ch 17 Flashcards
special senses
smell
taste
vision
balance
hearing
olfaction
sense of smell
2 layers of nasal cavity
olfactory epithelium
lamina propria
odorants
small airborne organic water-soluble or lipid-soluble substances which stimulate the olfactory receptors
olfactory sensory nurons
highly modified nerve cells
gustation
sense of taste
lingual papillae
epithelial projections on the surface of the tongue
filiform papillae
- found on front 2/3 of tongue
Provide friction to move food around mouth and do not contain taste buds
fungiform papillae
- scattered along the tip and sides of tongue
5 taste discriminations
sweet
salty
sour
bitter
umami
palpebral fissure
gap that separates the free margins of the upper and lower eyelids
tarsal glands
modified sebaceous glands along the inner margin of the eyelid
lacrimal caruncle
mass of soft tissue at medial angle of eye, which contains glands producing thick secretions
conjunctiva
epithelial membrane of eye
types of conjunctiva
palpebral: covers inner surface of the eyelids
bulbar: covers the anterior surface of eye
lacrimal apparatus
produces, distributes, and removes tears
lacrimal gland
tear gland/produces tears
lacrimal sac
collects tears from lacrimal canaliculi
nasolacrimal duct
conducts tears from the inferior portion of the lacrimal sac to the nasal cavity
layers of the eyeball
- fibrous - outer
- vascular - middle
- inner layer
whats contained in the fibrous layer
cornea and sclera
whats in the vascular layer (3)
iris
cilliary body
choroid
inner layer
neural layer
pigmented layer
sclera
white of the eye
cornea
transparent most anterior part of the eye
iris
colored part of the eye
pupil
opening of iris that allows light into the eyeball
photoreceptors
cells that detect light
rods
allow for vision when light is low
cones
provide color vision
bipolar cells
neurons that synapse with the rods and cones
ganglion cells
neurons that synapse with bipolar cells
horizontal cells
form a network that extends across the neural layer at the level of the photoreceptor-bipolar cell synapses
amacrine cells
form a network that extends across the neural layer at the level of the bipolar ganglion cell synapses
optic disc
origin of optic nerve
- eyes blind spot, no photoreceptors
aqueous humor
fluid that circulates within the anterior cavity and diffuses through the posterior cavity
vitreous body
gelatinous mass in the posterior cavity
lens
transparent, biconvex, flexible disc that lies posterior to the cornea
cataracts
loss of transparency in the lens due to injury, U V radiation, drug effects or ageing
refraction
light is bent as it passes from one medium to another
focal distance
distance between the center of the lens and the focal point
astigmatism
the light passing through the cornea and lens is not refracted properly and the visual image is distorted
accommodation
lens changes shape of eye to provide clear vision
- Becomes rounder to focus on nearby objects
- flattens to focus on far objects
visual acuity
– clarity of vision compared to a “normal” standard
2020 vision
