B3.1 Flashcards
cornea
-transparent coating in eye
-protects light from entering
pupil
-hole in eye
-lets light enter
-dilates in dim light, contracts in bright light
iris
-coloured ring of muscles
-relaxes/controls pupil
lens
-transparent bio convex lens
-focuses light on rtina
ciliary muscle
-ring of muscle tissue
-alters shape of lens
suspensory ligaments
-ligament tissue
-connects ciliary muscles to the lens
optic nerve
-nervous tissue
-carries nerve impulse to brain
myopia
-short sightedness
-caused by lens being too strong/ eyeball too long
-fixed by conCAVE lens:
bends light rays outwards before they enter the eye
hyperopia
-longsightedness
-lens is too weak/short eyeball
-fixed by conVEX lens:
light rays bend inwards
focus on nearby objects
-ciliary muscles contract
-lens become more convex
focus on faraway objects
-ciliary muscles relax
-convex lens (thinner)
rods
-respond to light
-lets u see in dim light
cone
-responds to colours
how does light enter the eye
1)cornea refracts so focus is on incoming light
2)light passes by pupil
3)further refracted by lens
4)sharp image on retina
5)photoreceptors on retina produce impulse
6)impulse goes through optic nerve to the brain
cerebrum
memory,senses, vocab, personality…etc
cerebellum
muscle coordination, balance, posture (movement)
medulla
auto actions, like heart rate and breathing
hypothalamus
regulates temp and h20 balance
pituitary
stores and releases hormones
studying the brain
CT SCANS:
-use x-rays to create 3d images inside brain
MRI SCANS:
-use magnets to scan for abnormalities
difficulties with brain researcg
-ethics about animal testing (can’t consent)
-difficult in getting people for case studies
-brain tissue is delicate and could be harmed easily
Nervous system damage
caused by:
-injury
-disease
-genetic conditions
-toxic substances
effects of nervous system damage
-can’t detect pain
-numbness
loss of coordination
effects of nervous system damage (PNS)
-can’t detect pain
-numbness
loss of coordination
