coordination and response and the eye

Question 1

how does the nervous system work

Answer 1

a receptor receives a stimuli, which then sends a message to the control centre which then in turn sends a message to an effector

Question 2

what are types of receptors

Answer 2

thermoreceptors, auditory receptors, olfactory receptors, photoreceptors, peripheral chemoreceptors(chemical changes in the blood) and nociceptors(detecting and responding to pain), baroreceptors(pressure)

Question 3

what are examples of effectors

Answer 3

muscles and glands

Question 4

what sense organ contains photoreceptors

Answer 4

eyes light is its stimulus and the function of it is sight

Question 5

what sense organ contains baroreceptors

Answer 5

ears its stimulus is air vibrations and its function is to hear

Question 6

what sense organ contains chemoreceptors

Answer 6

nose its stimulus being chemicals and its function being to smell

Question 7

what sense organ contains chemoreceptors

Answer 7

tongue its stimulus being chemicals and its function being to taste

Question 8

what sense organ contain thermoreceptors and mechanoreceptors

Answer 8

skin its stimulus being heat pressure and its function being to touch

Question 9

what is the function of a sensory neurone

Answer 9

transporting the message from the stimulus to the CNS

Question 10

what is the function of a relay neurone

Answer 10

In CNS

Message from sensory neurone passed to motor neurone

Question 11

what is the function of a motor neurone

Answer 11

Comes from CNS

Message ends with EFFECTOR

Question 12

what is a synapse

Answer 12

Where the electrical impulse passes from one neurone to the next

Question 13

what is the iris

Answer 13

the coloured part of the eye which can expand and contract to control the amount of light that enters the eye.

Question 14

what is the ciliary muscle

Answer 14

changes the shape of the lens for focusing

Question 15

what is the pupil

Answer 15

the circular opening which lets light into the eye. It appears black because the choroid is visible through it.

Question 16

what is the cornea

Answer 16

a transparent layer responsible for most of the refraction (bending) of light rays that enter the eye.

Question 17

what is the retina

Answer 17

contains the light-sensitive cells, the rods and cones.

Question 18

what is the yellow spot

Answer 18

this area has the highest density of cones and thus offers maximum sharpness but only works at full efficiency in bright light.

Question 19

what is the vitreous humor

Answer 19

a jelly-like substance which helps to keep the shape of the eyeball, supports the lens and keeps the retina in place at the back of the eye.

Question 20

what is the aqueous humor

Answer 20

watery fluid which supports the cornea and the front chamber of the eye.

Question 21

what is the suspension ligament

Answer 21

attaches ciliary muscles to the lens

Question 22

what is the function of the lens

Answer 22

helps to focus

Question 23

what is the chloroid

Answer 23

a darkly coloured layer which reduces reflections inside the eye and contains blood vessels which help to nourish the cells of the retina.

Question 24

what is the sclera

Answer 24

the tough outer coat which protects the eye against damage. The muscles that move the eye in its socket attach to the sclera.

Question 25

what is the optic nerve

Answer 25

composed of sensory neurones which carry nerve impulses to the visual centre at the rear of the brain.

Question 26

what is the blind spot

Answer 26

at the exit point of the optic nerve. There are no light-sensitive cells here so light falling on this region cannot be detected.

Question 27

what is a rod light receptor

Answer 27

Sensitive to low light intensities – enable us to see in black and white

Question 28

what is a cone light receptor

Answer 28

Sensitive to high light intensities– enable us to see in colour