Pancreas

Question 1

What is an exocrine gland?

Answer 1

produces enzymes and releases them into a duct via the duodenum

Question 2

What is an endocrine gland?

Answer 2

produces hormones and releases them into the blood.

Question 3

What is the role of the pancreas as an exocrine gland?

Answer 3

To produce and secrete amylases, proteases and lipase into the pancreatic duct which are then released into the duodenum.

Question 4

What is the role of the pancreas as an endocrine gland?

Answer 4

Produces insulin and glucagon which are released directly into the blood stream at specific times to help regulate blood glucose levels.

Question 5

What is the small region of endocrine tissue called found in the pancreas?

Answer 5

Islets of Langerhans

Question 6

What are the two main types of cells found in the islets of langerhans and what does each secrete?

Answer 6

Alpha cells- produce and secrete glucagon

Beta cells- produce and secrete insulin

Question 7

What is the shape of the islets of langerhans?

Answer 7

large spherical clusters.

Question 8

What is the shape of the pancreatic acini?

Answer 8

small berry-like clusters

Question 9

What is the normal concentration that blood glucose is maintained at?

Answer 9

90 mg cm^-3

Question 10

How can blood glucose conc. increase as a result of diet?

Answer 10

By eating carbohydrate-rich foods, the carbohydrates are broken down and glucose is released into the blood stream.

Question 11

Blood glucose concentration can increase as a result of glycogenolysis. What is this?

Answer 11

Glycogen stored in the liver and muscle cells is broken down into glucose.

Question 12

What is the name for the production of glucose from non-carb sources like from adding glucose to glycerol and amino acids?

Answer 12

Gluconeogenesis

Question 13

What two main ways cause a decrease in blood glucose concentration levels?

Answer 13

Respiration and Glycogenesis

Question 14

What is glycogenesis?

Answer 14

production of glycogen by converting excess glucose in the diet.

Question 15

How does insulin act to reduce the concentration of glucose in the blood after a sugary meal has been eaten?

Answer 15

Beta cells detect the rise in blood glucose conc.
They produce and secrete insulin into the bloodstream.
Insulin in the blood lowers BGC by:
1) increase rate of glucose absorption by cells
2) increase respiratory rate of cells
3) increase rate go glycogenesis in the liver
4) increase rate of glucose to fat conversion
5) inhibit release of glucagon from alpha cells

Question 16

How does glucagon help to increase the concentration of glucose in the blood?

Answer 16

Alpha cells detect the decrease in blood glucose concentration.
They produce and secrete glucagon into the bloodstream.
Glucagon increases BGC by:
1) glycogenolysis- liver breaks down glycogen store into glucose and releases it.
2) reduces the amount of glucose absorbed by liver cells.
3) increases gluconeogenesis- conversion of amino acids and glycerol into glucose.

Question 17

When does negative feedback occur in the control of blood glucose levels?

Answer 17

When levels fall below a set level, the B cells stop producing as much insulin.
When levels rise above a set level, the a cells stop their secretion of glucagon.

Question 18

Insulin and glucagon are antagonistic hormones. What does this mean?

Answer 18

They work against each other but also together to maintain the correct level of blood glucose concentration.

Question 19

What is the mechanism by which insulin is secreted?

you can bullet point the process step by step

Answer 19

1) At normal BGC levels, K+ channels are open on membrane of B cells. K+ ions diffuse out of the cell and the inside of the cell is at -70mV.
2) BGC rises and glucose enters the cell by a glucose transporter
3) Glucose is metabolised in mitochondria and ATP is made.
4) ATP binds to ATP-sensitive potassium channels causing them to close.
5) No K+ diffuse out so the pd reaches -30mV. Depolarisation occurs.
6) Depolarisation causes voltage-gated calcium channels to open.
7) Ca2+ enter cell and cause secretory vesicles to release insulin.

Question 20

What are the common symptoms of diabetes?

Answer 20

High blood glucose conc.
Glucose in urine
Excessive need to urinate
Excessive thirst
Constant hunger
Weight loss
Blurred vision 
Tiredness

Question 21

What is the cause of Type 1 diabetes?

Answer 21

Unknown cause.
However, we know that the B cells in the pancreas cannot produce insulin in patients with type 1 diabetes.
Possibly because the body attacks and destroys its own B cells as an autoimmune disease.

Question 22

What is the cause of Type 2 diabetes?

Answer 22

The persons B cells don’t produce enough insulin or the persons body doesn’t respond efficiently to the insulin being released.
Due to obesity, overeating, little to no exercise

Question 23

How is type 1 diabetes treated?

Answer 23

Regularly check blood glucose levels by pricking their finger and analyzing the blood in a machine.
They inject the insulin in their body regularly.

Question 24

How is type 2 diabetes treated?

Answer 24

Increasing exercise levels.
Follow a uniquely tailored diet plan
Drugs are taken that stimulate insulin production.

Question 25

What are the advantages of producing insulin by genetically modifying bacteria?

Answer 25

Human insulin is produced in a pure form.(less likely to cause allergic reactions)
Insulin is made in higher quantities
Production costs are cheaper
Overcome ethical and religious issues of using animal insulin.

Question 26

What are the advantages of using stem cells to treat diabetes?

Answer 26

• Donor availability won’t be an issue- stem cells produce an unlimited amount of B cells.
• Reduced likelihood of rejection as embryonic stem cells are not rejected by the body.
• People don’t need to inject themselves with insulin.