Nervous System and Special Senses

CNS

brain and spinal cord

PNS

cranial nerves and spinal nerves

neuron

nerve cell

dendrite

branch that receives impulses

axon

fiber that sends impulses away from the cell body

myelin

fatty sheath that speeds nerve conduction

synapse

gap between neurons

neurotransmitter

chemical that carries a signal across a synapse

cerebrum

largest part of the brain for thought and voluntary movement

cerebellum

coordinates movement and balance

medulla oblongata

controls breathing and heart rate

thalamus

relay center for sensory impulses

hypothalamus

controls temperature and hunger and thirst

meninges

three membranes that cover the brain and spinal cord

cerebrospinal fluid

cushions the brain and spinal cord

sympathetic system

fight or flight response

parasympathetic system

rest and digest response

CVA

stroke

TIA

temporary stroke like episode

epilepsy

disorder with recurrent seizures

Parkinson disease

tremor and slowed movement

Alzheimer disease

progressive memory loss

multiple sclerosis

destruction of myelin in the CNS

meningitis

inflammation of the meninges

encephalitis

inflammation of the brain

hydrocephalus

excess cerebrospinal fluid in the brain

concussion

brain injury from a blow

neuralgia

nerve pain

neuropathy

disease of the nerves

aphasia

loss of the ability to speak or understand

ataxia

lack of muscle coordination

syncope

fainting

paresthesia

abnormal sensation such as tingling

cephalalgia

headache

lumbar puncture

needle placed in the spinal canal to remove fluid

EEG

record of brain electrical activity

cornea

clear front covering of the eye

sclera

white of the eye

conjunctiva

membrane lining the eyelids

iris

colored part of the eye

pupil

opening in the center of the iris

lens

focuses light on the retina

retina

light sensitive layer at the back of the eye

optic nerve

carries visual impulses to the brain

rods

retinal cells for dim light

cones

retinal cells for color

myopia

nearsightedness

hyperopia

farsightedness

astigmatism

blurred vision from an irregular cornea

presbyopia

age related loss of near vision

cataract

clouding of the lens

glaucoma

increased eye pressure that damages the optic nerve

conjunctivitis

pink eye

strabismus

misaligned eyes

diplopia

double vision

photophobia

sensitivity to light

tonometry

measurement of eye pressure

tympanic membrane

eardrum

ossicles

three small ear bones (malleus and incus and stapes)

eustachian tube

connects the middle ear to the throat

cochlea

organ of hearing

semicircular canals

organs of balance

otitis media

middle ear inflammation

tinnitus

ringing in the ears

vertigo

sensation of spinning

audiometry

hearing test