Endocrinology

Question 1

What is endocrinology?

Answer 1

Study of hormones and their gland of origin, their receptors, intracellular signalling pathways and their associated diseases

Question 2

Endocrine glands release hormones directly into the?

Answer 2

Blood

Question 3

Define endocrine

Answer 3

glands that pour secretions directly into the bloodstream without ducts

Question 4

Define exocrine

Answer 4

glands that pour secretions through a duct to a site of action

Question 5

Paracrine hormone action

Answer 5

acting on nearby adjacent cells

Question 6

Autocrine hormone action

Answer 6

feedback on the same cell that secreted hormone - acts on itself

Question 7

Features of water soluble hormones?

Answer 7

unbound when transported, bind to surface receptor on cells, short half-life, e.g. peptides

Question 8

Features of fat soluble hormones?

Answer 8

transported bound to a protein, diffuse into cells, long half-life, e.g. thyroid hormone

Question 9

5 classes of hormone?

Answer 9

peptides, amines, iodothyronines, cholesterol derivatives and steroids

Question 10

Peptide hormones

Answer 10

stored in secretory granules, hydrophilic and water soluble, released in pulses/ bursts e.g. insulin

Question 11

Amine hormone examples

Answer 11

dopamine, adrenaline, noradrenaline

Question 12

synthesis flowchart of adrenaline

Answer 12

phenylalanine, L-tyrosine, L-dopa, dopamine, noradrenaline, adrenaline

Question 13

Enzyme that breaks down noradrenaline into normetanephrine and adrenaline into metanephrine?

Answer 13

COMT (catechol-o-methyl transferase)

Question 14

What are metanephrines?

Answer 14

Breakdown products of catecholamines

Question 15

Normetanephrine and metanephrine can be measured in serum - what are their levels indicative of?

Answer 15

noradrenaline/ adrenaline activity

Question 16

Iodothyronine hormones bind to what protein in transport?

Answer 16

thyroid binding globulin (TBG)

Question 17

T3

Answer 17

Triiodothryonine - more active, less prevalent

Question 18

T4

Answer 18

thyroxine - less active, more produced

Question 19

TSH

Answer 19

stimulates the movement of colloid into the secretory cell, T4 and T3 are cleaved from thyroglobulin

Question 20

Cholesterol derivative and steroid hormones

Answer 20

e.g. vitamin D, adrenocortical and gonadal steroids

Question 21

Steroid hormone receptor location

Answer 21

cytoplasm

Question 22

Thyroid hormone receptor location

Answer 22

nucleus

Question 23

Hormone secretion patterns

Answer 23

• Continuous release e.g. prolactin
• Pulsatile e.g. insulin
• Circadian rhythm e.g. ACTH, GH, TSH

Question 24

Synergism

Answer 24

Combined effects of two hormones amplified (e.g. glucagon with adrenaline)

Question 25

Antagonism

Answer 25

One hormone opposes the other hormone e.g. glucagon

Question 26

Appetite

Answer 26

Desire to eat food

Question 27

Satiety

Answer 27

Feeling of fullness

Question 28

BMI

Answer 28

``` weight (kg) / height (m^2) <18.5 - underweight 18.5 - 24.9 - normal 25.0 - 29.9 - overweight 30.0 - 39.9 - obese > 40.0 - morbidly obese ```

Question 29

Risks of obesity

Answer 29

type 2 diabetes, hypertension, coronary artery disease, stroke, osteoarthritis, obstructive sleep apnoea, carcinoma

Question 30

Region of brain which plays a central role in appetite regulation?

Answer 30

hypothalamus

Question 31

Leptin (comes from the Greek meaning thin)

Answer 31

Hormone made predominantly by adipocytes (white fat) and enterocytes in the small intestine that helps regulate energy balance by INHIBITING hunger (i.e. diminishing fat stores in adipocytes)

Question 32

Peptide YY

Answer 32

- 36 amino acids - structurally similar to NPY, binds to NPY receptors - secreted by neuroendocrine cells in the ileum, pancreas and colon in response to food - Inhibits gastric motility ('brake') - reduces appetite

Question 33

Main function of peptide YY

Answer 33

reduce appetite - limit food intake

Question 34

NPY - neuropeptide Y

Answer 34

peptide in the brain which stimulates food intake

Question 35

CCK - cholecystokinin

Answer 35

- delays gastric emptying - stimulates gall bladder contraction and sphincter of Oddi relaxation - insulin release - satiety via the vagus

Question 36

Hormone expressed in the stomach which stimulates hunger?

Answer 36

ghrelin