Topic 5-Homeostasis And Responce

Question 1

What system is the brain part of?

Answer 1

The Central Nervous system.

Along with the spinal cord

Question 2

Made up of billions of interconnected neurones

In charge of all complex behaviour

Controls and coordinates everything you do.

Answer 2

E.g Breathing, running and sleeping

Question 3

What are the regions of the the brain?

Answer 3

The cerebral cortex
The medulla
The cerebellum

Question 4

What is the Cerebral Cortex?

Answer 4

• the outer ‘wrinkled’ layer of the brain

- responsible for intelligence, language, memory and consciousness

Question 5

What is the Medulla?

Answer 5

-lower part of the brain stem
(Base of brain, at the top of the spinal cord)

-responsible for involuntary coordination.
E.g breathing, swallowing

Question 6

What is the Cerebellum?

Answer 6

• lower part of the back of the brain

- responsible for voluntary coordination of the muscles

Question 7

What are the different methods to study how the brain works?

Answer 7

• studying patients with brain damage
• electrically stimulating the brain

-magnetic resonance imaging scans
(MRI scan)

Question 8

Explain the method of studying patients with brain damage.

Answer 8

-if a small part of the brain has been damaged, the effect this has on the patient can tell you a lot about the damaged part of the brain does.

Question 9

Explain the method of electrically stimulating the brain.

Answer 9

• Stimulated electrically by punching a tiny electrode into the tissue and giving it a small zap of electricity
• when stimulated it shows what different parts of the brain does

E.g certain parts of brain muscle contract and move when stimulated

Question 10

Explain MRI scan.

Answer 10

-scientists use it to find out what areas of the brain are active when people are doing things like listening to music or trying to recall a memory.

Question 11

What is the benefits and risk of studying the brain?

Answer 11

• electrical stimulation can reduce muscle tremors
• surgery to remove a part of the brain that’s causes seizures can treat epilepsy

-can cause physical damage or increased problems with brain function
(E.g Difficulties with speech)

Question 12

What are the parts of the eye?

Answer 12

• sclera
• cornea
• pupil
• iris
• retina
• lens
• ciliary muscles and suspensory ligaments
• optic nerve

Question 13

What is the sclera?

Answer 13

• tough, supporting wall of the eye

- protects and holds eye in place

Question 14

What is the cornea?

Answer 14

• transparent outer layer found at front of eye

- refracts light into the eye

Question 15

What is the pupil?

Answer 15

• hole in centre of the eye

- through which light enters

Question 16

What is the iris?

Answer 16

• contains muscles that control the diameter of pupil

- regulates the amount of light reaching the retina

Question 17

What is the retina?

Answer 17

• layer at the back of eye
• contains two types of light receptors
• one is sensitive to light intensity
• other is sensitive to colour

-contains rods and cone cells

Question 18

What is the lens?

Answer 18

-focuses light into the retinas

Question 19

What is the ciliary muscles and suspensory ligaments?

Answer 19

-control the shape of the lens to focus light rays on the retina

Question 20

What is the optic nerve?

Answer 20

-carries impulses from the receptors on the retina to the brain

Question 21

What is accommodation?

Answer 21

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

Question 22

What happens when you try and focus on a distant object?

Answer 22

1. Ciliary muscles relax
2. Suspensory ligaments pull tight
3. Makes Lens pull thin (less curved)
4. So refracts light by a smaller amount

Question 23

What happens when you focus on a near object?

Answer 23

1. Ciliary muscles contact
2. Suspensory ligaments loosen
3. Makes lens go thicker (more curved)
4. The amount of light refracted increases

Question 24

What is long-sightedness called?

Answer 24

Hyperopia

Question 25

What is short-sightedness called?

Answer 25

Myopia

Question 26

Explain myopia.

Answer 26

• can’t focus on objects that are far away
• usually occurs when the eyeball is too long
• light rays from distant objects focus in the eyeball in front of the retina
• can be corrected by concave lenses (curved inwards) so that the light rays can focus on the retina

Question 27

Explain Hyperopia

Answer 27

• can’t focus on objects that are near
• usually occurs when the eyeball is too short
• light rays from distant objects focus in the eyeball behind the retina
• can be corrected by convex lenses (curved outwards) so that the light rays can focus on the retina

Question 28

What are alternate treatments for myopia and hyperopia?

Answer 28

• contact lenses
• laser eye surgery
• replacement lens surgery

Question 29

Explain contact lens.

Answer 29

• thin lenses on surface of eye
• shaped to compensate for fault in focusing
• lightweight and almost invisible and more convenient for sports
• two types soft lenses and hard lenses
• soft are more comfortable but has higher risk of eye infections

Question 30

Explain laser eye surgery.

Answer 30

-vaporises tissue, changing the shape of the cornea
(changing how strongly it refracts light into eye)

• slimming it down to make less powerful to improve short sight
• changing shape to make more powerful to improve long sight
• risk of complications such as infection or eye reacting in a way making vision worse

Question 31

Explain lens surgery.

Answer 31

• good for long-sightedness
• natural lens is removed and artificial lens made of plastic is inserted in its place

-higher risk of laser eye surgery
-could damage retina
(which could lead to loss of sight)