Nervous System

Question 1

BIOLOGY ONLY - The Eye - What is the function of the retina?

Answer 1

• Retina - conatins light receptors (rod and cone cells)
• Detects the light and sends electrical impulses to the brain.

Question 2

How do nerve impulses travel across synapses?

Answer 2

Chemical messengers

Question 3

What is the difference between and reflex action and a reflex arc?

Answer 3

Reflex action follows this general sequence and does not involve the conscious part of the brain, which makes it much quicker. The nerve pathway followed by a reflex action is called a reflex arc.

Question 4

BIOLOGY ONLY - The Eye - What is the function of the sclera?

Answer 4

Sclera - tough, opaque outer layer of the eye which protects the eye from injury.

Question 5

BIOLOGY ONLY - The Eye - How can myopia (short sightedness) be corrected?

Answer 5

Using concave lens - which bends the light rays outwards so that they are focused on the retina.

Question 6

BIOLOGY ONLY - The Eye - What is myopia?

Answer 6

Myopia (SHORTer word) is SHORT sightedness

Question 7

BIOLOGY ONLY - The Eye - Which new technologies can be used to correct eye defects?

Answer 7

• Contact lenses (Hard and soft)
• Laser surgery to change the shape of the cornea
• Replacement lens in the eye.

Question 8

BIOLOGY ONLY - The Eye - Describe what happens to eye in bright light

Answer 8

• Circular muscles: Contract to close the pupil
• Radial muscles: Relax
• Iris: Gets bigger
• Pupil: Contracts (gets smaller)

Question 9

BIOLOGY ONLY - Identify the different parts of the brain

Answer 9

A) Cerebral cortex B) cerebellum C) medulla (D = Hypothalamus)

Question 10

How does the structure of a motor neurone relate to its function?

Answer 10

• Structure: Have a myelin sheath for faster transmission; packed with mitochondria
• Function: Carry electrical impulses away from the CNS to effectors

Question 11

What is a myelin Sheath

Answer 11

This insulates or protects neurones

Question 12

BIOLOGY ONLY - What is the function of the brain?

Answer 12

The brain controls complex behaviour. It is made of billions of interconnected neurones and has different regions that carry out different functions.

Question 13

What is a receptor? Give examples

Answer 13

• A receptor is a sensory cell which detects changes in the environment (stimuli) and passes this information to attached sensory neurones.
• Examples include rod and cone cells in the retina of the eye and temperature / pressure or pain receptors in the skin.

Question 14

What is the CNS?

Answer 14

• The Central nervous system (CNS).
• The CNS is the brain and spinal cord

Question 15

How do nerve impulses travel across synapses?

Answer 15

Chemical messengers (called neurotransmitters) diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the second neurone.

Question 16

BIOLOGY ONLY - The Eye - What is the function of the iris?

Answer 16

Iris - controls the amount of light that enters the eye.

Question 17

List the sequence of events in a reflex

Answer 17

stimulus > receptor > coordinator > effector > response

Question 18

BIOLOGY ONLY - The Eye - What is hyperopia?

Answer 18

Hyperopia (LONGer word) is LONG sightedness

Question 19

BIOLOGY ONLY - The Eye - What is the function of the ciliary muscles?

Answer 19

Ciliary muscles - attaches the ciliary muscle to the eye and helps to change the shape of the lens.

Question 20

BIOLOGY ONLY - The Brain - What is the function of the cerebellum?

Answer 20

cerebellum - controls balance, co-ordination of movement and muscular activity.

Question 21

BIOLOGY ONLY - The Eye - Identify structures in the eye

Answer 21

Question 22

• What is an effector? Give examples

Answer 22

• An effector is linked to a motor neurone and causes a response.
• Examples: muscles contracting or glands secreting hormones.

Question 23

BIOLOGY ONLY - The Eye - Describe what happens to eye in dim light

Answer 23

• Circular muscles: Relax
• Radial muscles: Contract to open the pupil
• Iris: Gets smaller
• Pupil: Relaxes (opens)

Question 24

Exam Question: Features of neurones

Answer 24

Question 25

Give 3 features of reflex actions

Answer 25

* Automatic * Rapid * Do not involve the conscious part of the brain.

Question 26

* How does the structure of a relay neurone relate to its function?

Answer 26

* Structure: no myelin sheath so slower transmission * Only found in the spinal cord and brain. * Function: Carry electrical impulses from sensory to motor neurones

Question 27

BIOLOGY ONLY - The Brain - What is the function of the medulla?

Answer 27

medulla - controls unconscious activities such as heart rate and breathing rate

Question 28

BIOLOGY ONLY - The Eye - What is accommodation?

Answer 28

The process of changing the shape of the lens to focus on near or distant objects.

Question 29

BIOLOGY ONLY - The Eye - What is the function of the suspensory ligaments?

Answer 29

Suspensory ligaments - attaches the ciliary muscle to the eye and helps to change the shape of the lens.

Question 30

BIOLOGY HIGHER ONLY - The Brain - What are the difficulties of investigating brain function and treating brain damage and disease?

Answer 30

The complexity and delicacy of the brain makes investigating and treating brain disorders very difficult.

Question 31

What is the function of the nervous system?

Answer 31

Enables humans to react to their surroundings and to coordinate their behaviour.

Question 32

BIOLOGY ONLY - The Eye - What is the function of the cornea?

Answer 32

Cornea - transparent front part of the eye which focuses the light by a fixed amount

Question 33

BIOLOGY ONLY - The Eye - How does the eye focus on a near object?

Answer 33

• the ciliary muscles contract • the suspensory ligaments loosen • the lens is then thicker (fatter) and refracts (bends) light rays strongly.

Question 34

BIOLOGY ONLY - Exam Question: Brain Function

Answer 34

Question 35

How does the structure of a sensory neurone relate to its function?

Answer 35

* Structure: Have a myelin sheath for faster transmission; packed with mitochondria * Function: Carry electrical impulses to the CNS from receptors

Question 36

BIOLOGY ONLY - The Eye - What is the function of the optic nerve?

Answer 36

Optic nerve - carries electrical impulse from the retina to the brain.

Question 37

What is the function of the CNS?

Answer 37

To coordinate the response of effectors which may be muscles contracting or glands secreting hormones.

Question 38

What is a synapse?

Answer 38

A gap / junction / connection between neurones.

Question 39

Why does the pupil get smaller in bright light?

Answer 39

To prevent damage to the retina

Question 40

BIOLOGY ONLY - The Brain - What is the function of the cerebral cortex?

Answer 40

cerebral cortex - controls intelligence, personality, conscious thought and high-level functions, such as language and verbal memory.

Question 41

What is a stimulus?

Answer 41

A change in the environment.

Question 42

BIOLOGY ONLY - The Eye - How can hyperopia (long sightedness) be corrected?

Answer 42

Using convex lens - which bends the light rays inwards so that they are focused on the retina.

Question 43

BIOLOGY HIGHER ONLY - The Brain - How have neuroscientists been able to map the regions of the brain to particular functions?

Answer 43

By studying patients with brain damage, electrically stimulating different parts of the brain and using MRI scanning techniques.

Question 44

BIOLOGY ONLY - The Eye - What is the eye's function?

Answer 44

A sense organ containing receptors sensitive to light intensity and colour.