Not in GCSE Flashcards
Label the brain
A= cerebral cortex B=medulla C=Optic nerve D=cerebellum
Cereberal cortex function
Controls memory, intelligence, langugae and conciousness
Cerebelum function
Control muscular coordiation
Medulla function
Cotrol unconcious activities
How does the eye focus on far away objects
1) ciliory muscles relax 2)Suspensory ligaments tighten 3)Lens becomes thinner so light rays are refracted weakly
What is myopia
Short sightedness, when lens becomes too curved, light focused in front of the retina so images apper blury far away
Treatment for myopia
glasses with concave lens, which spreads light rays out, so can be focused on retina
what is hyperopia
Long-sightedness, lens is too flat, light focused behind retina so images appear out of focus when close
Treatment for hyperopia
lasses with convex, brings light rays together, so can focused on retina
2 types of contact lenses
hard- rigid material, lastslong and must always be kept sterile soft-flexible material that last for shorter time, but are more comfortable
What is laser eye surgery
Use of lasers to fix visual defects in adults
Laser eye surgery for myopia
lasers reduce tickness of cornea so light refacted less strongly
Laser eye surgery for hyperopia
lasers alter curvature of cornea so light is refracted correctly
Risks of lens replacement
retina damage, infection, cataracts
What is lens replacement
Treats hyperopia, natural lens removed ad artificial, clear, plastic is inserted
Function and structure of retina
light stimulates retina ells, impulses sent to brain, light sensitive layer at back of eye
Function and structure of sclera
Protects internal structures, tough outer layer of eye
Lable the eye
A= suspensory ligaments B= retina C=optic nerve D=sclera E=ciliary muscle F=lens G=pupil H=cornea I=iris
Function and structure of cornea
Lets light into eye and allows light to be focused onto retina cirved transparent layer at front of eye
Function and structure of iris
Controls size of pupil by contracting and relaxing, allows eye to adjust to bright and dim light, muscle
How iris alters pupil in bright light
Circular muscles contract, redial muscles relax, pupils smaller to avoid retinal damage
How iris alters pupil in dim light
Circular muscles relax, radial muscles contract, pupils get larger so more light can enter eye
What is accommodation
Alteration of lens’ shape to focus on near or distant object
How eye focuses on nearby object
Ciliary muscles contact, suspensory lgaments loosen, lens becomes thicker and more curved-light rays refracted strongly
Job of platelets
Help clot blood and stop pathogens entering