Nervous System and Eye Flashcards
Receptor
detects stimulus changing its energy into electrical energy of the nerve impulses.
Types of receptors
retina (eye) > light
ear > sound
ear(balance) > kinetic
tongue > chemical
nose > chemical
skin(touch/pressure/pain) > kinetic
skin(heat) > heat
muscle (stretch receptors) > kinetic
Stimulus and Response process
stimulus > receptor > coordination > effector > response
draw motor neurone 5 parts. explain
cell body: in the CNS, contains nucleus, form a junction with other neurones
dendrites: thin protrusions. form junctions with other neurones
myelin sheath: insulation. made of lipids. prevent ‘short circuiting’
axon
draw a sensory neurone 6 parts
junctions with sensory receptors
dendron
axon
myelin sheath
cell body
junction with neurones in cns
draw a motor neurone 6 parts
cell body
dendron
dendrites
myelin sheath
axon
axon terminations on effector eg muscle fibre
speed of nerve impulse
10-100 m/s speed of charged ions moving in axon
draw eye 12
Conjunctiva
Cornea
Iris
Ciliary muscle
Suspensorio ligaments
Lens
Retina
Choroid
Fovea
Sclera
Optic nerve
Vitreous humour
how light is focused on retina
cornea and lens refract light
iris reflex
bright: circular contract radial relax
dark: circular relax radial contract
accomodation
focus on near and far objects
near: suspensory ligaments slacken, ciliary muscles contract, rounded lens = more refraction
far: suspensory ligaments tighten, ciliary muscles relax, flatter lens = less refraction
reflex arc
stimulus > receptor > generate impulses in sensory neurone dorsal root > synapse with relay neurone in the cns > synapse with motor neurone travels in ventral root > sends impulse to effector > effector carries out an action
synapses
electrical nerve impulse reaches end of neurone
triggers neurotransmitters to diffuse across synapse
neurotransmitter attaches to cell membrane
impulse continues in second neurone
enzymes break down neurotransmitter from second neurone
