Lecture 33: Pancreatic Islets Flashcards Preview

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Flashcards in Lecture 33: Pancreatic Islets Deck (22)
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1
Q

Where is insulin secreted from?

A

The beta cells of the pancreatic islets.

2
Q

Where is glucagon secreted from?

A

The alpha cells of the pancreatic islets.

3
Q

Where are the pancreatic islets found?

A

In the endocrine gland of the pancreas.

4
Q

What is the ONLY fuel that the brain uses?

A

Glucose.

5
Q

What are the two metabolic states the body can be in?

A

Fed state (cellular uptake of nutrients & anabolic metabolism - SYNTHESIS of glycogen, protein and fat)

Fasting state (mobilisation of nutrients and catabolic metabolism - BREAKDOWN of glycogen, protein and fat).

6
Q

What is the reference range of BGL?

A

3.5 - 6 mmol/L

7
Q

Which hormones lowers BGL and which one increases it?

A

Insulin decreases BGL, glucagon increases it.

8
Q

Explain the process of returning to a homeostatic BGL after eating.

A

Digestion - carbs broken down to glucose - causes rise in BGL.

Beta cells secrete insulin.

Insulin targets cells in the liver, muscle and fat, causing them to take up glucose.

BGL decreases.

NOTE THAT FEEDFORWARD SECRETION OF INSULIN ALSO OCCURS.

9
Q

How quickly does the effect of insulin start becoming apparent?

A

Milliseconds. (WS hormone)

10
Q

What is hyperglycaemia?

A

High BGL

11
Q

What is glycosuria?

A

Glucose in urine.

12
Q

What is polyuria?

A

large volumes of urine

13
Q

What is polydipsia?

A

Thirst

14
Q

What is polyphagia?

A

Hunger.

15
Q

What are the symptoms of Type I diabetes mellitus?

A

Hyperglycaemia, glycosuria, polyuria, polydipsia and polyphagia.

16
Q

What is the statistical split between Type I and Type II diabetes?

A

Type I: 10%

Type II: 90%

17
Q

What is the cause of Type I diabetes?

A

Insulin producing beta cells have been destroyed (genetic, autoimmune) -> low insulin levels.

18
Q

What is treatment for type I diabetes?

A

Insulin injections, regular testing.

Possible islet transplantation.

19
Q

What is the cause of Type II diabetes?

A

Cells are resistant to insulin’s signal to store fuel (eg. fewer receptors) -> low insulin level. Obesity, diet, ethnicity, genes and exercise are risk factors.

20
Q

What are complications of diabetes mellitus?

A

Over time, hyperglycaemia damages the body:
Atherosclerosis (leads to heart attacks, strokes)
Kidney disease
nerve damage
retinal changes (blindness)

21
Q

What is gluconeogenesis?

A

Glucose synthesis.

22
Q

What is glycogenolysis?

A

Break down of glycogen.