Topic 19 Central Nervous System PPT Pt 1

Central Nervous System

Brain and Spinal Cord

Rostral

toward forehead

caudal

toward cord

longitudinal fissure

divides cerebral hemispheres

gyri

folds

sulci

grooves

cortex

surface layer of gray matter

nuclei

deeper masses of gray matter

tracts

bundles of axons

gray matter

neuron cell bodies, dendrites, and synapses

function of gray matter

forms cortex cerebrum and cerebellum

forms nuclei deep within brain

white matter

bundles of axons

function of white matter

forms tracts that connect parts of brain

meninges

dura mater, arachnoid layer, pia mater

dura mater

outermost, tough

epidural space filled with fat in low back, subdural space

arachnoid layer

subarachnoid space, SF surrounding this layer

pia matter

innermost layer

meningitis

inflammation of the meninges

bacterial or viral invasion of the CNS via nose and throat

signs: fever, stiff neck, drowsiness, headache

cerebrospinal fluid

formed by the choroid plexus

cerebrospinal fluid function

cushion for brain

buoyancy to brain prevents brain from crushing under own weight

transports nutrients, chemical messengers, and waste

application hydrocephalus

if CSF becomes obstructed, can cause condition

order of circulation of cfs

inter ventricular foramen - connects LV and 3rd V

Cerebral aqueduct connects 3rd and 4th V Fourth ventricle

hydrocephalus

enlargement of the head in babies and brain damage in adults

flow of cerebrospinal fluid

csf circulates from choroid plexus, through ventricles, to central canal of spinal cord, into subarachnoid space around brain

coup contrecoup

primary impact - the brain strikes the skull on the side of impact

secondary impact - contrecoup impact posterior area of skull

returning CSF from subarachnoid space to venous circulation

arachnoid villi - extensions of subarachnoid space, extend through dura mater to superior sagittal sinus

arachnoid granulations - large clusters of villi, absorb CSF into venous circulation

blood brain barrier

BBB includes the endothelium and surrounding cells

specialized capillaries help prevent unwanted stuff from getting into brain

circumventricular organs

pituitary gland - fenestrated capillaries: big holes so stuff can get through