B10 - The Human Nervous System

Question 1

Define homeostasis

Answer 1

The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes.

Question 2

Internal conditions that are controlled include?

Answer 2

Body temperature
The water content of the body
Blood glucose concentration

Question 3

Define receptors

Answer 3

Cells that detect changes in the internal and external environment.

Question 4

Define stimuli

Answer 4

Changes in the internal or external environment.

Question 5

Define coordination center

Answer 5

Areas that receive and process the information from the receptors. They send out signals and coordinate the response of the body.

Question 6

What do coordination centres include?

Answer 6

The brain, the spinal cord, and some organs such as the pancreas

Question 7

Define effectors

Answer 7

Muscles or glands that bring about responses to the stimulus that has been received. These responses restore conditions in the body to the optimum levels.

Question 8

Define neurones

Answer 8

Special cells that pass an electrical impulse sent from a sensory receptor when it detects a stimulus.

Question 9

Where are neurones found?

Answer 9

They are found in bundles of hundreds or even thousands of neurones known as nerves.

Question 10

What do impulses travel along neurones to?

Answer 10

The central nervous system (CNS)

Question 11

What is the central nervous system (CNS) made up of?

Answer 11

The CNS is made up of the brain and the spinal cord.

Question 12

Define sensory neurones

Answer 12

The cells that carry impulses from your sense organs to your central nervous system (CNS).

Question 13

Define motor neurones

Answer 13

Motor neurones carry impulses from the central nervous system (CNS) to the effector organs.

Question 14

What order do things happen in the nervous system?

Answer 14

Stimulus 》receptors 》coordinators (CNS) 》effector

Question 15

Define reflex

Answer 15

An automatic responses like blinking, pulling your hand back, etc…

Question 16

What are the three types of neurones?

Answer 16

Sensory neurones
Motor neurones
Relay neurones

Question 17

Define relay neurones

Answer 17

Connect sensory neurone and a mother neurone, and are found in the (CNS)

Question 18

What is the pathway of a reflex arc?

Answer 18

Stimulus 》receptor 》sensory neurone 》relay neurone 》motor neurone 》effector 》response

Question 19

Define meninges

Answer 19

The protective membrane that encases the brain.

Question 20

What is the cerebral cortex in control of?

Answer 20

Consciousness, intelligence, memory and language.

Question 21

What is the cerebellum in control of?

Answer 21

Coordinating muscular activity and balance.

Question 22

What is the medulla in control of?

Answer 22

Unconscious activities such as controlling the heartbeat, the movements of the gut, and breathing.

Question 23

What is the light-sensitive layer in the back of the eye called?

Answer 23

Retina

Question 24

What happens to the eye when the light is bright?

Answer 24

The circular muscles contract, radial muscles relax, and the pupils constrict.

Question 25

What happens to the eye when the light is dim?

Answer 25

Circular muscles relax, radial muscles contract, and the pupils dilate.

Question 26

What changes the shape of the lens to fine focus light on to the retina?

Answer 26

The ciliary muscles and suspensory ligaments.

Question 27

What does the optic nerve do?

Answer 27

The optic nerve carries impulses from the retina to the brain.

Question 28

What is the sclera?

Answer 28

The sclera is a tough outer layer that has a transparent region at the front called the cornea that let’s light in that refracts (changes the direction of) light towards the retina.

Question 29

Define myopia

Answer 29

Short sightedness

Question 30

Define hyperopia

Answer 30

Long sightedness

Question 31

Define accommodation in terms of the eye

Answer 31

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

Question 32

What happens to the eyes when they need to focus on close objects?

Answer 32

To focus on close objects, the ciliary muscles contract, the suspensory ligaments loosen, and the lens becomes thicker so it can reflect light rays strongly.

Question 33

What happens to the eyes when they need to focus on distant objects?

Answer 33

To focus on distant objects, the ciliary muscles relax, the suspensory ligaments are pulled tight, and the lens becomes thiner so it can reflect light rays slightly.

Question 34

How can sight defects be treated?

Answer 34

Spectacle lenses, hard and soft contact lenses, laser surgery, and replacement lenses in the eye.