Sensory System

Sensory System
STUDY
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Lacrimal Gland
tears empty into the nasal cavity
Conjunctiva
thin membrane that lines the eyelids and covers part of the eye, secretes mucous to lubricate eye
Extrinsic Muscles
Muscles responsible for moving the eye are attached to the sclera
Sclera
outer layer,white of the eye,tough coating helps maintain shape of the eye and protects what's inside
The eye
1" in diameter, protected by the orbital socket of skull, eyebrow, eyelashes and eyelids bathed in fluid from the lacrimal gland
Cornea
front of sclera -- clear part (no blood vessels)
transparent so light rays can pass through
Gets oxygen through lymph
Choroid Coat
middle layer, contains blood vessels
Iris
colored, muscular layer surrounding the pupil
Intrinsic Muscles
change size of iris to control amount of light entering through the pupil
Lens
crystalline structure located behind iris and pupil; elastic, disc-shaped, bioconvex; situated between the anterior and posterior chambers
accommodation
change in the shape of the lens to allow for near and distant vision
anterior chamber
filled with aqueous humor
aqueous humor
watery fluid
posterior chamber
filled with viteous humor
viteous humor
transparent, jellylike substance
Retina
innermost layer, light rays focus an image on the retina the image travels to ther cerebral cortex via
Optic Nerve
if light rays don't focus properly on the retina,corrective lenses can bend the light rays as required retina contains specialized cells-rods and cones
Rods
sensitive to dim light
Cones
Sensitive to bright light and color
Optic Disc
On the retina, known as the blind spot- nerve fibers gather here to form the optic nerve rods no rods or cones
Pinna (AURICLE)
outer ear collects SOUND
Tympanic Membrane
ear drum , separates outer and middle ear
Middle Ear
cavity in temporal bone connects with the pharynx by the eustachian tube- which equalixes pressure in the middle ear with the outside atmosphere bones in the middle ear that transmits sound waves from the ear drum to the inner ear
1. MALLEUS (hammer)
2. INCUS (anvil)
3. STAPES (stirrup)
Inner ear
contains the spiral shaped organ of hearing
Cochela
the cochela contains a membranous tube, the cochlear duct-which is filled with fluid that vibrates when sound waves are transmitted by the stapes
Organ of Corti
Delicate hairlike cells that pick up vibrrations of fluid and transmit them as a sensory imoulse along the auditory nerve to the brain
Nose
Smells accounts for 91% of taste tissue in the nose, olfactory epithelium, contains specailized nerve cell receptors
Tongue
mass of muscle tissue bumps on the surface area papillae they contain taste buds receptors in taste buds send stimuli through 3 cranial nerves to the cerebral cortex`
pink eye
inflammation of conjunctival membranes in front of the eye redness ,pain ,swelling and discharge, highly contagious, Rx-anibiotics, eye drops
Glaucoma
excessive intraocular pressure causing destruction of the retina and atrophy of the optic nerve caused by over production of aqueous humor lack of drainage or aging, symptoms develop graduall- mild aching loss of peripheral vision, halo around the light
Tonometer
measures intraocular pressure
Cataracts
lens of the eye gradually becomes cloudy frequently occurs in people over 70 causes a painful,gradual blurring and loss of vision pupil turns black to milky white
Rx surgical removal of the lens
Sty
abscess at the base of the eyelash symptoms red,painful and swollen
Rx- warm, wet compresses
Eye Injuries
tears are effective in cleaning the eye if glass or fragments get in the eye cover both eyes amd see medical treatment
Color Blindness
cones are affected- genetic disorder that is carried by the female and transmitted to males
Presbyopia
lens loses elasticity, can't focus on close or distant objects usually occurs after age 40
Rx- bifocals
Hyperopia
farsighted focal point beyond the retina because the eyeball is too short convex lenses help
Myopia
nearsighted eyeball is to long concave lenses help
Astigmatism
irregular curvature of the cornea or lens, causing blurred vision and eye strain Rx:corrective lenses
Diploia
double vision
Strabismus (cross eyes)
eye muscles do not coordinate their action usually in childre Rx: eye exerise or surgery
Ophthalmoscope
Instument for veiwing inside the eye
Snellen eye Chart
chart that uses letter or symbols in calibrated heights to check for vision defects
Tinnitus
ringing in the ears from impacted wax
Otits Media
infection of the middle ear often a complication of a common cold in children Rx- antibiotics
Myringotomy
opening in the tymphanic membrane
Otosclerosis
chronic progressive middle ear disorder stapes becomes spongy and then hardens becoming fixed and immobile common cause of deafness in young adults Rx-stapedectomy smd total replacement of stapes
Presbycusis
deafness due to the aging process, can be helped with the use of hearing aids
Types of hearing loss
Conductive-which sounds are prevented from reaching inner ear
Sensorineural-problem with inner ear or auditory nerve
Rhinitis
Inflammation of the lining of the nose with nasal congestion, drainage, sneezing and itching caused by allergies, infection, fumes, odors, emotion or drugs