Chapter 9: The General and Special Senses Flashcards
astigmatism
irregular shape in the lens or cornea that can affect light refraction and clarity of the visual image
presbyopia
farsightedness caused by loss of elasticity of the lens of the eye due to aging
presbycusis
age related hearing loss
ultraviolet keratitis
severe pain, tearing, light sensitivity, and foreign-body sensation that occurs after ocular exposure to extremely bright light
acute glaucoma
failure of aqueous humor to enter the canal of Schlemm; rise in intraocular pressure leading to soft tissue distortion within the eye
nerves responsible for taste
facial, glossopharyngeal, vagus; “spicy” is transmitted by trigeminal nervetaste receptors are found in tongue, larynx, pharynx
receptive field
area monitored by a single receptor cell; the larger the receptive field, the less precise the information
adaptation
reduction in sensitivity in the presence of a constant stimulus
6 general senses
temperature, pain, touch, pressure, vibration, proprioception
5 special senses
olfaction, gustation, vision, equilibrium, hearing
nociceptors
pain receptors; especially common in superficial portions of the skin, joint capsules, periostea, and around blood vessels
slow pain
unmyelinated fiber; burning/aching sensations
fast pain
myelinated fiber; prickling pain
referred pain
felt in a location other than where it originates
thermoreceptors
respond to changes in temperature; common in dermis, skeletal muscles, and the liver; cold receptors are 3-4x as numerous as warm receptors
Mechanoreceptors
-sensitive to stimuli such as stretching, compression, or twisting
-tactile receptors
-baroreceptors
-propioreceptors
free nerve endings
sensitive to touch and pressure, situated between epidermal cells
root hair plexus
made up of free nerve endings that are stimulated by hair displacement
tactile discs
“Merkel’s discs”fine touch/pressure receptors located in deepest epidermal layer of hairless skin
tactile corpuscules
“Meissner’s corpuscules”sensitive to fine touch/pressure/low-freq vibrations; abundant in eyelids, lips, fingertips, nipples, external genitalia
lamellated corpuscules
“pacinian corpuscules”large receptors sensitive to deep pressure and to pulsing/high-freq vibrations; common in skin of fingers, breasts, external genitalia
Ruffini corpuscles
sensitive to pressure and distortion of the skin; located in deepest layer of the dermis
baroreceptors
provide information essential to the regulation of autonomic activities by monitoring changes in pressure; consist of free nerve endings embedded within elastic tissues in organs, such as the bladder or blood vessels
propioreceptor
monitor the position of joints, tension in tendons/ligaments, and the state of muscular contraction
Golgi tendon organs
lie between a skeletal muscle and its tendon, monitor the strain on a tendon during muscle contraction
chemoreceptors
respond to water-soluble and lipid-soluble substances that are dissolved in the surrounding fluid
olfactory epithelium
contains olfactory receptor cells, supporting cells, regenerative (basal) cells
olfactory glands
secretions coat surfaces of olfactory organs
primary taste receptors
sweet, salty, bitter, sour, umamifront–>back
taste buds
taste receptors + specialized epithelial cells
papillae
epithelial projections which protect taste buds from mechanical stresses of chewing
gustatory cells
slender sensory receptors
accessory structures of the eye
Eyelids, eyelashes, eyebrows, lacrimal apparatus, and extrinsic eye muscles
palpebrae
eyelids
medial/lateral canthus
corners of the eye where upper/lower eyelids connect
tarsal glands
modified sebaceous glands, secrete a lipid-rich substance that keeps the eyelids from sticking together
lacrimal caruncle
located at medial canthus; contains glands that produce thick secretions (“eye boogers”)
sty
infection of an oil gland of the eyelid
conjunctiva
Delicate membrane lining the eyelids and covering the eyeball
conjunctivitis
pinkeye; inflammation of the conjunctiva
six extrinsic eye muscles
superior rectus
inferior rectus
lateral rectus
medial rectus
superior oblique
inferior oblique
fibrous tunic
the outermost layer of the eye, consisting of the cornea and sclera and connecting with eye muscles
sclera
“white of the eye”
cornea
the transparent layer forming the front of the eye; continuous with the sclera
vascular tunic
middle layer of the eye; contains choroid, ciliary body, iris, and blood/lymphatic vessels
iris
a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening
neural tunic
retina, innermost layer of the eye; made up of pigmented and neural parts
rods
detect black/white; peripheral/night vision
cones
detect color; require brighter light, focused in macula lutea
macula lutea
“yellow spot” central area of the retina that is rich in cones and that mediates clear, detailed vision
optic disc
blind spot, location where optic nerve attaches, no photoreceptor cells
anterior chamber of eye
filled with aqueous humor
posterior chamber of eye
filled with vitreous humor
accommodation
the process by which the eye’s lens changes shape to focus near or far objects on the retina
photoreceptors
detect photons
visual pigments
-absorb photons
-make up outer segments of the discs found in both rods and cones
-derived from compound rhodopsin
rhodopsin
formed by retinal and opsin
retinal
pigment synthesized from vitamin A; identical in rods/cones
opsin
protein portion of rhodopsin; different forms are found in rods and each of the three types of cones (red/blue/green)
auricle
“pinna”external portion of the ear
ceruminous glands
produce ear wax
tympanic membrane
eardrum
auditory tube
eustachian tubechannel between the middle ear and the nasopharynx
auditory ossicles
malleus, incus, stapes
bony labyrinth
winding tunnels located in the inner ear; protects the membranous labyrinth
endolymph
fluid within the membranous labyrinth
perilymph
fluid between the bony and membranous labyrinths
vestibule
portion of the bony labyrinth that contains the utricle and saccule; sensitive to linear acceleration
semicircular canals
Encole semicircular ducts (3); stimulated by rotations of the head
cochlea
contains cochlear duct which provides sense of hearing
dynamic equilibrium
aids us in maintaining our balance during movement
static equilibrium
maintains our posture and stability when the body is motionless
ampulla
Swollen region of the semicircular canals that contains the sensory receptors (hair cells)
maculae
sensory receptors for acceleration found in vestibule; contain otoliths
organ of corti
hair cells of the cochlear duct are located here; sits above basilar membrane
frequency of a sound
number of cycles per second (hertz); high frequency = high pitch
Outer ear
-External acoustic canal
-Tympanic membrane
Middle ear
-Auditory tube
-Auditory ossicles (M.I.S.)
Inner ear
-Bony labyrinth
-Membraneous labyrinth
