The senses Flashcards
Anatomy of the eye
Fluid filled
Three layers
What are the three layers of the eye?
Outermost - sclera and cornea
Middle - Chororid, ciliary body, iris, lens
Innner - Retina, fovea
Optic disk
Reflection
Percieve light waves reflected off objects
Refraction
if not perpendicular, light waves bend as they pass from one medium denisty to another
Pupil size
Iris consists of two layer of smooth msucle (inner circular muscle and outer radial muscle)
The retina
Neural tissue
Contains photoreceptors
Three layer
What are the three layers of the retina
Outer - photorecpetors
Middle - bipolar cells
inner - ganglion cells
Retinal cells
Rods and cones are receptors cells
Rods and cones communicate with bipolar cells
Bipolar cells communicate with ganglion cells
Axons of gangolian cells form the optic nerve
Clinical issues in vision
Myopia - near - sightedness
Hyperopia - far - sightedness
Presbyopia - hardening of lens
Cataract - discoloration of lens
Glaucoma - incraesed volume of aqueous humor
Astigmatism - irregularities of lens or cornea
Emmetropia - normal vision
Antamony of the ear
Outer ear - entry f sound waves
Middle ear - amplification of sound waves
Inner ear - transduction of sound energy
Eustachian tube
Sound waves
Requires a medium to propagate
sounds are produced by vibration of partocles
sound travels as waves which are vibrating praticles
Sound waves are refleted by surfaces
SOund transduction
Sound waves strike tympanic membrane
Causes movemnt of ossicles
Causes movemnt of oval window
Mechanisms of sound transduction
Sterocilia of hair cells connected by protein bridges
Mechanical stress moves protein bridges, causing the opening or closing of cation channels
Cation channels allow cations, expecially potassium to move through
Nerves of the ear
Hair cells = receptor cells
Vestibular nerve relays info related to motion and posititon
Deafness
Conductive deafness
Sensorineural deafness
Central deafness
