Endocrinology

Question 1

What glands are included in the endocrine system?

Answer 1

• pituitary (anterior/posterior)
• pineal gland
• thyroid
• parathyroid
• endocrine pancreas
• adrenal

Question 2

What controls the release of hormones from the pituitary?

Answer 2

Inhibitory factors secreted by the hypothalamus

Question 3

What is secreted by the posterior pituitary?

Answer 3

oxycytocin + ADH

Question 4

What is the role of oxycytocin?

Answer 4

plays a role in social interaction, sexual reproduction, childbirth

Question 5

What are the cell types found in the anterior pituitary?

Answer 5

• somatotrophs
• lactotrophs
• corticotrophs
• gonadotrophs
• thyrotrophs

Question 6

What is the most common anterior pituitary cell type and what is its secretion?

Answer 6

Somatotrophs (50%)

secretes GH

Question 7

What do lactotrophs secrete?

Answer 7

Prolactin (lactation)

Question 8

What do thyrotrophs secrete?

Answer 8

Thyroid stimulating hormone (TSH)

Question 9

What do gonadotrophs secrete?

Answer 9

secrete gonadotrophins (e.g. leutinising hormone, follicle stimulating hormone)

Question 10

What are sustentacular cells?

Answer 10

support pituicytes or other cell types

found throughout body (e.g. sertoli cells)

Question 11

What might be an effect of a benign tumour of pituitary (pituitary adenoma)?

Answer 11

tumour will expand sella tusica, and press on the optic chiasm (causing loss of temporal visual field)

Question 12

Where is the pineal gland found?

Answer 12

below the posterior portion of the corpus callosum

Question 13

What is secreted by pinealocytes and what stimulates this?

Answer 13

secretes melatonin in response to autonomic stimulation

sometimes arranged in rosettes (several pinealocytes around central area with cell processes directed towards a central capillary)

Question 14

What makes the pineal gland easy to see on an X-ray?

Answer 14

calcium may accumulate (particularly with age) - brain sand

helps to locate midline of brain

Question 15

What is the structure of the thyroid gland?

Answer 15

consists of follicular epithelial cells (simple cuboidal) which secrete colloid into centre

Question 16

What is the cycle of follicular cell thyroxine production?

Answer 16

• when dormant, follicular cells secrete thyroglobulin and store it within colloid
• when active, follicular cells reabsorb and break down thyroglobulin and convert it into the active hormone
• active hormone secreted into blood
• when active, follicular cells become columnar (normally cuboidal)

Question 17

What cell type other than follicular cells are found in the thyroid gland?

Answer 17

C-cells

secrete calcitonin (antogonistic to parathormone secreted by parathyroid)

sit between follicles

Question 18

What cell types are found in the parathyroid glands?

Answer 18

• Chief cells
• oxyphil cells
• adipocytes

Question 19

What is the function of chief cells in the parathyroid?

Answer 19

secrete PTH (parathyroid hormone)

rasies serum calcium in bones, kidney, gut

mostly nucleus

Question 20

What cell types are found in the islets of langerhans of the pancreas?

Answer 20

• B-cells - insulin
• a-cells - glucagon
• D-cells - somatostatin
• PP cells - pancreatic polypeptide (digestion?)

Question 21

What hormone types do the parts of the adrenal glands produce?

Answer 21

outer cortex produces steroid hormones

inner medulla secretes adrenaline/noradrenaline

Question 22

What are the layers of the adrenal cortex?

Answer 22

• zona glomerulosa
  
  • outer, thin, incomplete layer
• zona fasciculata
  
  • middle, most prominent layer
• zona reticularis
  
  • inner layer

Question 23

What do the layers of the adrenal cortex secrete?

Answer 23

zona glomerulosa - mineralocorticoids (e.g. aldosterone)

zona fasciculata - glucocorticoids (e.g. cortisol)

zona reticularis - androgenic steroids (e.g. testosterone)

Question 24

Are hormones made in adrenal cortex stored?

Answer 24

No, once hormones are made, they are discharged into sinusoids between cells

some fats/cholesterol stored to help produce the hormones (gives macroscopic yellow appearance)

Question 25

What do cells in the adrenal medulla secrete and are these stored?

Answer 25

some cells secrete adrenaline (epinephrine)

some cells secrete noradrenaline (norepinephrine)

hormones are stored within neurosecretory granules within cells)

Question 26

What do atrial myocytes secrete?

Answer 26

Atrial Natureitic peptide

causes reduction in BP

• Increased renal Na⁺ absorption
• vasodilation
• increased vascular permeability