Unit 1 Test Flashcards
hairlike receptors on the ends of neurons
dendrites
basic unit of the nervous system
neuron
long extension leading away from the cell body
axon
fatty layer of tissue that surrounds an axon
myelin sheath
gaps between myelin on the axon
nodes of ranvier
cells that help to make up the myelin sheath
schwann cells
gap between neurons
synapse
neuron that receives incoming stimuli
interneuron
neuron connected to a muscle (effector) that carries out an impulse
motor neuron
firing of a neuron, also known as depolarization
action potential
minimum stimulus required to cause a response
threshold level
neuron will completely fire or not at all
all or none response
exitatory neurotransmitter found in synapses of neurons, stimulates skeletal muscle and inhibits cardiac muscle
acetylcholine
outer region of the brain (cerebrum), involved in thought and reasoning
cerebral cortex
part of the brain stem, regulates many involuntary activities including increasing heart rate
medulla oblongata
region of the brain that controls motor coordination and balance
cerebellum
relay centre between the medulla and the cerebellum
pons
band of white matter that connects the two cerebral hemispheres, relay center between left and right hemispheres
corpus callosum
nerve tissue that is myelinated
white matter
nerve tissue that is unmyelinated
grey matter
protective membranes that cover the brain and spinal cord
meninges
made up of the brain and spinal cord
central nervous system
made up of nerves supplying the brain and spinal cord
peripheral nervous system
nerve root that is connected to a sensory neuron in the spinal cord
dorsal root
nerve root that is connected to a motor neuron
ventral root
part of the ans, prepares the body for emergencies
sympathetic nervous system
part of the ans, brings the body back to normal after an emergency
parasympathetic nervous system
enzyme that destroys acetylcholine in a synapse
cholinesterase
pump in a neuron that actively removes ions after an action potential, removes 3Na+ ions for every 2K+ ions it brings in
sodium/potassium pump
region of the brain responsible for motor functions and senses
parietal lobe
region of the brain that is involved in thought and reasoning
frontal lobe
region of the brain that is responsible for sight
occipital lobe
region of the brain responsible for hearing
temporal lobe
paralysis of two limbs
parapelegic
paralysis of four limbs
quadrepelegic
normal state that an axon is at, normally -70 mV outside of neuron js + while inside is -
resting potential
process of reversing the normal charge in an axon, outside becomes - while the inside becomes +
depolarization
process of restoring the original arrangement of ions in an axon, done with the help of the sodium/potassium pump
repolarization
period when no other action potentials can occur, the axon is restoring its original arrangement of ions
refractory period
the path a reflex takes
reflex arc
the action carried out as a result of a reflex
reflex act
reflex of the knee
patella reflex
reflex of the bottom of the foot
babinski reflex
reflex of the pupil
pupillary reflex
group of natural pain killers produced by the body to reduce pain
endorphins
thin layer of transparent tissue on the front of the eye, helps to focus light onto the lens
cornea
hard clear structure in the eye that focuses light onto the retina
lens
layer of protective tissue on the inside of the eyelid; serves to protect the front of the eye
conjuctiva
clear fluid in the front chamber of the eye
aqueous humour
clear fluid in the posterior portion of the eye
vitreous humour
layer of tissue at the back of the eye, where light is focused. it contains rods and cones
retina
outer layer of the eye, serves to protect the eye
sclera
middle layer of tissue in the eye, serves to prevent scattering of light in the eye
chloroid layer
region at the back of the eye where there is a large concentration of rods and cones
fovea centralis
region where the optic nerve enters the eye, no rods or cones here therefore no vision
blind spot
sensory nerve that carries impulses to the brain
optic nerve
the colouring tissue of the eye, serves to control the amount of light entering the eye
iris
the opening into the eye, where light passes through the lens
pupil
photosensitive cells in the retina that detect low levels of light and are mainly used at night
rods
photosensitive cells in the retina that are used for detecting colour and bright light
cones
the process of the lens changing shape to account for viewing near and far objects
accomodation
near sightedness, caused when the eye is too long
myopia
far sightedness, caused when the eye is too short
hyperopia
pigment needed in order for the cones and rods to detect light
Rhodopsin
vision problem where there is too much pressure in the eye, caused by irregular draining of vitreous and aqueous humours
glaucoma
vision defect because of irregular curvature of the lens or cornea
astigmatism
outer fleshy part of the ear, directs sound waves to the auditory canal
pinna
long canal that leads from the pinna to the tympanic membrane, serves to amplify sound waves
auditory canal
thin membrane found at the end of the auditory canal, changes sound energy into mechanical energy
tympanic membrane
group of three small bones in the ear that conduct mechanical waves in the ears, called the hammer-malleus, anvil-incus, and stirrup-stapes
ossicles
tube that leads from the middle ear to the back of the throat, serves to equalize pressure in the ear
eustachian tube
small layer of tissue that covers the opening of the cochlea, receives waves from the stapes
oval window
snail-shaped structure in the ear that is filled impulses to the brain
auditory nerve
set of three fluid filled canals that control dynamic balance
semicircular canals
small bones in the inner ear that detect the position of the head, static balance
otoliths
small fluid filled sacs that contain otoliths in the inner ear
saccule/utricle
hormone released by a pineal gland, associated with sleeping
melatonin
found in the pancreas, lowers blood sugar levels
insulin
fight or flight hormone, increases blood sugar and constricts blood vessels
adrenaline
increases heart rate and causes muscles to contract
noradrenaline
the maintaining of a constant internal enviroment by reacting to stimuli, reactions can be carried out by any system in the body
homeostasis