deep
How is the matter organized in the spinal cord?
gray matter at center surrounded by white matter pathways
When does brain development start?
as early as week 4 in fetal development
What is necessary to close neural tubes during fetal brain development?
folic acid
What does the forebrain give rise to?
telencephalon and diencephalon
What does the telencephalon give rise to?
cerebrum
What does the diencephalon give rise to?
the name stays the same!
What does the midbrain give rise to?
mesencephalon
What does the mesencephalon give rise to?
brainstem: midbrain
What does the hindbrain give rise to?
metencephalon and myelencephalon
What does the metencephalon give rise to?
brainstem: pons
cerebellum
What does the myelencephalon give rise to?
brainstem: medulla oblangata
What does the cerebrum include?
cortex and basal nuclei
What is the cortex?
surface gray matter (all of the cells on top of your head)
What are gyri?
ridges
What are sulci?
grooves
What do fissures do?
separate lobes of the brain
much deeper grooves
What is the insula in the cerebrum?
fissure that separates the frontal and parietal lobes from the temporal lobe
What does the parietal association cortex do?
brings sensory information together and helps to form imagery
What is in front of the motor cortexes?
premotor cortex
What is the premotor cortex responsible for?
intelligence
personality
association area
pull together different information
What is the primary somato-sensory cortex responsible for?
sense of touch
What is the frontal eye field?
eye motor planning area
What is the primary motor cortex responsible for?
order to move
What is the somato sensory association cortex responsible for?
brings touch info together
What are the motor areas of the brain and what do they do?
precentral gyrus of frontal lobe
directs voluntary movements
location of upper motor neurons
What are the sensory areas of the brain and what do they do?
postcentral gyrus of parietal lobe
receives somatic sensory information (touch, pressure, pain, vibration, and temperature)
What is the visual cortex?
primary cortex in the occipital lobe
information from sight receptors
What is the auditory cortex?
primary cortex in the temporal lobe
information from sound receptors
What is the olfactory cortex?
primary cortex in the limbic system
base of brain
information from odor receptors
What is the gustatory cortex?
primary cortex in the insula
information from taste receptors
What is Wernicke’s area?
general interpretative area
understanding what you see or hear
Where is the Wernicke’s area located?
only in one hemisphere
other side is general interpretative area (body language)
What is Broca’s?
speech center
responsible for producing understandable speech
What is the prefrontal cortex?
appreciation of consquences
integrates info from all sensory association areas
personality
What do the parietal and temporal association areas do?
bring info into a single picture
helps with creating imagery
What are the vestibular areas?
sensory cortex
in parietal and temporal lobes
process stimuli related to equilibrium and balance
What is the main neurotransmitter of the basal nuclei?
dopamine (motor control uses it)
What is the basal nuclei responsible for?
initiating movements and inhibiting inappropriate movements
Where is the basal nuclei located?
part of the cerebrum but not the cortex
What is a characteristic of everything in the cerebral cortex?
everything is conscious
What is a characteristic of everything below the cerebral cortex?
everything is subconscious
What is the result of too little dopamine?
Huntington’s disease
What is the result of too much dopamine?
Parkinson’s and inability to produce low movement
What happens when there is basal nuclei damage?
resting tremor
What is the white matter pathway that connects the left and right hemispheres of the brain?
corpus callosum
What are projection fibers?
connections from cerebral cortex down
What are association fibers?
connects part of cerebral cortex with single hemisphere
What is the internal capsule?
connects from cerebral cortex to spinal cord
also an area of white matter that separates the basal nuclei from the gray matter of the diencephalon
What is the limbic system?
a function system that is not necessarily in one place
What structures are found within the limbic system?
hippocampus
fornix
amygdala
limbic lobe
What are the functions of the limbic system?
HOME
homeostasis, olfaction, memory, emotion
What are the functions of the fornix?
primary white matter output tract of the limbic system
What are the functions of the limbic lobe?
emotions
sense of smell tied to memories and emotions- tied together in limbic lobe
What are the functions of the amygdala?
experience and expression of emotions (usually negative)
What are the functions of the hippocampus?
involved in learning and memory
What parts are within the diencephalon?
thalamus
epithalamus
hypothalamus
What is the function of the thalamus?
major relay station for motor and sensory function
helps cortex act as a sensory filter
Who does the thalamus relay info for?
basal nuclei and cerebral cortex
Who does the thalamus filter ascending sensory info for?
primary sensory cortex
What separates the left and right thalamus?
third ventricle
What does the hypothalamus do?
is the coordinator between systems
controls autonomic functions
controls and secretes hormones through the pituitary gland
drives like thirst and hunger
regulates body temp and circadian rhythms
What is the cerebellum involved in?
motor control
What is the cerebellum separated at?
midline by vermis
What are folia?
finer folds in the cerebellar cortex on the surface of the cerebellum
What is the arbor vitae?
white matter of cerebellum
What are peduncles?
white matter connecting cerebellum to pons
myelinated axons go through this
What are the functions of the cerebellum?
motor control
adjusts postural muscles
fine-tunes conscious and subconscious movements
compares what you intend with what is happening
What causes ataxia?
motor error caused by damage to the cerebellum
trauma or stroke
intoxication (temporary)
What does ataxia do?
disturbs muscle coordination
causes intention tremors (tremors with movement)
causes misjudgment of distances
What are the parts of the brain stem?
medulla oblongata
pons
midbrain
What is the brainstem responsible for?
cranial nerves and keeping you alive
Which part of the brainstem is most caudal?
medulla oblongata
What is the middle of the brainstem?
pons
What part of the brain stem is most rostral?
midbrain
What are the 4 D’s of the brainstem?
dysphagia
diplopia
dysarthria
dysmetria
What is dysphagia?
difficulty swallowing
What is diplopia?
double vision
What is dysarthria?
difficulty with muscles of speech
What is dysmetria?
difficulty judging distances
What are the structures of the midbrain?
tectum and tegmentum
What are the 2 pairs of sensory nuclei in the tectum?
superior colliculus (visual)
inferior colliculus (auditory)
What is in the tegmentum?
red nucleus (muscle tone, subconscious motor)
substantia nigra (motor function; dopamine to basal nuclei and other places)
crus cerebri (white matter)
What is the pons?
lots of white matter
involved in motor control
links the cerebellum to the rest of the CNS
has sensory and motor nuclei of cranial nerves 5-7
What is the medulla oblongata?
has white matter tracts
has ascending and descending tracts
has sensory and motor nuclei of cranial nerves 8 to 12
What are the white matter pathways from the cortex to the spinal cord?
medulla pyramids
What are the touch sensory relay centers?
nucleus gracilis and cuneatus
Where is the reticular formation found?
in brainstem but projects to all levels of the brain
What are the functions of the reticular formation?
subconscious regulation of homeostasis
alertness and consciousness
What is the dura mater and where is it found?
outer covering of the brain
tough and fibrous
What are the two layers of the dura mater?
periosteal dura (outer layer)
meningeal dura (inner layer)
What is the arachnoid mater?
layer below the dura mater
connection down to pia mater
What is the pia mater?
the inner layer of the meninges
soft
layer that follows the gyri and sulci
What is the dural reflection and what is its function?
inner layer of the dura mater folding in on itself
provides support
Where are the venous sinuses located?
between the 2 layers of dura mater
veins in the brain empty into the sinuses
How does the blood travel in the brain?
between the 2 layers of dura
What is in the subarachnoid space?
CSF fluid
Where is the falx cerebri located?
down between 2 hemispheres
Where is the tentorium cerebeli located?
below the brain and above the cerebellum
separates the weight of the brain from the cerebellum
Where is the 4th ventricle located?
between the brainstem and cerebellum
What shape are lateral ventricles?
c-shaped
What connects the lateral ventricles and the 3rd ventricle?
the interventricular foramen
What connects the 3rd and 4th ventricles?
the cerebral aqeduct
Where is the 3rd ventricle located?
between the 2 sides of the thalamus
What are the functions of the CSF?
cushioning
support
transports nutrients, chemical messengers, and waste products
How does CSF protect the brain?
filtering plasma
What is the choroid plexus?
part of neuroglial cells called ependymal cells
Ventricles lined with ependymal cells that have choroid plexus
What is the choroid plexus?
filter between blood capillaries and CSF
extra layer for brain
filters plasma to produce CSF in all ventricles
How does CSF flow in the brain?
lateral ventricles to interventricular foramen to 3rd ventricle then more fluid is added then to cerebral aqueduct then to 4th ventricle
Where does CSF go after it reaches the 4th ventricle?
From the 4th ventricle it:
flows down hole in center of spinal cord called central canal
exits from 4th ventricle to subarachnoid space (near brain and cerebellum)
up and around brain and down and around spinal cord
Where does CSF return to venous blood?
arachnoid granulations
Where is the BBB?
on capillaries
How is the BBB formed?
by astrocytes
What happens once arteries to brain divide to reach capillary level?
they exchange and then condense into veins
What are the 4 arteries related to the brain?
2 internal carotid arteries (up to brain)
vertebral arteries (up to brain)
internal jugular veins (drain venous sinuses and return blood to the heart)
Which blood passages travel together?
jugular veins
carotid arteries
How many layers of dura mater does the spinal cord have?
1
What are the 3 meningeal layers of the spinal cord?
dura mater
arachnoid mater
pia mater
What are the meningeal spaces of the spinal cord?
epidural space (between dura mater and vertebrae)
subdural space
subarachnoid space (has CSF)
What is the groove on the back of the spinal cord?
posterior median sulcus
What is the groove on the front of the spinal cord?
anterior median sulcus
Where does the spinal cord end and what is it called?
L1 or L2
conus medullaris is here
What is the filum terminale?
thin thread of fibrous tissue that attaches to the coccyx and secures the spinal cord down
What is the cauda equina?
nerve roots extending below conus medullaris
off spinal cord
Where do nerve roots emerge?
from L5 to sacrum
Where is white matter in the spinal cord?
superficial and has myelinated axons
are the pathways
Where is gray matter in the spinal cord?
surrounds the central canal
has neurons and cell bodies and unmyelinated axons
are the synapses
What do the dorsal horns of gray matter contain?
sensory nuclei
receive info (afferent)
What do the ventral horns of gray matter contain?
lower motor neurons
sends axons out to NMJ
What is the gray commissure?
gray matter that connects the right and left spinal cord
Where does the primary motor cortex synapse?
a neuron in the ventral horn
What do lateral horns contain?
cells bodies of the ANS that go to organs
it is in the thoracic and lumbar segments
How do nerves connect to the spinal cord?
by roots
What does the ventral root have?
axons of motor neurons
What does the dorsal root have?
axons of sensory neurons
What do the dorsal root ganglion contain?
cell bodies of pseudounipolar afferent neurons
What are bundles of axons in the CNS called?
tracts
What do ascending tracts do?
carry info to the brain
sensory (afferent)
contain posterior columns (sense of touch- somato sensation)
spinothalamic (pain and temp)
What do descending tracts do?
carry motor commands to the spinal cord
motor (efferent)
corticospinal (motor)
Where are anterior white columns located?
in front of and between anterior gray horns
Where are lateral columns located?
on sides between posterior and anterior gray horns
What is the anterior white commissure?
where axons can cross from one side of the spinal cord to the other
Where is the 1st order neuron synapse found in the nervous system pathway?
medulla
afferent
ascending
Where does the 2nd order neuron go in the nervous system pathway?
thalamus
thalamus is filter
Where does the 3rd order neuron go in the nervous system pathway?
cerebral cortex
What does the integration in the cerebral cortex?
interneurons
Where are upper motor neuron cell bodies found in the nervous system pathway?
primary motor cortex
descending
sends axon down spinal cord
Where are lower motor neuron cell bodies found in the nervous system pathway?
anterior horn of spinal cord
descending
How does perception enter the CNS?
afferent nerves
Where are the general somatic senses HQ?
parietal lobe (post-central gyrus)
touch, proprioception, pain and temp
What are the posterior columns?
sensory pathways that contain information about touch and proprioception
What kind of neurons are in posterior columns?
pseudounipolar
Where is the neuron 1 cell body in posterior columns?
dorsal root ganglion
How do the neurons travel in posterior columns?
ascend ipsilaterally in the spinal cord
Where do posterior columns synapse?
the medulla
also where the 2nd order neuron is
What does the 2nd order neuron do in posterior columns?
sends axon to the thalamus
Where does the 2nd order neuron decussate in posterior columns?
in the medulla
Where is the 3rd order neuron in posterior columns?
synapses in the thalamus
sends info to postcentral gyrus of contralateral cortex
What info does the spinothalamic tract (ST) carry?
pain and temperature
Where is the neuron 1 cell body in the ST?
dorsal root ganglion
Where does the ST synapse?
dorsal horn of spinal gray matter
also where 2nd order neuron is
What happens after the ST synapses?
the neuron decussates immediately
ascends contralaterally
Where does the 3rd order neuron synapse in ST?
thalamus
Where does the 3rd order neuron send info to in ST?
post-central gyrus
What does the corticospinal tract carry info for?
voluntary motor function
Where does the corticospinal tract begin?
pre-central gyrus (opposite side of muscle we want to move)
upper motor neuron cell body location
How do axons descend in the CT?
through the internal capsule
crus cerebri
medulla pyramids
Where do the neurons decussate in CT?
pyramids
How do neurons travel in CT?
descend ipsalaterally
Where does the CT synapse?
anterior gray horn onto lower motor neuron (synapse of upper motor neuron)
Where does the lower motor neuron synapse in CT?
NMJ
Where are upper motor neurons found in the CNS?
precentral gyrus
synapse in interneurons to lower motor neurons
Where are lower motor neurons found in the PNS?
brain and ventral horn of spinal cord
part of PNS
