nerves and sensitivity Flashcards
central nervous system
brain
spinal cord
coordinates all of nervous responses such as moving or reflexes
peripheral nervous system
contains all other nerves which send impulses to all effectors
motor neurones
nucleus- genetic info
dendrite- connect to different neurones
cell body- main section (contains nucleus)
axon- long section in which signal is sent
myelin sheath- sections along neurone which wrap around axon
reflexes
automated actions which do not involve brain
very fast and include sensory, relay and motor neurones
reflex arc
movement of impulse from receptor to effector
stimulus-receptor-sensory-relay-motor-effector-response
synapse
gap between neurones
cornea
curved transparent disc
most of focusing
pupil
circular opening whose size is controlled by iris
coloured part of eye
iris
ring of muscles with hole in middle
iris controls how much light enters
lens
soft, flexible and transparent
shape can be changed to fine tune the focusing of light onto the retina
ciliary muscles
ring of muscles at edge of eye which circles lens
when contracts it gets fatter
when relaxes it gets thinner
suspensory ligaments
strong fibres which attach lens to ciliary muscles
retina
contains light sensitive cells called rods and cones
optic nerve
consists of many neurones which carry impulses from retina to brain
fovea
region of retina with greatest number of cones
