lab 11 Flashcards
what are the general senses?
- the somatic senses (touch, pressure, pain, temperature, and proprioception)
- visceral senses which provide information about our internal organs
- special senses: vision, hearing, equilibrium, taste and smell
what does adipose tissue function as on the eye?
adipose tissue functions as padding and insulation within the orbit to protect the eye
function of sclera on the eye
sclera consists of dense fibrous connective tissue that forms the tough external coat
-functions to protect and shape the eyeball and provide a study anchoring site for extrinsic eye muscles
function of the cornea on eye
allows light to enter the eye and helps bend light rays so they are focused on the photoreceptors in the retina
what is the fluid found behind the cornea
aqueous humor- it maintains intraocular pressure/ inflates the globe of the eye
what is the iris
the iris is the circular coloured portion of the eye that lies anterior to the lens.
- consists of 2 layers of muscle (inner circular and outer radial smooth muscle)
function of the choroid
absorbs excess light rays to prevent reflection and scattering of the light within the eyeball
function of the fovea centralis
the area of greatest visual acuity containing only cones
causes of glaucoma
increased pressure to the optic nerve can cause glaucoma- permanent vision loss
what is a cataract?
medical condition where the lens of the eye becomes progressively opaque, resulting in blurred vision
what is accomodation
the lens of the eye must become round in shape to view objects in close range
define near point
the closest distance at which an object apears to be in sharp focus
define visual acuity. what test would you use to determine visual acuity?
refers to the degree of sharpness of eyesight.
- standard test for determining this is the SNELLEN TEST- measured in a fraction. what you can see/ what the general population can see.
hyperopic eye characteristics
caused by an eyeball that is too short.
- individual with this see distant objects clearly but but close objects are out of focus.
- need a converging lense to INCREASE refraction refer to notes for diagram
myopic eye characteristics
caused by an eyeball that is too long
- can see close objects clearly but distant objects are blurry
- need a diverging lens to DECREASE refraction
what is an astigmatism
an astigmatism is irregular curvature of the cornea/lense.
what test would you use to predict colour blindness?
standard pseudoisochromatic colour blind test
what does the external ear do?
collects sound waves and channels them inwards
what does the middle ear do?
the middle ear transfers sound vibrations to the oval window and
- equalizes pressure with external atmospheric pressure
what does the inner ear do?
contains the receptors for hearing and equilibrium
what are the main subdivisions of the internal ear?
1) bony labyrinth
2) memranous labyrinth
about the bony labyrinth:
bony labyrinth: system of chambers within the temporal bone that contains perilymph fluid.
-3 regions include 1) cochlea 2)vestibule 3) semicircular canals
about the membranous labyrinth:
membranous labyrinth lies within the bony labyrinth and consists of interconnecting sacs and ducts filled with endolymph fluid.
- receptors for hearing are located within the cochlear duct while the recepters for equilibrium are located within the saccule, utricle (static eq.) and semicircular ducts (dynamic eq.).
about equilibrium
equilibrium sensations provide information about the position of the head in space by monitoring gravity, acceleration, and roation.
- has 2 components: static and dynamic equilibrium
vestibule
has receptors involved in maintaining static equilibrium
what is middle ear deafness?
a loss of hearing from failure to conduct sound waves and vibrations from the outer to inner ear
- weber test tests for middle ear deafness
- rhine test- holding it against the mastoid process which measures bone conduction
taste
a chemical taste first dissolves in saliva and then stimulates the hairs of taste cells that emerge from a taste pore in the taste bud.
5 primary tastes: sweet - from sugars, sour - citric acid, bitter-caffeine, salty- metal ions like sodium or potassium, umami- meaty/savoury taste
