4.5 Response and regulation

Question 1

What stimulus does the Eye receive?

Answer 1

Light

Question 2

What stimulus does the Ear reveice?

Answer 2

Sound

Question 3

What stimulus does the Nose reveive?

Answer 3

Chemical smells

Question 4

What stimulus does the Tongue receive?

Answer 4

Chemical tastes

Question 5

What stimulus does skin reveive?

Answer 5

Pain, pressure, temperature

Question 6

What are the three properties of a reflex response?

Answer 6

• Rapid
• Automatic
• Protective

Question 7

What are the five components of the reflex arc in order?

Answer 7

• Receptor (skin)
• Sensory neurone
• Relay neurone
• Motor neurone
• Effector muscle

It is also worthy of note that the spinal cord co-ordinates the reflex, and the relay neurone is located within it.

Question 8

What is a negative feedback loop?

Answer 8

Any change from the balance in optimal internal conditions results in the body’s hormonal and nervous systems compensating for the change and restoring the balance.

Question 9

What is a positive feedback loop?

Answer 9

Any change from the balance in optimal internal conditions results in the body’s hormonal and nervous systems amplifying the change, until the balance is restored by another factor (e.g in childbirth).

Question 10

Define Homeostasis.

Answer 10

Homeostasis is the maintenance of a constant internal environment.

Question 11

What is the function of the Iris?

Answer 11

The Iris relaxes and contracts to control the amount of light entering the eye and hitting the Retina.

Question 12

What is the function of the Retina?

Answer 12

The Retina is a light sensitive layer that forms an image (like a camera sensor) and sends the signals to the brain for processing via the optic nerve.

Question 13

What is the function of the Sclera and Cornea in the eye?

Answer 13

The Sclera is a tough, protective white outer coat. The Cornea is a clear part of the Sclera that allows light into the eye.

Question 14

What is the function of the Lens?

Answer 14

The lens (like a camera lens), changes shape to focus light onto the Retina. It directs the light entering, directly onto the Retina.

Question 15

What is the cause of Type I Diabetes?

Answer 15

Type I Diabetes is caused by genetics.

Question 16

What is the cause of Type II Diabetes?

Answer 16

Type II Diabetes is caused by too much daily sugar intake over a prolonged period of time.

NOTE: This is an accepted WJEC response. In reality, the cause of Type II Diabetes is more general, and can be caused by any form of bad diet, including but not limited to high sugar intake.

Question 17

What is the functional difference between Type I and Type II Diabetes?

Answer 17

In Type I Diabetes the body does not release insulin, whereas in Type II Diabetes, the body cells do not respond to the chemical signal from insulin.

Question 18

How can you detect Diabetes?

Answer 18

Glucose in urine detected by a Benedict’s test.

Question 19

What are the treatments of Type II Diabetes?

Answer 19

• Injecting insulin
• Pancreas transplants
• Low sugar/ carbohydrates diet

Question 20

How does Human Skin regulate Temperature when the skin is too hot?

Answer 20

• Hairs lie flat
• Sweating
• Vasodilation

Question 21

How does Human Skin regulate Temperature when the skin is too cold?

Answer 21

• Hairs stand on end
• Shivering
• Vasoconstriction

Question 22

How are Hairs controlled on Human Skin?

Answer 22

Hairs are controlled using the Hair Erector Muscle.

Question 23

What is the function of raising and lowering Hairs on Human Skin?

Answer 23

Raising hairs traps a layer of insulating air over the skin, reducing heat loss.

Question 24

How do Humans Sweat?

Answer 24

The Sweat Gland produces sweat, which is then forced up the Sweat Duct, and released out the Sweat Pore onto the surface of the skin.

Question 25

What is the function of Sweating?

Answer 25

Sweating allows heat to be transferred into the sweat, expelled from the skin, then evaporated, taking the heat with it.

Question 26

What is Vasodilation and Vasoconstriction?

Answer 26

Vasodilation is where blood vellels relax, allowing blood to flow to the surface of the skin, expelling heat via the skin, and thus cooling the blood, whereas Vasoconstriction contracts the blood vessels, keeping the blood as close to the core as possible, retaining heat.