Endocrinology

Question 1

What does hemocrine mean?

Answer 1

Secretion from cells into extracellular fluid, which then diffuses into blood vessels

Question 2

What does autocrine mean?

Answer 2

Hormone released from the cell acts on the same cell

Question 3

What does paracrine mean?

Answer 3

Hormone released has an effect on nearby cells

Question 4

What does solinocrine mean?

Answer 4

Hormone released into a duct (e.g. GI system)

Question 5

Where are peptide hormones stored?

Answer 5

In vesicles within endocrine cells

Question 6

Which amino acid are the small amino acid hormones based on?

Answer 6

Tyrosine

Question 7

How do peptide hormones act on target cells?

Answer 7

Act on cells with appropriate cell surface receptors; activation of receptor leads to downstream signalling

Question 8

How do steroid hormones act on target cells?

Answer 8

Act at a cytoplasmic or nuclear receptor

Question 9

How do amino acid hormones act on target cells?

Answer 9

Act at nuclear receptors only

Question 10

Which structure acts as the link between the hypothalamus and anterior pituitary?

Answer 10

Hypophyseal portal circulation

Question 11

What is the function of the neuroendocrine cells of the hypothalamus?

Answer 11

Focus point for information on internal well-being - detects circulating hormones/metabolites/electrolytes and stress/cold/trauma/hunger/pain etc.

Question 12

What is the effect of oxytocin released from the PP?

Answer 12

Contraction of uterus in labour, milk let-down in lactation (NEURAL feedback, not hormonal)

Question 13

What is the effect of vasopressin/ADH released from the PP?

Answer 13

Aiding water reabsorption in the kidney

Question 14

What does the thyroid gland look like histologically?

Answer 14

Composed of follicles filled with colloid, lined with cuboidal follicular epithelium, highly vascularised

Question 15

What is thyroid hormone derived from?

Answer 15

Thyroglobulin, a polymer of tyrosine (amino acid)

Question 16

What are the matured thyroid hormones called?

Answer 16

Thyroxine (T3) and tri-iodothyrine (T4)

Question 17

Which thyroid hormone causes most of the physiological effects?

Answer 17

T3 - T4 is typically just a pool for T3 (half-life of 6 days compared to 1 day for T3)

Question 18

What stimulates TRH release from the hypothalamus?

Answer 18

Sympathetic stimulation, or cold

Question 19

What inhibits TRH release from the hypothalamus?

Answer 19

Cortisol and growth hormone

Question 20

How does T3 act on thyroid cells?

Answer 20

Enters cell and nucleus, binds to thyroid hormone receptor (TRH) on the thyroid response element, binding of THR to promoter elements activates gene transcription

Question 21

What does hypertrophy mean?

Answer 21

Increase in cell size

Question 22

What does hyperplasia mean?

Answer 22

Increase in cell number

Question 23

What type of hormone is growth hormone?

Answer 23

A peptide hormone

Question 24

In what form does growth hormone circulate in the body?

Answer 24

Weakly bound to GH-binding protein

Question 25

Where is growth hormone secreted from?

Answer 25

Somatotrophs in the anterior pituitary (stimulated by GHRH)

Question 26

What inhibits release of growth hormone releasing hormone?

Answer 26

Somatostatin

Question 27

In which pattern is growth hormone released?

Answer 27

Diurnally (during sleep) and pulsatile

Question 28

What molecule mediates the local effects of growth hormone?

Answer 28

Insulin-like growth factor (IGF-1)

Question 29

What conditions does excess growth hormone cause?

Answer 29

Giantism or acromegaly

Question 30

What condition does deficiency of growth hormone cause?

Answer 30

Dwarfism

Question 31

Why is it a risk to inject growth hormone into adults?

Answer 31

Encouraging cells to grow when they are naturally stopping may induce cancer

Question 32

What hormones are produced in the adrenal medulla (chromaffin cells)?

Answer 32

Adrenaline and noradrenaline

Question 33

What hormones are produced in the adrenal cortex?

Answer 33

Corticosteroids

Question 34

Which zones make up the adrenal cortex?

Answer 34

Glomerulosa (mineralocorticoids), fasciculata (glucocorticoids), reticularis (androgens and oestrogens)

Question 35

What is the precursor molecule to adrenal steroids?

Answer 35

Cholesterol

Question 36

How do steroids action in cells?

Answer 36

Act on cytoplasmic receptor in target tissues, translocates to the nucleus upon steroid binding, modulates transcription of genes to produce new proteins (and therefore biological effects)

Question 37

In what form does cortisol/corticosterone circulate in the body

Answer 37

Bound to transcortins (plasma proteins)

Question 38

What is the function of aldosterone (mineralocorticoid)?

Answer 38

Regulating extracellular sodium/potassium concentration

Question 39

What occurs in the body when there is too little glucose?

Answer 39

CNS dysfunction

Question 40

What occurs in the body when there is too much glucose?

Answer 40

Dehydration and microvascular damage (e.g. blindness)

Question 41

What is the ideal glucose value?

Answer 41

5.5mmol/L

Question 42

What is glycolysis?

Answer 42

Glucose --> pyruvate

Question 43

What is gluconeogenesis?

Answer 43

Pyruvate --> glucose

Question 44

What is the role of glucagon?

Answer 44

Mobilises fuel in the catabolic phase of glucose metabolism

Question 45

What is the role of insulin?

Answer 45

Stores fuel in the anabolic phase of glucose metabolism

Question 46

What is the receptor for insulin?

Answer 46

Receptor tyrosine kinase

Question 47

What is the overall effect of insulin?

Answer 47

Concentration of glucose, amino acids and fatty acids in the blood goes down

Question 48

What is the principle target tissue of glucagon?

Answer 48

Liver

Question 49

What is the overall effect of glucagon?

Answer 49

Increased glucose output via glycogenolysis and gluconeogenesis, and increased lipolysis

Question 50

What other molecule can be used as fuel when glucose is low?

Answer 50

Ketone bodies

Question 51

What are the 3 other regulators of blood glucose?

Answer 51

Growth hormone, glucocorticoids, adrenaline

Question 52

What 3 hormones are involved in daily calcium balance?

Answer 52

Parathyroid hormone, calcitonin, 1,25-DHCC (active vit D)

Question 53

Under what condition is parathyroid hormone released?

Answer 53

In response to falling levels of circulating calcium

Question 54

What is the effect of parathyroid hormone on bone?

Answer 54

Calcium release from calcium salts in bone ECF

Question 55

What is the effect of parathyroid hormone on the kidneys?

Answer 55

Increase tubular reabsorption of calcium

Question 56

What is the effect of parathyroid hormone on the gut?

Answer 56

Increased formation of active vitamin D causes enhanced absorption of calcium from intestine

Question 57

How is active vitamin D involved in long-term calcium homeostasis?

Answer 57

Acts to increase absorption of calcium from the intestine in order to protect bone

Question 58

When is calcitonin secreted?

Answer 58

In response to an elevation in blood calcium

Question 59

What is the overall effect of calcitonin?

Answer 59

Reduce blood calcium levels