Nervous system

Question 1

What does the nervous system do?

Answer 1

It uses signalling molecules to communicate messages around the body and tells parts of your body what to do.

Question 2

What are the two parts of the nervous system?

Answer 2

The Central Nervous System (CNS) which is the brain and spinal cord. The Peripheral Nervous System (PNS) which consists of neurons connecting the CNS to the rest of the body.

Question 3

Explain the stimulus response mechanism.

Answer 3

Changes are detected by special cells called receptors. Receptors receive information, or stimulus that will result in a particular response from the body.

Question 4

What are the 5 stages of the stimulus response mechanism?

Answer 4

Stimulus - Receptor - Control Centre - Effector - Response

Question 5

What are the five different types of receptors and their respective locations and stimulus?

Answer 5

Thermoreceptor - temperature - Skin
Mechanoreceptor - vibration(sound)/touch/pressure - Ear, Skin
Chemoreceptor - chemicals - Nose, Tongue
Photoreceptor - light - Eyes
Nociceptor - damage to cells (pain) - Skin

Question 6

What is the name of the cells that make up the nervous system?

Answer 6

Neurons

Question 7

What are the three main parts of neurons?

Answer 7

Dendrites - receive info from receptors or other neurons
Cell body - contains nucleus and provides energy for cell
Axon - Conducts impulse from dendrites to axon terminals

Question 8

True or false an impulse only ever travels one way?

Answer 8

True

Question 9

What are the three types of neurons?

Answer 9

Sensory neurons - carry the impulse generated by the stimulus to the CNS
Interneurons - carry the impulse through the CNS
Motor neurons - take the impulse to effectors such as muscles or glands

Question 10

What is the function of neurons?

Answer 10

They send messages from where the information is received to the part of the body that will respond to that information.

Question 11

What is the name of the small gap between neurons and how does information cross it?

Answer 11

The synapse and it is crossed using a special chemical called a neurotransmitter.

Question 12

What happens when an impulse reaches an axon terminal?

Answer 12

Neurotransmitters are released.

Question 13

What is a reflex arc?

Answer 13

A special pathway in the nervous system that results in a reflex action that occurs so rapidly it requires no conscious thought. This occurs to protect the body from harm.

Question 14

What is the iris?

Answer 14

The iris is the coloured part of the eye which surrounds the pupil. The iris will change size to change the amount of light that passes through the pupil.

Question 15

What is the cornea?

Answer 15

The layer that covers the front of the eye.

Question 16

What is the lens?

Answer 16

The lens sits behind the pupil and focusses light on the retina. The eye has light receptors which detect light found in the retina.

Question 17

What are the two types of photoreceptors and their functions?

Answer 17

Rods - detect light levels
Cones - detect colour

Question 18

What is the nerve that travels form the eye to the brain?

Answer 18

The optic nerve.

Question 19

What is the pupillary light effect?

Answer 19

When light shines into the eyes the receptors will send a message to the brain as well as trigger a response to change the size of the pupil to regulate the amount of light passing through to protect the eye.

Question 20

What are the three parts of the ear?

Answer 20

The outer ear - Pinna(external part of the ear), canal, and ear drum
The middle ear - Ossicles(3 tiny bones)
The inner ear - Cochlea which connects to the auditory nerve

Question 21

What is the process of hearing sound?

Answer 21

When air inside your ear vibrates it causes the ear drum to vibrate. The ossicles receive this information and pass it to the inner ear. Hairs attached to the nerve cells of the cochlea detect the vibration and an impulse is sent to the brain through the auditory nerve.