ch 13 CNS-brain (i hate this)

CNS

brain and spinal cord

sensory (afferent) INPUT; has somatic sensory and visceral sensory

somatic sensory

sensations from the skin

EX. touch/vibration, pain, heat/cold

visceral sensory

sensation from visceral organs

EX. pain stomach, kidney, bladder; sensation is taken from visceral fibers → brain

PNS

spinal and cranial nerves (outside brain and spine)

motor (efferent) OUTPUT; has somatic motor and visceral motor

somatic motor

voluntary actions

EX. skeletal muscle (walking and talking)

visceral motor

control of involuntary actions

EX. heart beat, lungs, GI tract (automatic, cannot control)

also has the ANS! (sympathetic and parasympathetic)

nervous system

nervous system formed from ectoderm (ectodermic origin), dorsal in position, hollow due to cavities (filled with CSF)

@ 3-4 weeks; thickening of ectoderm on dorsal side of embryo (nervous system formation)

notochord

eventually makes vertebral column

somites

muscles of the back

cephalic part

makes the brain

caudal part

makes the spinal cord

primary brain vessicles

@ 12 weeks; everything completes (prosencephalon, mesencephalon, rhombencephalon) and spinal cord

secondary brain vesicles

derived from primary brain vesicles

telencephalon, diencephalon, midbrain, metencephalon, myelencephalon

telencephalon

cerebral hemispheres (LARGEST PART OF BRAIN)

forebrain (corpus callosum, gyri, sulci, fissures (longitudinal and transverse)

convolutions as they grow

diencephalon

thalamus (80% of diencephalon), hypothalamus (pituitary), and epithalamus (pineal gland)

forebrain

midbrain

carpora quadrigemina (the butt inside the brain tbh.) (SMALLEST PART OF THE BRAIN)

carpora quadrigemina

THE BUTT IN THE BRAIN

4 swellings on dorsal side of brain, made up of superior and inferior colliculi

metencephalon

pons and cerebellum

hindbrain

mylencephalon

medulla oblongata

hindbrain

medulla oblongata

continues as the spinal cord, which exits brain and cranium thru froamen magnum (up to L1)

flexure

notch/depression appears so it can bend

major flexures of the brain

cephalic (midbrain), cervical, and pontine/ventral (memorize image)

anencephaly

baby is born without a brain, just the brain stem

able to survive since breathing and cardiovascular centers are present BUT sensory and motor receptors are missing

no voluntary control, cannot talk and cannot see

microcephaly

SMALL BRAIN

parts of brain can be present, but too small

can be caused by ZIKA VIRUS

hydrocephalus

brain/head is TOO LARGE

too much CSF; if too large before birth, baby cannot exit birth canal

ventricles of brain

extensions of embryonic neural canal (4 ventricles)

surrounded by ependymal cells

1st and 2nd ventricles/lateral ventricles

in cerebral hemispheres

extend into occipital and temporal lobes

very large, “C” shaped

communicate to 3rd ventricle thru interventricular foramen/foramen of monroe

3rd ventricle

in diencephalon

many capillaries (choroid plexus; a capillary bed)

secretes CSF

uses cerebral aqueduct to talk to 4th ventricle

4th ventricle

in pons and cerebellum

choroid plexus is here which secretes CSF

continues into spinal cord as central canal

cerebral spinal fluid

protection against mechanical shock (shock absorption)

helps brain float (buoyancy)

ionic balance

circulates through all ventricles → goes into central canal of spinal cord → then goes out and around the brain and around spinal cord

reabsorbed back into blood through arachnoid villi to superior midsagittal sinus and inferior sinus

median aperture

magendie foramen (where CSF circulates thru)

Luschka foramina

2 lateral apertures (CSF circulates thru here)

dura mater

fibrous, tough, leathery; periosteal layer only in brain

meningeal layer around brain and spinal MORE FIBROUS

arachnoid

like spider web

pia mater

most delicate, innermost layer, sticks → nervous tissue

blood vessels to supply brain

meningitis

inflammation of meninges (bacterial or viral), such as encephalitis

encephalitis

too much CSF, makes brain swell, must be drained through spinal tap

hydrocephalus

excess of CSF

has to be taken out with a catheter; put into ventricle to drain out CSF

arachnoid villi

extension of arachnoid mater through dura mater and into superior sagittal sinus

allows CSF to be reabsorbed by venous system

subdural space

betw. dura mater and arachnoid mater

subarachnoid space

betw. arachnoid mater and pia mater

contains CSF

go into villis and back into blood

CSF continuously made and goes back into blood

septum pellucidum

separates the 2 lateral ventricles in the 2 cerebral hemispheres

convolutions

wavy structures on the top of brain; MORE convolutions = MORE neurons and nervous tissue

gyrus

elevations

sulcus

shallow depression

cerebral cortex

has millions of neurons, most important part of the brain ; abt 6 mm thick (covered by pia mater)

makes gray matter (where neurons are and has unmyelinated nerve fibers)

white matter

NO neurons, but has myelinated nerve fibers

median longitudal fissure

separates 2 halves of the brain

transverse fissure

separates cerebral hemispheres from cerebellum

falx cerobrae

between 2 lobes of cerebrum

falx cerebelli

betw. 2 lobes of cerebellum

tantorium cerebelli

betw. cerebellum and cerebrum, in transverse fissure

insula

not visible externally, covered by temporal lobes

perceives gustatory

central sulcus

separates frontal from parietal lobes (horizontal)

parieto-occipital sulcus

deep groove that separates the occipital and parietal lobes (in the back)

deep lateral sulcus

temporal-parietal and frontal (on the sides)

cranial fossae

depressions in the skull

post central gyrus

primary somato sesnsory cortex

where ALL sensory input is received

EX. touch, vibration, heat, cold, pain (NOT TASTE SMELL VISION)

precentral gyrus

makes primary motor cortex (controls ALL voluntary muscles)

if damaged, PARALYSIS

anterior fossae

frontal lobes

middle fossae

temporal lobes

posterior fossae

cerebellum

primary motor cortex

frontal lobe; also the precentral gyrus and controls voluntary/skeletal muscle

premotor cortex

frontal lobe, skilled movements, control of limbs and torso

EX. playing instrument/typing

frontal eye field

frontal lobe, control of extra ocular muscles

prefrontal cortex

in FOREHEAD, where personality, behavior, multitasking, cognition, intelligence, memory, creativity

primary visual cortex

occipital lobe; image processing

primary auditory cortex

sound perception/processing; temporal lobe

primary gustatory cortex

taste perception, insula

primary somato-sensory cortex

perceive sensations in post central gyrus—sensory input (NOT taste, vision, hearing, smell); parietal lobe

brocais area

controls speech, motor speech, articulate speech; tongue muscles; LEFT FRONTAL LOBE

wernikes area

comprehension of written and spoken language; LEFT SUPERIOR TEMPORAL LOBE

brocais/expressive aphasia

issue saying words, knows what to say but cannot say words/short phrases

wernike’s/receptive aphasia

doesn’t understand language, uses long sentences and makes up words

aprosodia

facial expressions and what a person is saying doesn’t match

association areas

integrate info from diff sources into a single thought

gnostic area

general interpretation area

brain’s ability to recognize info that’s been perceived before

corpus callosum

interconnects cerebral hemispheres, large tract of white matter

fornix

like a bridge, interconnects regions of cerebrum with mammillary bodies

somatotrophy

drawing a human figure on the brain; have to identify sensory and motor areas (Homunculus)