5.1 Causes of Disorders Flashcards
What 3 sections is the ear composed of
The outer layer (pinna and ear canal)
The middle ear (ossicles and ear drum)
The inner ear (the cochlea and auditory nerve and the brain)
What does the ear drum do when sound enters the ear in waves
vibrates
Why does conductive hearing loss occur
when there is a damage to the outer or middle ear, resulting in ineffective sound transfer
What may be the cause of conductive deafness
An ear infections, otosclerosis (abnormal bone growth in ear) or perforation of the ear drum
What may the cause be of sensorineural hearing loss
occurs when there is a damage to the inner ear. Sound may arrive at the cochlear, but is not properly passed on to the auditory nerve, or this may be damaged itself
may be congenital
or other factors such as age, gender, noise exposure etc
hearing loss may be a combination of both …
conductive and sensorineural
where does light firstly enter the eye
the cornea, a clear curved ‘window’ on the front of the eye
What does the cornea do
refracts light through the pupil, an opening at the front of the eye, the width of which is controlled by the movement of the iris
What can pupils do
Able to dilate and contact, the shape of the iris changing how much light enters the eye
What does the lens do
it is a curved, flexible structure which focuses light by shortening and lengthening its width
what is the globe of the eyeball filled with
vitreous gel
a dense transparent substance that gives the eye its spherical shape whilst still allowing light to be transmitted to the back of the eye
Where do light rays come too
focal point
where the image is focused, at the retina in the back of the eye
what cells is the retina composed of
rods and cones
these cells enable light energy to be converted into electrical impulses
which send the message onto the optical nerve and through the brain for processing
Refractive errors
occur when the eye does not focus light properly, due to incorrect shaping of the cornea
Myopia (or near sightedness)
Occurs 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.
far away objects a blurry
Hyperopia (or 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, due to misshapen cornea where curvature is not uniform in all directions
What are other prevalent eye disorders
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 do kidneys do
the body’s cleaners, processing blood to filter out waste products and balance salt and water levels
What are waste products collected as
Urine
which moves from the kidneys to the bladder through the ureters, and then out of the body through the urethra
where does blood enter and exit the kidney
through the rebel artery and out the renal vein
What are the main areas of the kidney
Cortex (outermost layer)
Medulla (petal-like inner structures)
pelvis (drainage area at centre of kidney, connected to ureter)
how is filtering performed
by microscopic structures called nephrons, situated across the cortex and the medulla.
Every kidney has about one million nephrons
What do capillaries do
they are wound around the nephron structures providing an interface across which exchange of nutrients may occur
What would happen if loss of kidney function occurs
may result in build-up of wastes, electrolytes and dangerous levels of fluid in the blood.
it is possible to lose up to 90% of kidney function before noticeable symptoms occur
What might be the result of kidney failure
Diabetes
High blood pressure
Inflammation of important filtration structures
Obstruction of kidney
Infections
