Homeostasis

Question 1

What is homeostasis?

Answer 1

A self regulating process, by which a living organism can maintain internal stability while adjusting to changes in external conditions.

Question 2

Why does your body temperature need to be controlled?

Answer 2

To prevent hypothermia, overheating and your cells from denaturing.

Question 3

Why does your blood PH need to be controlled?

Answer 3

If it is too low or too high your cells will denature.

Question 4

Why do your blood glucose levels need to be controlled?

Answer 4

To avoid:
- Hyperglycaemia (Your body’s blood glucose
levels are higher than the standard range).
- Hypoglycaemia (Your body’s blood glucose
levels are lower than the standard range).

Question 5

Why does your water potential need to be controlled?

Answer 5

So you don’t get dehydrated and so your cells don’t swell.

Question 6

What is a negative feedback loop?

Answer 6

A normal biological response in which the effects of a reaction slow or stop that reaction. It regulates.

Question 7

What is a positive feedback loop?

Answer 7

This is when the product of a reaction leads to an increase in that reaction. It does not regulate.

Question 8

What is an example of a positive feedback loop?

Answer 8

During labour a hormone called oxytocin is released, causing stronger contractions. These stronger reactions stimulate the release of more oxytocin. This cycle continues till birth.

Question 9

What is thermoregulation?

Answer 9

A process which occurs when you are too hot or too cold.

Question 10

What happens when you are too hot?

Answer 10

• Your blood vessels dilate to release heat.
• Sweat is produced and heat leaves via evaporation.
• Your heart rate increases to circulate blood faster.

Question 11

What happens when you are too cold?

Answer 11

• You shiver to generate heat.
• Your blood vessels constrict to reduce heat loss.
• Your metabolism increases to produce more heat.

Question 12

What is vasoconstriction?

Answer 12

When your blood vessels narrow, to reduce blood flow to regulate your temperature.

This reduces heat loss.

Question 13

What is vasodilation?

Answer 13

When your blood vessels widen, to allow more blood to flow through, increasing blood flow.

This releases heat.

Question 14

What is an endotherm?

Answer 14

An organism that regulates its body temperature internally.

Question 15

What is an ectotherm?

Answer 15

An organism that relies on its environment to regulate its body temperature.

Question 16

How is blood glucose controlled?

Answer 16

• The Islets of Langerhans (Regions in the pancreas with endocrine function).
• Insulin (Helps to use sugar for energy).
• Glucagon (If your blood sugar is low this is released, signalling the liver to release stored glucose).
• Alpha cells (Produce glucagon to increase blood sugar).
• Beta cells (Produce and release insulin).
• Glycogenesis (When glucose is stored in the body as glycogen).
• Glycogenolysis (When glycogen is turned into glucose when a quick source of energy is needed).
• Gluconeogenesis (When new glucose are created from non-carbohydrate sources like amino acids and glycerol).

Question 17

What are the Islets of Langerhans?

Answer 17

Regions in the pancreas with endocrine function, that contain alpha and beta islet cells.

Question 18

What does insulin do?

Answer 18

Helps blood sugar enter the body’s cells so it can be used for energy.

Question 19

What does glucagon do?

Answer 19

If your blood sugar is low this is released, signalling the liver to release stored glucose.

Question 20

What do alpha cells do?

Answer 20

Produce glucagon to increase blood sugar.

Question 21

What do beta cells do?

Answer 21

Produce and release insulin.

Question 22

What is glycogenesis?

Answer 22

When glucose is stored in the body as glycogen.

Question 23

What is glycogenolysis?

Answer 23

When glycogen is turned into glucose when a quick source of energy is needed.

Question 24

What is gluconeogenesis?

Answer 24

When new glucose are created from non-carbohydrate sources like amino acids and glycerol.

Question 25

What does the pancreas do?

Answer 25

• The pancreas detects any changes in the levels of glucose in the blood.
• The Islets or Langerhans are a region in the pancreas that releases insulin and glucagon to regulate the blood glucose levels.

Question 26

What does the pancreas do if your glucose levels are too high?

Answer 26

• Insulin is released from the beta cells of the islets of langerhans in the pancreas, when high levels of glucose are detected.
• It binds to the insulin receptors of the liver which stimulates the conversion of glucose to glycogen and glucose to fat (glycogenesis).
• This causes the levels of glucose to drop.

Question 27

How does adrenaline affects your blood glucose levels?

Answer 27

Adrenaline is released by the adrenal glands if your body anticipates danger. This results in more glucose being released from the stores of glycogen in the liver.

Question 28

How is glucose stored in the body?

Answer 28

• Insulin binds with cell surface receptors on the liver, causing a change in the tertiary structure of the glucose transport protein channels.
• The channels then open and glucose diffuses in.
• This increases the rate of absorption of glucose into the body cells. This is particularly muscle cells and is then used for respiration.

Question 29

What does the pancreas do if your glucose levels are too low?

Answer 29

• This is detected by the alpha cells of the islets of langerhans in the pancreas. These cells produce glucagon which binds to the receptors of the liver cells.
• This stimulates the conversion of glycogen to glucose (glycogenolysis). Other biological molecules like amino acids and glycerol will also be used to be converted into glucose (gluconeogenesis).
• This causes an increase in blood glucose levels.

Question 30

What does the hypothalamus do?

Answer 30

Its main function is to keep your body in a stable state called homeostasis. It does its job by directly influencing your autonomic nervous system or by managing hormones