bridging units y9

Question 1

what are 4 physical defences?

Answer 1

skin, nose, trachea, cilia in throat

Question 2

what are 2 chemical defences?

Answer 2

hydrochloric acid in stomach, lysozymes in tears

Question 3

explain the defence of the skin

Answer 3

has antimicrobial secretions, its a physical barrier that prevents microbes from entering the body

Question 4

explain the defence of the nose

Answer 4

traps particles and stops them from getting into your mouth

Question 5

explain the defence of the cilia in the throat

Answer 5

waft mucus with pathogens in them to the back of the throat where they can be swallowed

Question 6

explain the defence of the trachea and bronchi

Answer 6

secrets mucus that trap pathogens

Question 7

explain the defence of the hydrochloric acid in the stomach

Answer 7

has a low pH of 2 which destroys most pathogens that enter via the mouth

Question 8

explain the defence of the lysozymes in tears

Answer 8

prevent microbes from entering the eye

Question 9

how does information go from the retina to the brain?

Answer 9

-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

Question 10

describe how an impulse passes from a relay neurone to the motor neurone

Answer 10

-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

Question 11

how can you hear sound?

Answer 11

-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

Question 12

if the pitch of a sound is increased what difference does it make to how the eardrum vibrates?

Answer 12

the eardrum will vibrate quicker

Question 13

explain how the a person’s ear can be damaged by loud sounds

Answer 13

loud sounds can rip the eardrum

Question 14

in what form is information passed form the ear to the brain

Answer 14

electrical impulses

Question 15

what part of the nervous system carries information from the ear to the brain?

Answer 15

the auditory nerve