bridging units y9 Flashcards
what are 4 physical defences?
skin, nose, trachea, cilia in throat
what are 2 chemical defences?
hydrochloric acid in stomach, lysozymes in tears
explain the defence of the skin
has antimicrobial secretions, its a physical barrier that prevents microbes from entering the body
explain the defence of the nose
traps particles and stops them from getting into your mouth
explain the defence of the cilia in the throat
waft mucus with pathogens in them to the back of the throat where they can be swallowed
explain the defence of the trachea and bronchi
secrets mucus that trap pathogens
explain the defence of the hydrochloric acid in the stomach
has a low pH of 2 which destroys most pathogens that enter via the mouth
explain the defence of the lysozymes in tears
prevent microbes from entering the eye
how does information go from the retina to the brain?
-photoreceptor cells in the back of the retina turn the reflected light into an electrical signal
-this is then transmitted from the retina to the brain via the optic nerve
describe how an impulse passes from a relay neurone to the motor neurone
-when the electrical impulse reaches the terminal of the relay neurone, neurotransmitters diffuses across the synapse
-when they reach the dendrites of the motor neurone then a new impulse is generated
how can you hear sound?
-sound waves are created by an object as it vibrates
-the pinna funnels the wave into the ear drum to vibrate
-these are passed into the ossicles
-the ossicles pass them to the cochlea where electrical signals are generated
signals pass thru the auditory nerve tot he brain
if the pitch of a sound is increased what difference does it make to how the eardrum vibrates?
the eardrum will vibrate quicker
explain how the a person’s ear can be damaged by loud sounds
loud sounds can rip the eardrum
in what form is information passed form the ear to the brain
electrical impulses
what part of the nervous system carries information from the ear to the brain?
the auditory nerve
