Nerves and Sensitivity

Question 1

What are the two organ systems an animal has?

Answer 1

Nervous system, and the endocrine (hormone) system

Question 2

What is the name for plants responding to the environment?

Answer 2

Tropism

Question 3

Define ‘stimulus’

Answer 3

The change in the surroundings

Question 4

Define ‘receptor’

Answer 4

The organ that detects the change in the environment

Question 5

Define ‘effector’

Answer 5

The muscles that respond to the change in the environment

Question 6

What makes the link between the stimulus and the response?

Answer 6

The nervous system

Question 7

What does the eye receptor change into nerve impulses?

Answer 7

Light

Question 8

What does the ear receptor change into nerve impulses?

Answer 8

Sound

Question 9

What does the tongue receptor change into nerve impulses?

Answer 9

Chemical

Question 10

What does the nose receptor change into nerve impulses?

Answer 10

Chemical

Question 11

What does the skin (touch receptors) change into nerve impulses?

Answer 11

Pressure

Question 12

What does the skin (temperature receptors) change into nerve impulses?

Answer 12

Heat

Question 13

What does the central nervous system consist of, and what does it do?

Answer 13

Brain and the spinal cord

Coordinates nervous responses

Question 14

What does the peripheral nervous system consist of?

Answer 14

All the nerves that send impulses to the effectors

Question 15

What are the three types of neurones?

Answer 15

Sensory neurone, relay neurone & motor neurone

Question 16

Which neurone passes impulses from the receptors to the brain and spinal cord (CNS)?

Answer 16

Sensory neurone

Question 17

Which neurone receives impulses from the sensory neurones in the CNS?

Answer 17

Relay neurone

Question 18

Which neurone passes impulses to the effectors from the CNS?

Answer 18

Motor neurone

Question 19

What type of impulses are carried along the neurones, from receptors, to CNS, to effectors?

Answer 19

Electrical signals/impulses

Question 20

Define ‘nucleus’

Answer 20

Contains all the genetic information of a cell

Question 21

Define ‘dendrite’

Answer 21

Tree like projections connecting many different neurones

Question 22

Define ‘cell body’

Answer 22

The main section of the cell, containing the nucleus

Question 23

Define ‘axon’

Answer 23

Carries the electrical impulses

Question 24

Define ‘myelin sheath’

Answer 24

Insulates the axon, and speeds up transmission of impulses

Question 25

Define 'reflexes'

Answer 25

Automated actions not involving the brain, but still involving the three neurones - sensory, relay & motor

Question 26

What is the movement of an impulse between the receptor and the effector?

Answer 26

Reflex arc

Question 27

Describe the reflex arc with this example: you touch a hot surface

Answer 27

1) Receptor (skin - temperature) detects the stimulus change (hot surface), and sends an electrical impulse along the sensory neurone 2) Sensory neurone passes electrical impulse along the spinal cord to a relay neurone, through a synapse, which then passes the electrical impulse to a motor neurone, through a synapse 3) Motor neurone causes the effector (arm muscles) to contract, moving your arm away from the stimulus (hot surface)

Question 28

Describe the reflex arc with this example: a ball is thrown at you

Answer 28

1) Receptor (eye) detects the stimulus change (ball approaching), and sends an electrical impulse along the sensory neurone 2) Sensory neurone passes electrical impulse along the spinal cord to a relay neurone, through a synapse, which then passes the electrical impulse to a motor neurone, through a synapse 3) Motor neurone causes the effector (arm muscles) to contract, moving your arm to catch the stimulus (ball)

Question 29

Define 'synapse'

Answer 29

The gap between the neurones

Question 30

Describe the iris reflex for dim light

Answer 30

1) Receptor (eye) detects the stimulus change (light dimming), and sends an electrical impulse along the sensory neurone 2) Sensory neurone passes electrical impulse along the spinal cord to a relay neurone, through a synapse, which then passes the electrical impulse to a motor neurone, through a synapse 3) Motor neurone causes the effectors (radial muscles and circular muscles in the iris) to contract and relax, respectively, shrinking your iris to allow more light into your eye

Question 31

Describe the iris reflex for bright light

Answer 31

1) Receptor (eye) detects the stimulus change (light brightening), and sends an electrical impulse along the sensory neurone 2) Sensory neurone passes electrical impulse along the spinal cord to a relay neurone, through a synapse, which then passes the electrical impulse to a motor neurone, through a synapse 3) Motor neurone causes the effectors (radial muscles and circular muscles in the iris) to relax and contract, respectively, enlarging your iris to allow less light into your eye

Question 32

Define 'cornea'

Answer 32

The curved disk in front of your eye, which does most of the focusing

Question 33

Define 'pupil'

Answer 33

A circular opening, whose size is controlled by the iris

Question 34

Define 'iris'

Answer 34

A ring of muscles circling the pupil, controlling the amount of light entering the eye

Question 35

Define 'lens'

Answer 35

A soft, flexible & transparent layer that fine tunes the focusing of light onto the retina

Question 36

Define 'ciliary muscles'

Answer 36

A ring of muscles circling the iris, which control the thickness of the lens - when it contracts, the lens gets fatter, when it relaxes, the lens gets thinner

Question 37

Define 'suspensory ligaments'

Answer 37

Strong fibres attaching the lens to the ciliary muscles

Question 38

Define 'retina'

Answer 38

Contains light sensitive cells called rods and cones, and is where images are displayed (upside down)

Question 39

Define 'optic nerve'

Answer 39

Consists of many neurones, which carry impulses from the retina to the brain

Question 40

Define 'fovea'

Answer 40

The region of the retina with the greatest number of cones

Question 41

Define 'conjunctive'

Answer 41

A mucous membrane covering the eye, to prevent infection