nervous system

Question 1

What do we call cells which detect stimuli?

Answer 1

Receptors

Question 2

What are stimuli?

Answer 2

Changes in the environment which trigger the nervous response

Question 3

What are individual nerve cells called?

Answer 3

Neurones

Question 4

What is an effector?

Answer 4

A muscle or gland which carries out a response

Question 5

Which type of signal is used in the nervous system?

Answer 5

Electrical impulses

Question 6

What is the central nervous system?

Answer 6

Brain and spinal cord

Question 7

What is the peripheral nervous system?

Answer 7

all the nerves which are not in the brain and spinal cord

Question 8

Why do neurones have a myelin sheath?

Answer 8

to insulate the neurone, meaning impulses travel faster

Question 9

Where do sensory neurones carry impulses?

Answer 9

from a receptor to the central nervous system

Question 10

Where do motor neurones carry impulses?

Answer 10

from the central nervous system to an effector

Question 11

What is the route an impulse takes within the nervous system?

Answer 11

(stimulus) > receptor > sensory neurone > brain > motor neurone > effector > (response)

Question 12

What is a synapse?

Answer 12

A gap between two neurones

Question 13

What is released from a nerve-ending when an impulse reaches a synapse?

Answer 13

neurotransmitters (chemicals)

Question 14

How to neurotransmitters travel across a synapse?

Answer 14

diffusion

Question 15

What happens when a neurotransmitter has travelled across a synapse?

Answer 15

it binds to the cell membrane on the second neurone, triggering an electrical impulse

Question 16

What is a reflex action?

Answer 16

an automatic response that does not require thought (e.g. moving a hand away from a hot object)

Question 17

Why are reflexes important to the body?

Answer 17

They are faster than the usual nervous response, minimising damage to the body

Question 18

What is the difference between a reflex and the normal nervous response?

Answer 18

Reflex is faster. In a reflex arc the impulse does not always travel to the brain, it travels to the closest relay neurone in the central nervous system

Question 19

Where are relay neurones found?

Answer 19

central nervous system

Question 20

What are the stages in the reflex arc?

Answer 20

stimulus > receptor> sensory neurone > relay neurone > motor neurone > effector > response

Question 21

What is the function of the cerebellum?

Answer 21

part of the brain that controls balance and coordination

Question 22

What is the function of the medulla?

Answer 22

part of the brain that controls vital functions such as breathing, heart rate and digestion

Question 23

What is the function of the cerebral cortext?

Answer 23

part of the brain responsible for sense, intelligence, personality, conscious thought, language and memory

Question 24

What is the function of the hypothalamus?

Answer 24

part of the brain that regulates temperature and water balance within the body

Question 25

How can brain function be investigated by scientists?

Answer 25

Using a CT scan or PET scanning

Question 26

What happens during a CT scan?

Answer 26

patient passes through a ring of equipment which takes x-rays from different angles

Question 27

What happens during a PET scan?

Answer 27

Specialist equipment detects gamma rays from a tracer which is eaten by the patient before the scan. The tracer travels to a part of the body where there is a cancer

Question 28

What is the function of the cornea?

Answer 28

part of the eye which refracts light entering the eye

Question 29

What is the function of the iris?

Answer 29

Controls how much light enters the pupil

Question 30

What is the function of the lens in the eye?

Answer 30

refracts light to focus it onto the retina

Question 31

What is the function of the optic nerve?

Answer 31

carries impulses from the eye to the brain

Question 32

What is the function of the sclera?

Answer 32

tough outer layer of the eye which protects it from injury

Question 33

What is the function of the retina?

Answer 33

contains light receptors

Question 34

Which two types of receptors are in the retina?

Answer 34

Rods and cones

Question 35

What is the difference between rods and cones?

Answer 35

rods are more sensitive to light so are used for seeing in dimmer light. There are different types of cones which allow us to see in colour

Question 36

What is short-sightedness?

Answer 36

When a person can see near objects clearly but cannot focus on distant objects.

Question 37

What causes short-sightedness?

Answer 37

The eye is too long or the lens is too thick and curved. The light is focused in front of the retina

Question 38

How is short-sightedness corrected?

Answer 38

Using a concave lens

Question 39

What is long-sightedness?

Answer 39

When a person can see distant objects clearly but cannot focus on close up objects

Question 40

What causes long-sightedness?

Answer 40

The eye is too short or the lens is too thin. The light is focused behind the retina

Question 41

How is long-sightedness corrected?

Answer 41

Using a convex lens

Question 42

What is a cataract?

Answer 42

Cloudiness in the lens caused by a build up of protein inside the lens

Question 43

How is cataracts treated?

Answer 43

Using surgery to remove the lens and replace it with a plastic lens

Question 44

What is colourblindness?

Answer 44

When a person is missing one or more types of cone, meaning they are unable to distinguish between certain colours (depending on the cone missing)