Module 5: The Pancreas

Question 1

The pancreas predominantly consists of what type of tissue?
What is this tissue mainly made up of?

Answer 1

exocrine glandular tissue , mainly made up of pancreatic acini

Question 2

What do pancreatic acini contain?

What do these structures produce? 2

Answer 2

acinar cells that produce digestive enzymes such as amylases/proteases and lipases
-they also produce alkaline pancreatic juice

Question 3

Where do the substances produced by acinar cells travel ?

What is the duodenum?

Answer 3

they travel through the pancreatic duct and are released into the duodenum where they assist in digestion

the initial segment of the small intestine

Question 4

Make 2 points about how the pancreas can act as an endocrine gland

Answer 4

-by using specialised clusters of cells called islets of Langerhans
-the cells within these islets secrete different hormones directly into the blood stream

Question 5

Name the 2 types of cells within the islets of Langerhans and name the hormone they secrete

What are these hormones important for?

Answer 5

beta cells-produce and secrete insulin
alpha cells-produce and secrete glucagon

regulating blood glucose levels

Question 6

Give 2 reasons why its vital for us to regulate our blood glucose concentration

Answer 6

-glucose is essential for cellular respiration
-extreme levels of glucose can cause osmotic imbalances in cells which can lead to cell death

Question 7

When glucose levels increase , insulin acts to reduce these levels using what 4 mechanisms?

Answer 7

-inhibition of alpha cells which reduces glucagon secretion
-insulin increases the permeability of muscle and fat cells to glucose which increases glucose uptake
-increasing respiration rate so that more glucose is broken down to produce ATP
-conversion of glucose into glycogen in the liver(glycogenesis)

Question 8

When glucose levels decrease , glucagon acts to increase levels through what 4 mechanisms?

Answer 8

-inhibition of beta cells to decrease insulin secretion
-reduced respiration rate to decrease breakdown of glucose
-glycogenolysis , increased conversion of glycogen into glucose in liver and muscle cells
-gluconeogenesis , new glucose molecules synthesised in liver cells using amino acids and glycerol

Question 9

Name another hormone that works alongside glucagon to increase blood glucose concentration
-state how it does this

Answer 9

adrenaline, it promotes glycogenolysis and gluconeogenesis in the liver and muscle cells

Question 10

Describe the 6 step process of how insulin is secreted by beta cells

Answer 10

1)glucose enters beta cells via transporter proteins

2)increase in glucose in cells results in increased cellular respiration in mitochondria which produces more ATP

3)ATP binds to ATP sensitive potassium ion channels causing them to close

4)this causes an increase in potassium ion concentration inside the beta cells

5)this leads to depolarisation of cells , causing calcium ion channels to open

6)calcium ion influx causes release of insulin from vesicles via exocytosis

Question 11

Why must insulin constantly be secreted?

Answer 11

because it is easily broken down by enzymes in the liver