Pancreas

Question 1

What is the name of the group of secretory cells? What epithelium is it lined with?

Answer 1

Groups of acini

Simple cuboidal

Question 2

What is the function of the exocrine and endocrine pancreas?

Answer 2

Exocrine = digestion
Endocrine = regulation of metabolsim

Question 3

What are the two major components of pancreatic juice?

Answer 3

Bicarbonate ions - neutralise stomach acid

Enzymes - digest food material for absorption

Question 4

When does pancreatic juice remain highly alkaline and why?

Answer 4

At high flow rates e.g. during digestion it remains highly alkaline as there is not enough time for bicarbonate reabsorption

Question 5

Duodenal epithelial surface contains enteropeptidase, what is the role of this enzyme?

Answer 5

Activates trypsinogen into trypsin, this then activates proteases

Question 6

What is the intestinal phase of digestion in the pancreas regulated by?

Answer 6

It is the hormonal phase so is regulated by secretin and CCK

Question 7

What is secretin released in response to and what is its role?

Answer 7

Released from duodenum in response to hydrogen ions

It increases bicarbonate secretion

Question 8

What is CCK released in response to?

Describe how it works as a positive feedback mechanism

Answer 8

Released from duodenum in response to fat / protein metabolites
- Increased enzyme secretion produce more metabolites which in turn stimulate further CCK release

Question 9

What is the name of the clusters of cells scattered through pancreatic tissue?

Answer 9

islets of Langerhans

Question 10

What is insulin released in response to, what is the overall effect of its secretion?

Answer 10

• increased plasma levels of glucose and amino acids

- anabolic effect

Question 11

How is insulin de-activated in the liver?

Answer 11

Cleavage of di-sulphide bonds

Question 12

Describe the bi-phasic secretion of insulin

Answer 12

• Initial immediate secretion of stored insulin lasting 5-15 mins
• Followed by more prolonged secretion of newly synthesised insulin adjusted to plasma levels of glucose

Question 13

Activity of which part of the ANS increases insulin secretion?

Answer 13

Parasympathetic NS

- long reflex arc

Question 14

How does insulin help to enhance glucose uptake?

Answer 14

Mobilisation of glucose transporter GLUT4 to cell membranes

Question 15

Where does insulin mostly act to increase the conc of intra-cellular enzymes involved in metabolism?

Answer 15

Liver
Skeletal muscle
Adipose tissue

Question 16

What is the name for when plasma glucose is elevated?

Answer 16

Hyperglycaemia

Question 17

How do type 1 and type 2 diabetes differ?

Answer 17

Type 1 = insulin dependent
- insulin production impaired
Type 2 = non-insulin dependent
- insulin production normal but cells resistant to its effects

Question 18

What is glucosuria?

Answer 18

When the capacity for the kidneys to re-absorb glucose is exceeded

Question 19

When is glucagon secreted and what is the overall effect?

Answer 19

In response to decreased levels of glucose and amino acids

- overall catabolic effect