Endocrine System

Question 1

Examples of amino acid-based hormones

Answer 1

Protein and peptide hormones (e.g., insulin, glucagon)

Amines and amino acids (e.g., adrenaline)

Question 2

Examples of steroid hormones

Answer 2

Cortisol, oestrogen, testosterone

Question 3

How do amino acid-based hormones act?

Answer 3

Water soluble
Travel in blood freely
Bind to cell surface receptor (polar so can’t cross lipid membrane)

Question 4

How do steroid hormones act?

Answer 4

Lipid soluble
Therefore, have to travel in blood bound to a carrier
Bind to intracellular receptor

Question 5

3 types of hormone regulation and what they do? Examples?

Answer 5

1. Hormonal stimuli – hormones stimulate other endocrine glands to secret hormones.
2. Neural Stimuli – nerve fibres stimulate hormone release.
   E.g., SNS stimulating adrenaline and noradrenaline
3. Humoral Stimuli – changes in ion or nutrients in the blood stimulate secretion of hormones.
   E.g., Calcium in the blood

Question 6

Define primary disorder: example?

Answer 6

Originate in target organ releasing the hormone

E.g., thyroid gland

Question 7

Define secondary/tertiary disorder: example?

Answer 7

Defect in hypothalamus-pituitary system

E.g., thyroid gland will involve altered levels of TSH

Question 8

Hypofunction causes?

Answer 8

1. Congenital defects resulting in absence or impaired development of a gland
2. Absence of an enzyme
3. Destruction of a gland (due to infection, autoimmune response, neoplastic growth and decreased blood flow)
4. Atrophy of a gland (due to medication)
5. Defective receptor sites
6. Response to hormone is diminished

Question 9

Hyperfunction causes?

Answer 9

1. Excessive hormone production due to overstimulation of a gland
2. Hormone producing tumour
3. Autoimmune disorder

Question 10

What is a stimulation test?

Answer 10

Tests for HYPOFUNCTION
Stimulating hormones administered to test ability of an endocrine organ to increase hormone production
E.g., ACTH stimulation test

Question 11

What is a suppression test?

Answer 11

Tests for HYPERFUNCTION
Give external stimulus for the endocrine organ
E.g., Dexamethasone suppression test

Question 12

What are the tests used to examine endocrine function?

Answer 12

Suppression test
Stimulation test
Blood
Imaging

Question 13

Causes of hyperthyroidism?

Answer 13

Graves’ Disease common.
Hypermetabolic state
Increase in SNS activity

Question 14

Cause of primary hypothyroidism?

Answer 14

Autoimmune disorder

E.g. Hashimotos, thyroidectomy, ablation, iodine deficiency

Question 15

Insulin stimulates:

Answer 15

Uptake, use and storage of glucose 
Glycogenesis 
ATP
Lipogenesis
Protein synthesis

Question 16

Insulin inhibits:

Answer 16

Glycogenolysis
Gluconeogenesis
Lipolysis
Protein breakdown

Question 17

Type 1 Diabetes:

Answer 17

Absolute deficiency of insulin
Autoimmune – cell-mediated destruction of pancreatic beta cells
Non-immune – no immune responses / antibodies

Question 18

Type 2 Diabetes:

Answer 18

Body is resistant to insulin

Characterised by: insulin resistance, B-cell dysfunction, hyperglycaemia

Question 19

What is Intermediate hyperglycaemia?

Answer 19

Biochemical state where a person has impaired fasting glucose and/or impaired glucose tolerance

HbAc1 level = 41-49mmol/mol

Question 20

What is Metabolic Syndrome?

Answer 20

Have 3 out of the 5 following:

1. Abdominal obesity
2. Increased fasting plasma glucose
3. Increased BP
4. Increased serum triglycerides
5. Decreased high-density cholesterol levels

Question 21

Complications of diabetes mellitus?

Answer 21

1. Hypoglycaemia
2. Diabetic ketoacidosis
3. Hyperosmolar hyperglycaemia state
4. Microvascular disease
5. Macrovascular disease
6. Infection
7. Impaired wound healing

Question 22

What is diabetic ketoacidosis?

Answer 22

Hyperglycaemia, ketosis and metabolic acidosis

Question 23

The correct sequence of events leading up to the secretion of T3 is

Answer 23

Hypothalamus releases TRH, anterior pituitary releases TSH, thyroid releases T4, T4 converts to T3