Nervous System, Includes Eye

Question 1

what does the CNS consist of

Answer 1

brain and spinal chord

Question 2

what does the PNS consist of

Answer 2

sensory and motor neurons

Question 3

steps in responding to a stimulus

Answer 3

1.receptors detect a stimulus
2.the impulse is sent along the sensory neuron to the spinal chord
3.the CNS integrates the information and, if necessary, sends it to the brain for processing prior to initiating a response
4.the impulse is sent from the CNS along the motor neurons to the effector
5.the effector generates the response

Question 4

what do sensory neurons do in the PNS

Answer 4

they conduct impulses from sensory receptors in the skin and other locations

Question 5

what do motor neurons do in the PNS

Answer 5

they cause muscles to contract, and other organs to function. They transmit impulses from the CNS to the muscles and other organs

Question 6

what do the interneurons do in the CNS

Answer 6

transmit impulses between sensory and motor neurons within the brain or spinal chord

Question 7

what do chemoreceptors do

Answer 7

detect the presence of chemicals

Question 8

what do thermoreceptors do

Answer 8

detect changes in the temperature

Question 9

what do mechanoreceptors do

Answer 9

detect mechanical changes in the environment

Question 10

what do photoreceptors do

Answer 10

detect the presence of light

Question 11

auditory receptors (mechanoreceptors)

Answer 11

hair cells in the inner ear vibrate according to the pitch and volume of sounds. they send impulses via the auditory nerve to the brain for processing

Question 12

gustatory receptors (chemoreceptors)

Answer 12

the tongues of many animals are covered with papillae which contain taste buds.

Question 13

visual receptors (photoreceptors)

Answer 13

photoreceptors in the retinal layer of the eye respond to light

Question 14

somatosensory (mechanoreceptors)

Answer 14

skin contains a variety of receptors which respond to temperature, touch or pressure

Question 15

olfactory(chemoreceptors)

Answer 15

receptors in the nasal cavity respond to odour molecules in the air

Question 16

description of the eyelid

Answer 16

fold of skin which covers the eye

Question 17

function of the eyelid

Answer 17

cleaning and protecting the eye

Question 18

description of the cornea

Answer 18

transparent covering on the eye

Question 19

function of the cornea

Answer 19

protecting the eye, helping bend light rays that enter the eye

Question 20

description of the sclera

Answer 20

white part of the eye made of tough collagen fibres

Question 21

function of the sclera

Answer 21

providing protection and support

Question 22

description of the retina

Answer 22

layer of light-sensitive cells at the back of the eye

Question 23

function of the retina

Answer 23

detecting light rays

Question 24

description of the choroid

Answer 24

layer of blood vessels with a black pigment

Question 25

function of the choroid

Answer 25

nourishing the eye and absorbing the light

Question 26

description of the iris

Answer 26

ring of muscles around the pupil, coloured which provides eye colour

Question 27

function of the iris

Answer 27

controls the amount of light entering the eye

Question 28

description of the lens

Answer 28

transparent, flexible and can change shape due to the ciliary muscles

Question 29

function of the lens

Answer 29

focusing the light onto the retina and focuses on objects

Question 30

description of the pupil

Answer 30

hole in the middle of the iris

Question 31

function of the pupil

Answer 31

allowing light to enter the eye

Question 32

description of the ciliary body

Answer 32

attached to the underside of the lens

Question 33

function of the ciliary body

Answer 33

producing aqueous humour and helping with focusing by altering the shape of the lens

Question 34

where is the aqueous humour found

Answer 34

found behind the cornea

Question 35

function of the aqueous humour

Answer 35

helping to keep its rounded shape, providing nutrients to the cornea and lens

Question 36

where is the vitreous humour found

Answer 36

behind the lens

Question 37

function of the vitreous humour

Answer 37

gives the eyeball its shape

Question 38

where is the lateral rectus muscles found

Answer 38

on the lateral side of the eye

Question 39

function of the lateral rectus muscle

Answer 39

helping orientate the pupil away from the centre of the body

Question 40

where is the medial rectus muscle found

Answer 40

on the medial side of the eye

Question 41

function of the medial rectus muscle

Answer 41

helping orientate the pupil towards the centre of the body

Question 42

description of the optic disc

Answer 42

blind spot where there are no photoreceptors

Question 43

function of the optic disc

Answer 43

where the optic nerves leave the eye

Question 44

description of the optic nerve

Answer 44

bundle of fibres

Question 45

function of the optic nerve

Answer 45

relaying information from the retina and fovea to the brain

Question 46

description of the fovea

Answer 46

spot located ion the macula, which has a high density of cone cells

Question 47

function of the fovea

Answer 47

gives sharp central vision, light is focused onto this spot by the lens