Health chapter 3: keeping a sound mind

neurology

the study of the nervous system

central nervous system

the brain and the spinal cord

peripheral nervous system

consists of the nerves

neurons

the actual nerve cells of the body

cell body

contains a nucleus, sends and receives nerve impulses, and controls the cell’s growth

dendrites

branching extensions from the cell that receive impulses from other neurons and send them to the cell body

axons

carries nerve impulses away from the cell body

synapse

the axon of one neuron connects to the dendrites of another neuron

neurotransmitter

messages from one neuron to another by special chemicals

sensory neurons

transmits information to the CNS from the senses as well as pain signals

motor neurons

relays signals from the CNS to other parts of the body

interneurons

found only in the CNS and are responsible for information processing by the brain and spinal chord; they also function to relay messages from place to place within the CNS

brain

the most important and complex part of the nervous system

cerebrum

involved in conscience thought, memory, and interpreting sensory information

cerebellum

controls skeletal muscles during complex movements such as running and swimming

brain stem

controls involuntary muscles and activities in your body such as breathing and heartbeat

limbic system

a part of the brain that helps generate and regulate emotions and coordinate overall brain activity

thalamus

a nerve impulse that is to and from the cerebrum

spinal chord

a thick bundle of nerve fibers in the spinal chord

frontal lobe

associated with sonality, judgement, and self-control

parietal lobes

analyzes the senses and sensations of temperature, pressure, and pain and to make judgement about such things as shape and texture

occipital lobes

responsible for vision

temporal lobes

associated with the senses of hearing, taste, and smell

madulla oblongata

contains nerve centers that regulates breathing, blood pressure, swallowing, and other vital body functions

midbrain

helps coordinate the movements of both eyes

reticular formation

an intricate network of neurons that serves as the “master switch” of the cerebrum

thalamus

routes nerve impulses to and from the cerebrum

hypothalamus

controls your body’s automatic system

reflex

the muscle jerk from something dangerous like heat or sharp objects after contact

spinal nerves

the 31 pairs of nerves located in the spinal chord

cranial nerves

the 12 pairs of nerves that branch directly from the brain

sensory neurons

neurons which relay messages to the spinal chord

motor neurons

relay messages from the spinal chord to all parts of the body

somatic nervous system

responsible for functions that you can control

automatic nervous system

the main body functions that you do not control consciously

sympathetic

stimulates organs when you’re active

parasympathetic

stimulates organs while you rest

sensory receptors

information obtained and relayed to the spinal chord or brain

pain receptors

a bare nerve ending that reacts to a particular type of strong stimulus

mechanoreceptors

the sensory receptors responsible for sensations of touch and pressure

mechano

means mechanical or having to do with physical forces

therm or thermo

means heat

chem or chemo

means chemical

hypo

means “less than, beneath, or below”

scler or sclero

means hard

thermoreceptors

responds to heat and cold

heat receptors

sensitive to temperatures above normal body temperature

cold receptors

sensitive to temperatures below normal body temperatures

chemoreceptors

nerve endings sensitive to chemicals

sclera

the white of the eye

cornea

the transparent portion at the front of the eye

iris

the colored part of the eye

pupil

the opening in the center where light comes through

lens

the part of the eye that focuses the rays of light which pass through it

retina

the thin layer of light-sensitive nerve cells

rod cells

extremely sensitive to light and enable us to see in near-darkness

cone cells

distinguishes between the different colors of light

optic nerves

a large bundle of nerve fibers that carry the rob and cone cells to the occipital lobe

myopia

the inability to clearly focus on distant objects

hyeropia

the inability to clearly focus on nearby objects

astigmatism

an abnormally shaped cornea can also cause a focusing problem

my or myo

refers to muscle

op or ops

refers to the eye

ia

means condition

outer ear

the part of the ear that you can see

auditory canal

it consists of a sound-gathering trumpet and a short tube

eardrum

a thin membrane that is stretched tightly across the end of the auditory canal like a drum

middle ear

a small, hollow chamber within the temporal bone of the skull

inner ear

consists of a snail-shaped, fluid-filled chamber within the temporal bone

cochlea

the temporal bone

auditory

refers to hearing

decibels

the units that scientists often rate the loudness of sounds with

sensorineural deafness of nerve deafness

partial or complete hearing loss caused by excessive or prolonged exposure to loud sounds