Pathogenesis and abnormal metabolism

Question 1

What percentage of the total population is affected by diabetes in the UK?

Answer 1

6%

Approximately 3.9 million people are known to have diabetes in the UK.

Question 2

What is diabetes mellitus?

Answer 2

A condition associated with an elevated blood glucose due to deficiency of insulin or insulin resistance

It can result from a combination of both factors.

Question 3

What is the role of insulin in the body?

Answer 3

An anabolic hormone essential for fuel storage and cell growth

It promotes glucose uptake into cells for energy and prevents the breakdown of fat and protein.

Question 4

What are the main types of pancreatic cells and their hormones?

Answer 4

• Alpha cell: Glucagon (11%)
• Beta cell: Insulin (85%)
• Delta cell: Somatostatin (3%)
• F cell: Pancreatic polypeptide (1%)

Question 5

What triggers the secretion of insulin from beta cells?

Answer 5

Glucose influx

Pro-insulin is converted to insulin and C-peptide in equimolar amounts.

Question 6

What is the biphasic response of insulin secretion?

Answer 6

Stored insulin is released first, followed by newly synthesized insulin

This occurs in response to food ingestion.

Question 7

What physiological effects does insulin have?

Answer 7

• Increases glucose uptake in fat and muscle
• Promotes glycogen storage in liver and muscle
• Enhances amino acid uptake and protein synthesis
• Stimulates lipogenesis in adipose tissue
• Decreases gluconeogenesis and ketogenesis

Question 8

What is GLUT 4?

Answer 8

A glucose transporter that is translocated to cell membranes by insulin

This process allows insulin-dependent glucose uptake into cells.

Question 9

What is the normal fasting plasma glucose level?

Answer 9

< 7.0 mmol/l

Question 10

What are the diagnostic criteria for diabetes?

Answer 10

• Fasting plasma glucose > 7.0 mmol/l
• 2hr plasma glucose in OGTT > 11.1 mmol/l
• Random plasma glucose > 11.1 mmol/l
• HbA1c > 48 mmol/mol

Question 11

What is the significance of HbA1c in diabetes management?

Answer 11

It reflects integrated blood glucose concentrations over the lifespan of erythrocytes

HbA1c is used to evaluate treatment efficacy and risk of complications.

Question 12

What characterizes impaired glucose tolerance (IGT)?

Answer 12

Fasting plasma glucose < 7.0 mmol/l and 2 hours after 75g oral glucose load: 7.8-11.0 mmol/l

It affects about 20% of the population aged 40-65 years in the UK.

Question 13

What is pre-diabetes defined by?

Answer 13

• Fasting blood glucose 6.0-6.9 mmol/l
• 2 hr OGTT blood glucose 7.8-11.0 mmol/l
• HbA1c 42-47 mmol/mol

Question 14

True or False: Diabetes mellitus has only one potential cause.

Answer 14

False

Diabetes mellitus can result from multiple potential causes including Type 1, Type 2, and other syndromes.

Question 15

What are severe insulin resistance syndromes?

Answer 15

• Leprechaunism
• Rabson-Mendenhall syndrome
• Type A insulin resistance

Question 16

What is the relationship between visceral fat and insulin resistance?

Answer 16

Visceral fat is more metabolically active than subcutaneous fat

This contributes to increased insulin resistance.

Question 17

What are the common causes of elevated HbA1c levels?

Answer 17

• Rapid onset diabetes
• Type 1 diabetes
• Certain medications (e.g., steroids)
• Pregnancy
• Hemoglobinopathies

Question 18

What is the role of glucagon in glucose metabolism?

Answer 18

It favors glycogenolysis and gluconeogenesis

Glucagon acts oppositely to insulin.

Question 19

What is the hallmark of diabetes?

Answer 19

Hyperglycemia

Question 20

What percentage of acute hospital beds are occupied by patients with diabetes?

Answer 20

17%

Question 21

Fill in the blank: Insulin is essential for _______.

Answer 21

[fuel storage and cell growth]