The Nervous System

Fxs of the nervous system

1. sensory input
2. motor input
3. evaluation and integration
4. homeostasis
5. mental activity

CNS

brain and spinal cord

PNS

nerves all over the body outside the CNS

sensory division of PNS

afferent NN carry messages to spinal cord and brain

motor division of PNS

efferent NN carry messages from CNS to organs

ANS

visceral motor division. carries signals to glands and smooth MM

two divisions of ANS

parasympathetic
sympathetic

SNS

carries signals to skeletal MM. voluntary control.

-nom-

law

nerv-

nerve

neur/o-

nerve

-pathet-

suffering

peripher-

outer part

sens-

feel

somat-

body

-eon

one who does

-ery

process of

-ory

having the function of

______ receive stimuli and transmit impulses to other NN or receptors in other organs

neurons

_____ are branched extensions of the cell body. conduct impulses toward the cell body

dendrites

____ are nerve fibers that carry impulses away from the cell body. they are covered by myelin sheaths

axon

groups of cell bodies outside the CNS group together to form ______

ganglia

axons combine together to form ______

nerves

-morphin

morphine

myel-

spinal cord

-mitt-

to send

ser/o

serum, serous

-ton-

tension

-apse

clasp

-lemma

covering

-er

agent

-ine

pertaining to

4 types of neuroglia in CNS

1. astrocytes
2. oligodendrocytes
3. microglia
4. ependymal cells

astrocytes

most abundant glial cells. transport water and salt to NN

oligodendrocytes

form myelin sheaths around axons. bundles of these axons are 'white matter'

microglia

phagocytose bacteria and cell debris

ependymal cells

line central canal of spinal cord and ventricles in brain

2 types of neuroglia in PNS

1. neurolemmocytes
2. satellite cells

neurolemmocytes

Schwann cells. form myelin sheaths around PNS nerves

satellite cells

found around neuron cell bodies

Blood Brain Barrier

physical barrier to prevent foreign substances from entering the brain

astr/o

star

cerebr/o

brain

fluid

flowing

cerebell-

little brain

cerebr-

brain

-glia

glue

-lemm/o

rind, husk

-dendr/o

tree-like

callos-

thickening

pariet-

wall

3 major regions of the brain

cerebrum, brain stem, cerebellum

cerebrum

80% of brain. consists of 2 cerebral hemispheres separated by the corpus callosum

brain stem

relays sensory impulses from peripheral nerves to higher brain centers. controls heart and lung function

cerebellum

posterior of brain. maintains posture and balance

4 lobes of cerebral hemispheres

1. frontal lobe
2. parietal lobe
3. temporal lobe
4. occipital lobe

thalamus

receives sensory impulses and channels to correct region for interpretation

hypothalamus

regulates BP, body temp, water and electrolyte balance, hunger and weight, sleep and wakefulness, movement and secretion of digestive tract

basal nuclei

collections of gray matter that control volume muscle movement, posture, emotion, and cognition

limbic system

controls emotional experience

brainstem

controls pons and medulla oblongata

audit-

hearing

gloss/o

tongue

ocul/o

eye

trochle-

pulley

olfact-

smell

opt-

eye

-gemin-

double, twin

4 regions of spinal cord

1. cervical region
2. thoracic region
3. lumbar region
4. sacral region

3 layers of meninges

1. dura mater
2. arachnoid mater (CSF contained here)
3. pia mater

arachn-

cobweb, spider

mater

mother

equin/a-

horse

cervic-

neck

dur/a

hard

pia

delicate

dementia

not normal. not a specific disease

Alzheimer disease

most common form of dementia. affects 10% of pop. neurons associated with memory are replaced with abnormal clumps of protein

vascular dementia

2nd common form of dementia. may come on gradually or suddenly

delirium

sudden onset of disorientation

ischemic strokes

90% of strokes

atherosclerosis

plaque in wall of cerebral artery

embolism

blood clot in cerebral artery

microangiopathy

occlusion of small cerebral arteries

hemorrhagic strokes

occur when blood vessel in brain bursts or a cerebral aneurysm of AVM ruptures

hemiplegia

paralysis of one side of the body

cerebral palsy

motor impairment resulting from brain damage. not hereditary.

diplegia

paralysis of corresponding parts on both sides of the body

epilepsy

chronic disorder. clusters of neurons discharge their electrical signals in abnormal rhythms

focal seizures

epileptic activity in one area of the brain

generalized onset seizures

occur on both hemispheres of the brain

absence seizures

"petit mal". ages 4-14. child stares vacantly for 10 secs ish

tonic-clonic seizures

"grand mal". loss of consciousness, breath stops, muscles stiffen, lasts 1-3 minutes

febrile seizures

triggered by high fever in infants to 5 year olds

status epilepticus

brain is in state of persistent seizure. 10+ minutes or 3 recurrent seizure without regaining consciousness between

syncope

fainting due to hypotension and hypoxia of the brain

cataplexy

sudden loss of voluntary muscle tone with brief episodes of total paralysis

Parkinson disease

caused by degeneration of neurons in the ganglia that produce dopamine hand tremors, rigidity, shuffling gait

Huntington disease

hereditary disorder starting with mild personality changes between 30-50. involuntary, jerky movements and muscle weakness follow

primary brain tumors are _____

gliomas