Topic E: Nervous Control

Question 1

muscles and glands can act as effectors

Answer 1

antagonistic muscle: one contracts, the other relaxes

ex: triceps relax while biceps contract to lift arm

Question 2

sense organs

Answer 2

groups of receptor cells responding to specific stimuli

ex: hand, ear, tongue, eye, nose

Question 3

eye parts

Answer 3

cornea: protects eye surface & focuses light rays
dispensary ligaments: holds lens in place
lens: focuses light on retina
iris: regulates amount of light entering eye
ciliary muscles: change shape of lens
optic nerve: transmits impulses to brain
retina: has cones & rods to sense light
vitreous humour: clear so light passes, holds shape
aqueous humour: supports lens

Question 4

eye defects

Answer 4

farsightedness: can’t see near, light focuses after retina
nearsightedness: can’t see far, light focuses before retina
astigmatism: distorted image, had multiple focal points

Question 5

the ear

Answer 5

pinna: amplifies sound
ear canal: acts as funnel to transmit sound
ear drum: vibrates in response to sound waves then transmits vibrations to ossicles
semi-circular canals: balance (liquid that moves in response to movement of head: one for shaking, one for nodding, and one for side to side)
oval window: membrane-covered, transmits vibrations from ear drum
round window: moves allowing movement of fluid within cochlea leading to moving of cochlea cilia
cochlea: fluid-filled, translates vibrations of auditory sound into impulses the brain understands (contains fluid and cilia)
Eustachian tube: (or throat tube) keeps constant pressure and drains infections

Question 6

reflex arc

Answer 6

neural pathway that controls a reflex action
(sensory stimulus receptor -> sensory neuron -> cell body -> relay neuron -> synapse -> motor neuron -> motor end plate -> muscle contracts)