Module 8: Technologies and Disorders Flashcards
The ear is composed of what three sections?
inner ear, middle ear, outer ear
What makes up the inner ear?
the cochlea, the auditory nerve, and the brain
What makes up the middle ear?
ossicles and ear drum
What makes up the outer ear?
pinna and ear canal
Explain how sounds are heard
- sound enters ear in form of waves and the ear drum vibrates
- vibration movement causes the ossicles to move in chain like fashion
- this movement ‘knocks’ on membrane window of cochlea
- fluid in cochlea moves in response to knock
- hair cells lining the cochlea are bent in response to fluid vibrations, creating electrical impulse that is sent along the auditory nerve and to the brain
Conductive hearing loss
occurs when there is damage to the outer or middle ear, resulting in ineffective sound transfer.
Can result from ear infections, abnormal bone growth in middle ear, or perforation of eardrum
Sensorineural hearing loss
occurs when there is damage to the inner ear. sound is not properly passed onto auditory nerve, or the nerve itself is damaged.
damage can be result of genetic factors, or disease, or due to age, noise exposure, physical trauma, or menangitis.
Examples of visual disorders
Refractive errors, myopia, hyperopia, astigmatism, glaucoma, cataracts
Explain how the eye sees
light enters through cornea, pupils dilate and contract to control how much light enters eye. light passes through lens which focuses the light through lengthening or shortening its width.
light rays come to a focal point where image is focused at the retina. light energy is converted into electrical impulses by rods and cones - sending messages into optical nerve and through to the brain for processing.
Refractive errors
occur when the eye does not focus light properly, due to incorrect shaping of the cornea
Myopia
(near sightedness) occcurs when the cornea is too curved or the eyeball is too long, resulting in light refracted at an angle which places the focal plane in front of the retina. Objects far away are blurry.
Hyperopia
(far sightedness) occurs when the cornea is too flat or the eyeball is too short, resulting in light being focused beyond the retina. Close up objects are blurry.
Astigmatism
is a disorder where vision is blurred at all distances, as a result of a misshapen cornea where curvature is not uniform in all directions.
Glaucoma
blindness due to a build up of pressure in the eye, causing optic nerve damage.
Cataracts
clouded areas in the lens, causing blurry or tinted vision.
What is the function of kidneys?
process blood to filter out waste products and balance salt and water levels.
waste products are collected as urine which moves to the bladder and exits body through urethra.
What does blood enter and exit the kidneys through?
enters kidney through the renal artery, leaves via the renal vein.
Main areas of the kidney
cortex (outmost layer of the kidney), medulla (petal-like inner structures), and pelive (drainage area at centre of kidney, connected to ureter).
How is filtering performed in the kidneys?
by microscopic structures called nephrons - situated across the cortex and the medulla.
Explain the how kidneys function
when blood enters kidney, capillaries are wound tightly into a glomerulus - squeezing out all fluid except red blood cells into the bowmans capsule. in the proximal convoluted tubule, essential molecules are transferred back to the capillary. the rest of the nephron structure performs and balancing function, regulating the return of salts back into the blood. all wastes are then drained to collecting duct, leading to the renal pelvis to then be drained out of kidney and body.
What are the effects of losing kidney function?
build up of wastes, electrolytes, and dangerous levels of fluid in the blood.
What is kidney failure usually a result of?
diabetes, high blood pressure, inflammation of important filtration structure, obstructin of kidney, infections
What are cochlear implants?
electronic devices which replace the function of damaged inner ears.
What do cochlear implants do?
it enables sound, received through an external transmitter, to be transferred to the auditory nerve, allowing individuals who have damaged the hair cells of the inner ear to hear.
