Hormonal Regulation of Glucose Homeostasis

Question 1

What are normal fasting blood glucose levels?

Answer 1

3.9-5.4 mmol/L

Question 2

What are normal blood glucose levels two hours after starting a meal?

Answer 2

6-10 mmol/L

Question 3

What is blood glucose levels for hypoglycaemia?

Answer 3

<4 mmol/L

Question 4

What is blood glucose levels for hyperglycaemia?

Answer 4

> 7 mmol/L

Question 5

What are signs and symptoms of hypoglycemia?

Answer 5

• Shaking, trembling or weakness
• Sweating
• Hunger
• Headache
• Dizziness

Question 6

What are signs and symptoms of hyperglycemia?

Answer 6

• Excessively thirsty
• Frequently passing large volumes of urine
• Feeling tired

Question 7

What hormones can increase blood glucose levels?

Answer 7

Glucagon, growth hormone, adrenaline and cortisol

Question 8

What does glucagon do?

Answer 8

Breaks down glycogen to glucose

Question 9

What hormones can decrease blood glucose levels?

Answer 9

Only insulin

Question 10

What does insulin do?

Answer 10

Converts glucose into glycogen which can be stored as fat

Question 11

What are the steps that happen when blood glucose decreases?

Answer 11

• Pancreatic alpha islet cells release glucagon
• Glucagon triggers gluconeogenesis and glycogenolysis in liver
• Glucose is released back into blood

Question 12

What is gluconeogenesis?

Answer 12

Process where glucose is formed from noncarbohydrate sources

Question 13

What is it called when glucose is formed from noncarbohydrate sources?

Answer 13

Gluconeogenesis

Question 14

What is glycogenolysis?

Answer 14

Process of breaking down glycogen into glucose

Question 15

What is the process of breaking down glycogen into glucose called?

Answer 15

Glycogenolysis

Question 16

What are the steps that happen when blood glucose increases?

Answer 16

• Pancreatic beta islet cells release insulin
• Insulin stimulates glucose uptake by cells and stimulate glycogenesis in the liver

Question 17

What is glycogenesis?

Answer 17

The process of converting glucose into glycogen

Question 18

What is the process of converting glucose into glycogen called?

Answer 18

Glycogenesis

Question 19

What is the role of the kidney in maintaining blood glucose levels?

Answer 19

It absorbs excess glucose and removes it via urine

Question 20

Where can the beta cells be found in a pancreatic islet?

Answer 20

In the centre/core

Question 21

Where can alpha cells be found in a pancreatic islet?

Answer 21

Around the edge

Question 22

What does GLUT2 do?

Answer 22

Transports glucose into the ceta cell

Question 23

What happens to glucose in the beta cell?

Answer 23

Phosphorylated into G6P by glucokinase

Question 24

What is glucokinase?

Answer 24

An enzyme that converts glucose into G6P

Question 25

What does G6P become?

Answer 25

It moves through the glycolysis pathway to form pyruvate which enters the Krebs cycle to produce ATP

Question 26

What happens in beta cells when ATP increases?

Answer 26

The ATP binds and closes ATP sensitive K+ channels

Question 27

What happens when the K+ channels are closed in beta cells?

Answer 27

Depolarisation of plasma membrane resulting in the voltage sensitive Ca2+ channels opening

Question 28

What does the influx of Ca2+ in beta cells do?

Answer 28

Triggers insulin granule exocytosis

Question 29

What are the steps to releasing insulin from the beta cells?

Answer 29

- GLUT2 transports glucose in which is converted into G6P - G6P becomes pyruvate which generates ATP - Increased ATP closes K+ channels resulting in depolarisation of plasma membrane - Ca2+ channels opens triggering insulin release

Question 30

What does GLUT4 do?

Answer 30

Is a glucose transporter which is active when there is an increase of insulin and allows the uptake of glucose

Question 31

Are GLUT4s always present?

Answer 31

No they are only in the membrane when there are high levels of insulin once glucose levels have dropped they are removed

Question 32

What does type 1 diabetes mean?

Answer 32

Absolute deficiency of insulin

Question 33

What does type 2 diabetes mean?

Answer 33

Relative deficiency of insulin/ insulin resistance

Question 34

What causes type 1 diabetes?

Answer 34

Autoimmune condition where the immune system kills beta cells

Question 35

What does a healthy level of insulin look like after eating in comparison to diabetic?

Answer 35

Healthy has a high spike in insulin after eating whilst there is no spike in diabetic people

Question 36

What does a healthy level of glucose look like after eating in comparison to diabetic?

Answer 36

Healthy has a slight increase in glucose levels whilst in diabetic the glucose levels get much higher