124 terms


how sensations occur
stimulation of receptors leads to impulses in afferent neuron - pathway leads to cerebral cortex for interpretation
change in environment that initiates response in a receptor
sense receptor
specialized nerve ending or cell which detects a specific change in the environment
simple receptor
specialized ending of nerve cells found throughout the body
complex sense receptor
localized in head and made of distinct receptor cells
where conscious sensation is produced
cerebral cortex
sensations persist after simulus has been removed

sensations are referred to point of stimulation

once a sensation forms, the brain interprets the impulse to have come from the receptors being stimulated -- the brain then projects the sensation back to its source
ex. eye sees object, nose smells food
sensations disappear even though stimulus is still present
information about internal environment
interoreceptors (visceral receptors)
taste, fatigue, hunger, thirst, nausea
interoreceptors (visceral receptors)
information about position + movement
information about external environment
hearing, sight, touch, temperature
sensations that
adapt slightly or not at all
visual receptors (tonic receptors)
general or cutaneous senses
general or cutaneous senses:
simple or complex receptors?
excessive stimulation of sense organ
special senses
special senses:
simple or complex receptors?
location of receptors for
sense of smell
superior nasal epithelium
cranial nerve that carries info
for sense of smell
I cranial nerve (olfactory)
location of receptors for
sense of taste
taste buds embedded in epithelium of tongue
cranial nerves that carry info
for sense of taste
VII cranial nerve (facial)
IX cranial nerve (glossopharangeal)
four basic tastes
salty, sour, bitter, sweet
part of tongue sensitive to each taste
sour = lateral tongue
salty = lateral / tip of tongue
sweet = tip of tongue
bitter = posterior tongue

(this classic map is currently being questioned)
three basic layers of the eye
fibrous tunic (sclera + cornea)
vascular tunic (choroids, ciliary body, + iris)
sensory tunic (retina)
opening in center of iris
thin muscular diaphragm responsible for eye color
clear portion of outermost tunic
allows for light passage
white of eye
changes shape to aid in focusing
fibrous tunic
outermost layer of eye
vascular tunic
middle layer of eye
contains many blood vessels
sensory tunic
innermost layer of eye
layer that contains photoreceptors
fovea centralis
most sensitive portion of innermost layer

"dip" at posterior retina in diagram
optic disc
area where optic nerve exits eye
ciliary body
contains smooth muscle
produces aqueous humor
function of
suspensory ligaments
(attach to lens)
function of iris
regulates amount of light entering eye
function of cones
color vision
function of ciliary body
focus and produces aqueous humor
(contains ciliary muscle to pull suspensory ligament)
function of tears
protection + keep eyes moist
function of
extrinsic eye muscles
move eyeball
function of rods
vision with low light
(gray vision)
function of optic nerve
carries impulses from eye to brain
function of
nasolacrimal duct
allows tears to enter nasal cavity
function of lens
focus light onto retina
function of choroid
vascular - nourishes eye
function of pupil
hole - allows light into eye
function of lacrimal gland
produces tears
function of sclera
provides shape of eyeball
anchor for eye muscles
function of cornea
clear - allows light to enter
regulation of size of pupil
smooth muscle in iris regulates size of opening (pupil)

controlled by autonomic nervous system
--> sympathetic dilates
--> parasympathetic constricts
intrinsic eye muscles
ciliary body
anterior chamber
space in front of lens
space between iris + cornea
posterior chamber
space between lens + iris
aqueous humor
fills spaces (anterior chamber + posterior chamber)
where aqueous humor is produced
ciliary body
function of aqueous humor
supplies nutrients + oxygen to lens and cornea
where aqueous humor drains
scleral venous sinus
(canal of Schlemm)
posterior segment
space behind lens
vitreous humor
gel-like substance present at birth

fills posterior cavity (space behind lens)
function of vitreous humor
transmits light
holds lens + retina in psition
maintains eye pressure
bony cavity in skull that surrounds eyeball
eyelids - skin-covered structures that can be drawn over the eye
mucous membrane lines eyelids + covers cornea
function of conjuctiva
prevents eye from drying out
bending of light
where refraction occurs
definition of
adjustability of lens to focus light onto retina
how accommodation occurs
contraction + relaxation of ciliary muscles alters tension on suspensory ligaments to change shape of lens
definition of
optic chiasm
part of brain where optic nerves cross
what occurs at optic chiasma
crossing over of optic nerves allows medial fibers to cross from one optic tract to the other
where nerve impulses from retina are
interpreted visually
occipital lobe of cerebral cortex
inability to focus lens with aging
decreased transparency of lens
increased intraocular pressure due to blocked drainage of aqueous humor
caused by elongation of eyeball
distortion of visual image caused by irregularity of cornea
inflammation of mucous membrane lining eyelid and covering cornea
caused by short eyeball
detached retina
pulled away from choroid
sense receptors contained in ears
hearing + equilibrium
location of cochlea
inner ear
location of semicircular canals
inner ear
location of vestibule
inner ear
location of
opening to auditory tube
middle ear
location of ossicles
middle ear
location of auricle
outer ear
location of
external auditory meatus
outer ear
function of auditory tube
equalizes pressure on both sides of tympanic membrane (eardrum)
function of auricle
gathers sound waves
function of ossicles
vibrate against oval window
function of stapedius +
tensor tympani muscles
protect against loud sounds -
limit vibrations of ossicles
function of cochlea
sense of hearing
function of organ of Corti
receptor for hearing
function of oval window
vibrates when stimulated by ossicles to cause vibrations in perilymph of cochlea
function of
tympanic membrane
vibrates with sound waves to set up vibration in ossicles
function of round window
at end of cochlea
dampens vibrations to prevent reverberation into cochlea
function of
external meatus
carries sound waves to tympanic membrane
function of vestibule
sense of equilibrium (utricle + saccule monitor position of head when head is not moving)

static equilibrium
function of
semicircular canals
sense of equilibrium (monitor position of head when head is moving)

rotational equilibrium
glands in
external auditory meatus
ceruminous glands
what ceruminous glands produce
ear wax to trap dust + repel insects
separates outer and middle ear
tympanic membrane
names of the ossicles
connected by the
auditory tube
middle ear cavity + pharynx
nerve that transmits info
concerning balance + hearing
VIII cranial nerve (vestibulocochlear)
where nerve impulses from the
organ of Corti are interpreted
temporal lobe of cerebral cortex
otitis media
middle-ear infection
danger of otitis media
can block sound waves (hearing loss)
may spread to mastoid sinus (meningitis)
fluid that fills membranous labyrinth
fluid that fills osseous labyrinth
structures that make up
the labyrinth
vestibule + semicircular canals
receptors in cochlea
hearing receptors
receptors in vestibule +
semicircular canals
vestibular receptors (balance)
how sound is changed
into a nerve impulse
hair cells in organ of Corti bend to create nerve impulse
how info concerning
balance + position is transmitted
mechanoreceptors in semicircular canals + vestibule are hair-like projections that bend to create an impulse
"mismatch of sensory input"
involuntary movements of the eye that may be associated with chronic inner ear disorder (Meniere's disease)
motion sickness
disorder of equilibrium where particular motion leads to nausea + vomiting
nerve deafness
due to damage to hair cells of organ of Corti or auditory pathway to brain
conduction deafness
sound vibrations not conducted to inner ear
can be due to blocked external acoustic meatus, ruptured eardrum, or osteosclerosis (overgrowth of bone in middle ear)