special senses Flashcards
Site of olfactory receptors
In mucosa of superior region of nose
Three types of olfactory cells
olfactory receptors
supporting cells
basal cells
Consist of olfactory hairs with chemoreceptors
These are first order neurons of olfactory pathway
olfactory receptors
Epithelial cells: support, protect
supporting cells
. stem cells that produce new neurons (receptors) throughout life.
basal cells
Pathway for Olfaction
Olfactory nerves
Olfactory bulb
Olfactory tract
Olfactory cortex
Located on tongue, pharynx, epiglottis
In structures called papillae
receptors in taste buds
Five primary tastes
salt, sweet, sour, bitter, and umami
pathway of tears
Lacrimal glands lacrimal ducts surface of upper eyelid surface of eye
Lacrimal canals lacrimal sac nasolacrimal duct nasal cavity
accessory structures for protection and lubrication (blinking)
eyelids
accessory structures for protection from foreign objects and perspiration
eyebrows and eyelashes
Formation of Image on Retina: Four Steps
refraction
accommodation
constriction
convergence of eyeballs
bending of light rays as they pass from medium of one density to another of different density
Image is inverted but brain adjusts and interprets distance and size
refraction of light
Lens adjusts shape for distance to allow image to focus on retina
accommodation
For distant objects, ciliary muscle
________, __________ lens
relaxes
flat
For closeup vision, ciliary muscle ____, ____ lens
contracts
fat
can see near but not far objects
myopia
Eyeball is too long so lens cannot accommodate enough to focus images of distant objects onto retina
myopia
can see far but not near
hyperopia
Eyeball is too short so lens cannot accommodate enough to focus images of near objects onto retina
hyperopia
irregular curvature of cornea or lens
astigmatism
: aging change loss of elasticity of lens farsightedness reading glasses
presbyopia
These disorders can be corrected with
lenses or LASIK
LASIK
laser assisted in situ keratumileusis
