Chapter 10 part 3: regulation of blood glucose concentration

Question 1

what are the requirements that body cells need for cellular respiration?

Answer 1

• body cells need glucose for cellular respiration.
• equation for cellular respiration: glucose + oxygen –> carbon dioxide + water

Question 2

what is the by-product of cellular respiration?

Answer 2

• cellular respiration provides cells with energy for vital activities.

Question 3

what is a normal blood glucose level?

Answer 3

• normal blood glucose levels are about 70-90 mg of glucose per 100 cm3 of blood.
• levels drastically above or below this can be DANGEROUS.

Question 4

what can result in an increase in blood glucose levels?

Answer 4

• after a meal rich in carbohydrates and fall after exercise or starvation can result in an increase in the blood glucose levels.

Question 5

how do we regulate the blood glucose concentration in humans?

Answer 5

• the islets of langerhans in the pancreas secretes insulin, and glucagon.

Question 6

what is insulin and how can insulin decrease blood glucose concentration?

Answer 6

• insulin is a hormone that is porduced in the pancreas by the islets of langerhans which regulates the amount of glucose that is present in the blood.
• the lack of insulin results in a form of diabetes.
• insulin decreases blood glucose concentration by:
  1. increasing the permeability of the cell membranes to glucose thus increasing the rate of glucose uptake by cells.
  2. stimulating the liver and muscle cells to convert glucose into glycogen for storage.
  3. increasing the use of glucose during tissue respiration.

Question 7

what is glucagon and how can glucagon decrease blood glucose concentration?

Answer 7

• glucagon is a hormone that is formed in the pancreas which promotes the breakdown of glucose in the liver.
• glucagon increases blood glucose concentration by:
  1. converting glycogen into glucose
  2. converting fats and amino acids into glucose.

Question 8

how does the homeostasis control of high blood glucose concentration take place?

Answer 8

1. first stimulus: blood glucose concentration rises above normal levels

RECEPTOR AND CONTROL CENTRE:
- islets of langerhans in the pancreas are stimulated.

CORRECTIVE MECHANISM:
- islets of langerhans secrete insulin into the bloodstream.
- blood transports insulin to the liver and muscles.
- insulin increases glucose absorption by the cells.
- excessive glucose is converted into glycogen which is stored in the liver and muscles.

RESULT:
- blood glucose concentration drops to normal.
- insulin production decreases.

Question 9

how does the homeostasis control of low blood glucose concentration take place?

Answer 9

2. second stimulus: blood glucose concentration falls below normal levels

RECEPTOR AND CONTROL CENTRE:
- islets of langerhans in the pancreas are stimulated.

CORRECTIVE MECHANISM:
- islets of langerhans secrete glucagon into the bloodstream.
- blood transports glucagon to the liver and muscles.
- stored glycogen is converted into glucose.
- glucose enters the bloodstream from the liver.

RESULT:
- blood glucose concentration rises to normal.
- glucagon production decreases.

Question 10

what is diabets mellitus?

Answer 10

• diabetes mellitus is a disease in which the body is unable to regulate its blood glucose concentration due to either insufficient insulin produced or the body’s resistance to insulin.
• this disease causes the blood glucose concentration to rise to a level where the nephrons in the kidney cannot reabsorb all the glucose fast enough. this results in glucose being excreted in urine.

Question 11

what are the symptoms of diabetes mellitus?

Answer 11

• persistently high blood glucose level.
• glucose in urine.
• slow healing of wounds.
• frequent urination.
  (too much urea)
• weight loss
• thirst.

Question 12

what are the 2 main types of diabetes?

Answer 12

1. type 1 diabetes:
   - inherited condition early in life.
   - known as juvenile or early-onset diabetes.
   - islets of langerhans are unable to product/secrete sufficient insulin.
2. type 2 diabetes:
   - developes in adulthood.
   - known as late-onset diabetes.
   - targets cells (muscle cells) do not respond well to insulin. (INSULIN RESISTANCE)

Question 13

how can diabetes be managed?

Answer 13

1. monitor blood glucose concentration regularly.
2. regulate diet and carbohydrate intake.
3. take medication to increase the uptake of glucose into cells.
4. take insulin injections.

Question 14

what are the 4 main factors that increases the risk of type 2 diabetes?

Answer 14

1. obesity:
   - obesity increases the risk of getting type 2 diabetes.
2. age:
   - risk of getting type 2 diabetes increases as you age.
3. family/history:
   - if you have family members with diabetes, you are at greater risk of developing it as well.
4. blood lipid levels:
   - high levels of ‘bad’ cholesterol and low levels of ‘good’ cholesterol increases the risk of type 2 diabetes.

Question 15

what are the ways that we can reduce the risk of developing type 2 diabetes?

Answer 15

• healthy lifestyle:
  1. eating healthily
  2. engaging in regular physical activity
  3. avoiding long periods of inactivity
  4. maintaining healthy body weight by eating less sweet/salty/oily foods to reduce excess bloating and excess weight gain.