Introduction to endocrinology

Question 1

What is endocrinology?

Answer 1

The study of biosynthesis, secretion, regulation and action of hormones as well as glands and tissues that produce them

Question 2

What is a hormone?

Answer 2

A chemical substance formed in glands that is carried in the bloodstream to affect another part of the body

Question 3

What is an endocrine organ?

Answer 3

Glands that secrete their products (hormones) directly into the bloodstream rather than through a duct (exocrine)

Question 4

Name 3 hormone groups

Answer 4

1) Amine
2) Peptide
3) Steroid

Question 5

Define amines and list examples

Answer 5

Are derived from a single amino acid

Epinephrine/norepinephrine/dopamine (tyrosine)

Question 6

Define peptides and list examples

Answer 6

Peptides are derived from multiple amino acids (3-200)
They are all pituitary hormones
Insulin/leptin/ghrelin

Question 7

Define steroids and list examples

Answer 7

Steroids are derived from cholesterol

glucocorticoids/mineralcorticoids/androgens/progesterone

Question 8

Describe the function of the pituitary gland

Answer 8

Endocrine ‘master gland’
crucial connection between the endocrine and nervous system
consists of anterior and posterior lobes

Question 9

List 5 hormones that are produced by the anterior lobe of the pituitary gland

Answer 9

Adrenocoticotrophic hormone (ACTH)
Thyroid stimulating hormone (TSH)
Follicle and luteinising stimulation hormone (FSH/LH)
Growth hormone (GH)
Prolactin

Question 10

Which hormones are secreted by the thyroid gland?

Answer 10

Thyroxine (T4) and triiodothyronine (T3) are produced by iodination of thyroglobulin in response to TSH from the anterior pituitary

Question 11

What is the function of thyrorid hormones?

Answer 11

To regulate body metabolism and ensure healthy cellular development

Question 12

List common disorders of the thyroid

Answer 12

Hyperthyroidism
Hypothyroidism
Adenoma/goitre
Cancer

Question 13

How are the adrenal glands regulated?

Answer 13

Through the ACTH and renin-angiotensin system

Question 14

Which hormones are produced by the adrenal cortex?

Answer 14

Corticosteroid hormones:
cortisol
aldosterone
androgens

Question 15

Which hormones are produced by the adrenal medulla

Answer 15

Catecholamines:
Epinephrine
Norepinephrine
Dopamine

Question 16

List the main disorders of the adrenal glands

Answer 16

Insufficiency - Addison’s

Excess activity - Cushing’s, primary aldosteronism, phaeochromocytoma

Question 17

What are the gonads

Answer 17

Sex organs - testes and ovaries

Question 18

What are the functions of testes

Answer 18

Leydig cells are a source of testosterone in response to LH
Spermatogenesis occurs in Sertoli cells in response to FSH
Also produces other androgens (androstenedione)

Question 19

What are the functions of ovaries

Answer 19

Source of oestrogen and androgen

regulated by FSH/LH

Question 20

Describe the endocrine pancreas briefly including the hormones secreted

Answer 20

consists of islet of langerhans
Insulin is secreted by beta cells
Glucagon is secreted by alpha cells
Somatostatin is secreted by delta cells
Pancreatic polypeptide is secreted by PP cells

Hormones are secreted into the capillaries

Question 21

Decribe the exocrine pancreas

Answer 21

Consists of centroacinar cells that secrete proteases, lipase and amylase.
Secretions are controlled by hormones from the stomach and duodenum.
The pancreatic duct epithelium secretes bicarbonate

Question 22

Describe the action of steroids/ thryroid hormones

Answer 22

Bind to intracellular receptors

The receptor/ligand complex binds DNA to affect transcription

Question 23

Describe the action of G protein coupled receptors

Answer 23

G proteins initiate cellular changes by acting directly on processes (such as ion channels) or through second messengers, which then affect cell proteins to alter function

Question 24

Briefly explain homeostasis in endocrinology

Answer 24

To maintain a physiological parameter within a narrow range of values (e.g. blood glucose concentration), that is perceived by tissues
This leads to a signal from the target organ to communicate to other tissues that can then act to stabilise that parameter

E.g.

Question 25

Briefly explain homeostasis in endocrinology

Answer 25

To maintain a physiological parameter within a narrow range of values (e.g. blood glucose concentration), that is perceived by tissues
This leads to a signal from the target organ to communicate to other tissues that can then act to stabilise that parameter

E.g. simple molecules (O2)
ion currents
other hormones (insulin, steroids)

Question 26

Describe different responses to signals

Answer 26

Positive feedback - amplifying the change
Negative feedback - resisting the change
Feed forward - anticipation of change

Complex processes may have several feedback loops

Question 27

What is the difference between T1DM and T2DM

Answer 27

T1DM is autoimmune and affects 12% of the diabetic population

T2DM includes obesity as a major factor and affects 88% of the population

Question 28

List 3 microvascular complications of DM

Answer 28

Dependent on glycaemic control

• retinopathy
• nephropathy
• neuropathy

Question 29

List 2 macrovascular complications of DM

Answer 29

Dependent on other risk factors

• coronary heart disease equivalent
• inceased risk of stroke/heart attack