A&P unit 4 - CNS

basic pattern organization of CNS

-central cavity surrounded by gray matter core (nuclei)

-external to grey matter is white matter (myelinated axons)

-cerebral hemispheres and cerebellum have an outer "bark" or cortex of gray matter 

cranial meninges

-3 CT layers

-separate and support brain & BV

-help contain and circulate CSF

-in brain AND spinal cord

pia mater

-adhere directly to brain surface

-thin layer of areolar CT

arachnoid mater

-in middle

-arachnoid trabeculae - lines that extend to pia mater

-subarachnoid space - contains CSF

-made of collagen & elastic fibers

dura mater

-tough outer layer, closest to bone

-made of dense CT in 2 layers

-layers usually fused, but in some areas they separate to form dural venous sinuses that drain excess CSF from brain

diagram 2 layers of dura mater

-periosteal layer - closest to bone

-meningeal layer - closer to brain

-CSF drained thru dural venous sinus

4 ventricles image

functions of CSF

-Buoyancy – reduces brain’s weight by 95%​

-Protection – provides a liquid cushion​

-Environmental stability – transport of nutrients / wastes and protects against fluctuations​

ependymal cells

-produce CSF

-have cilia

-line cavities in brain and spinal cord → each ventricle, choroid plexus capillaries

excess CSF

-flows into arachnoid villi, drains into dural venous sinuses

-arachnoid granulation = collection of arachnoid villi

→ if it is not drained properly, can cause edema of brain (meningitis)

horns of the spinal cord

*made of gray matter

the brain runs caudal → rostral. What does this mean?

tail → head

as you move up the brain it gets more complex functions & more evolutionarily advanced

gray matter vs white matter

gray = cell soma, holds nuclei

white = axons, myelinated

name each of the 4 lobes and what they control

frontal = voluntary motor & cognition

temporal = hearing

occipital = vision

parietal = somatosensory

homonculus

term for human model showing how much space in the brain is given up to sensory regions for that specific area in the body

amygdala

location = diencephalon

function =

-negative emotions like fear and anger

-fight or flight

-link emotional reaction to memories

basal nuclei/basal ganglia

gray matter in cerebrum

function =

-initiate movement & suppress unwanted mvmt

-monitor & coordinate slow, sustained contractions

broca’s area

location = frontal lobe, left hemisphere only

function = motor speaking ability → form words

wernicke’s area

location = temporal & parietal lobe, left hemisphere only

function = language comprehension. receives visual & auditory input to understand

cerebellum

function =

-balance

-muscle memory

-execute voluntary motor mvmt

hippocampus

location = diencephalon

function =

-memory formation → learning

-retrieval of long-term memories

thalamus

location = diencephalon

function = sensory relay station before info is sent to cortices

hypothalamus

location = diencephalon, below thalamus

function =

-hormone secretion, sleep/wake cycle (melatonin)

-regulate autonomic internal processes → homeostasis

brainstem

pons, medulla, midbrain

function = autonomic behaviors, and control cardiovascular, respiratory, and digestive systems

primary motor cortex

location = precentral gyrus

function = motor control in body

premotor cortex

location = in front of precentral gyrus/PMC

function =

-orient body to specific target

-plan mvmt before sending to PMC

-coordinate skilled mvmts

primary somatosensory cortex

location = postcentral gyrus

function = relay and process somatosensory info

primary visual and auditory cortices

location = occipital (visual), or temporal (auditory)

function = process visual/auditory info

prefrontal association cortex/PFC

location = frontal lobe

function =

-higher cognition

-thinking, brainstorming, weigh consequences

-working memory

parietal-temporal-occipital association cortex

location = parietal, occipital, temporal lobes

function =

-integrates sensory output from the 3 lobes

-important in language understanding

limbic association cortex

location = temporal, some in the frontal

function = motivation, emotion, memory

functional systems

term for a collection/network of neurons that work together, but span large distances in the brain

→ reticular formation

→ limbic system

reticular formation/reticular activating system

functional system involving the brainstem to thalamus

functions = alert cerebrum of incoming sensory info → promotes alertness and directs attention to events

→ sensory overload occurs with too much info in the RAS being sent

limbic system

functional system involving hippocampus, hypothalamus, thalamus, amygdala

functions =

-emotional activation

-associate emotion to a perceived event

-integrate emotion with memory

short and long term memory

short term = temporary modification to preexisting synapse function

-working memory in PFC

long term = permanent modification to preexisting synapse function

-procedural memory in cerebellum

-involves PFC and hippocampus

LTP

“long term potentiation”

process of strengthening synapse by using the connection more

→ strengthen memories, with LTP we can turn short term to long term or strengthen short term