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47 terms

Ch 9: Senses

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general senses
receptors for these senses are distributed throughout body;
eg, pain, touch, temperature, and proprioception (body position)
special senses
receptors for these senses found in specific organ;
eg, taste, smell, vision, hearing, balance
sensation
detection of a stimulus by a receptor and the conduction of that stimulus to the CNS
perception
conscious awareness of a sensation within an organism's brain/mind
chemoreceptor
detect chemicals;
eg gustatory (taste) and olfaction (smell) receptors
photoreceptor
detect light energy;
eg vision receptors
mechanoreceptor
detect physical movement or pressure;
eg auditory (hearing) and equilibrium (balance) receptors
nociceptors
detect pain;
found throughout the skin and some internal organs
thermoreceptor
detect temperature;
found throughout the skin and in hypothalamus
vision
sense of sight;
detects light energy (photons)
conjunctiva
mucous membrane lining eyelids and covering anterior sclera
lacrimal gland
glands superior and lateral to eyes that secrete tears to lubricate & cleanse the eye
sclera
fibrous outermost layer of the eye; envelops entire eye except cornea portion; "whites" of eye
cornea
hard, fibrous transparent structure covereing the iris and pupil
choroid coat
highly-vascularized darkly pigmented middle layer of eyeball; absorbs excess light to prevent it from interfering with vision
iris
colored portion of eye; allows light through the pupil (hole in iris) to reach the retina
pupil
"black" hole in iris, where light that passes through is focused by the lens onto the retina
lens
elastic, transparent disc-shaped structure that focuses light onto the retina
ciliary body
muscles of the lens
aqueous humor
watery liquid anterior to lens, posterior to cornea;
too much is causes glaucoma
vitreous humor
transparent jelly filling posterior chamber of eyeball;
holds retina in place
glaucoma
condition in which aqueous humor drains improperly, accumulates in anterior chamber, elevating intraocular pressure; leads to loss of vision / blindness
retina
innermost neural layer of the eye, where photoreceptors are
cone
color-detecting photoreceptor;
humans have cones tuned to either red, green, or blue
rod
light-detecting photorceptor; work only in low-light conditions; does not distinguish colors
macula lutea
center of the retina, where photoreceptors are conctrated; appears as a yellow spot on retina
fovea centralis
pit in center of macula, where cones are highly concetrated; dead center in one's field of vision
pathway of light
source/subject → cornea → pupil (past iris) → lens → retina
auricle
fleshy, visible part of the ear;
directs sound waves into auditory canal;
aka pinna
auditory canal
ear canal connecting auricle to tympanic membrane; aka external auditory meatus
tympanic membrane
membrane in ear that sound vibrates onto ossicles;
aka ear drum
middle ear
air-filled cavity containing ossicles;
behind tympanic membrane until cochlea; connected to pharynx via eustachian tubes
auditory ossicles
3 smallest bones in body, transmit sound waves from outer ear (ear durm) to inner ear (cochlea):
malleus (hammer)
incus (anvil)
stapes (stirrup)
eustachian tube
"auditory tube" connecting middle ear to pharynx (throat); equilizes pressure inside middle ear with outside
cochlea
hearing organ of the inner ear; contains mechanoreceptors in organ of Corti that detect sound waves
semicircular canals
inner-ear organs that detect head rotation
vestibule
inner-ear organ detects balance, head tilt and forward-backward motion
pathway of sound
ear canal → tympanic membrane → ossicles → cochlea → cochlear nerve (auditory nerve)
olfaction
sense of smell;
detects chemicals dissolved in air
sensory adaptation
reduction of perception of a constant harmless stimulus;
eg, "get used to a smell"
gustation
sense of taste;
detects chemicals dissolved in foods & liquids on tongue
taste bud
contain chemoreceptors that detect dissolves chemicals; found in tongue papillae
5 tastes
sweet
salty
sour
bitter
umami (meaty or savory)
touch
mechanoreceptors detect physical forces that deform or move tissue (eg skin);
similar to sense of pressure
proprioception
sense of body position, orientation, and location; receptors in tendons, ligaments, and muscles
temperature
detection of temperature outside & inside the body; deteceted by thermoreceptors
pain
detected by nociceptors located throughout body (eg skin); stimulated by tissue damage