B10- The Human Nervous System

Question 1

What is homeostasis?

Answer 1

The regulation of the internal conditions of cells to maintain optimum conditions for functioning, in response to internal and external changes.

Question 2

Why is homeostasis important?

Answer 2

For maintaining optimal conditions for enzyme action,

Question 3

What internal conditions are controlled?

Answer 3

Body temp
Water content of the body
Blood glucose concentration 
Salts
pH
Ions

Question 4

What is automatic control?

Answer 4

Involves nervous responses in your nervous system and chemical responses in your hormone system.

Question 5

What are receptors?

Answer 5

Cells that detect changes in internal or external environment.

Question 6

What are coordination centres?

Answer 6

Receives info from receptors, process the info and coordinate responses in the body.

Question 7

What are effectors?

Answer 7

Muscles or glands that bring about responses to the stimulus that has been received

Question 8

What does the nervous system do?

Answer 8

Send electrical impulses to enable you to react quickly to your surroundings and coordinate your behaviour

Question 9

What do receptors detect?

Answer 9

Stimuli (changes in the environment)

Question 10

How does the nervous system work?

Answer 10

Impulses from receptors pass along sensory neurones to the brain or spinal cord. The brain then coordinates the response and impulses are sent along motor neurones from the brain to the effector organs.

Question 11

What are reflex actions?

Answer 11

These are automatic and rapid and do not involve the consciousness or the brain.

Question 12

What is the route of reflex actions?

Answer 12

Receptors
Sensory neurone
Spinal cord
Motor neurone 
Effector

Question 13

What do reflex actions control?

Answer 13

Everyday bodily functions eg breathing and digesting and help to avoid danger.

Question 14

What is the brain made up of?

Answer 14

Billions of interconnected neurones that control complex behaviours.

Question 15

What is the cerebral cortex?

Answer 15

Concerned with consciousness, intelligence, memory and language

Question 16

What is the cerebellum?

Answer 16

Concerned with coordinating muscular activity and balance.

Question 17

What is the medulla?

Answer 17

Concerned with unconscious activities such as controlling the heartbeat, the movements of the gut and breathing

Question 18

What is electrically stimulating the brain?

Answer 18

Removing the top of the skull, scientists can stimulate different areas and see what effect this has. You could experience hunger, anger or fear by stimulating the brain.

Question 19

What are MRI scans?

Answer 19

You can understand how the brain works by taking photos of the brain. If there is a tumour an MRI can show exactly which area of the brain is affected.

Question 20

What are problems with the brain?

Answer 20

It is difficult to treat different brain problems. Drugs may not reach the brain through the membrane and surgery is difficult as we do not know fully what each area of the brain does.

Question 21

What is accommodation?

Answer 21

Changing the lens shape to focus on near or distant objects.

Question 22

To focus on near object:

Answer 22

The ciliary muscles contract.
Radial muscles relax.
Pupils constricts.

Question 23

To focus on near objects:

Answer 23

Ciliary muscles relax
Radial muscles contract
Pupils dilate

Question 24

What are the use of contact lenses?

Answer 24

Placed on the surface of the eye and are the same as glasses but are less visible and easier to use.

Question 25

What is laser eye surgery?

Answer 25

Lasers treat myopia by reducing the thickness of the cornea so refracts less light. Hyperopia lasers change the curve of the cornea.

Question 26

What are replacement lenses?

Answer 26

Add another lens inside the eye to correct the visual defect permanently.