Endocrine Physiology

Question 1

Anterior pituitary gland

Answer 1

2/3 of the gland
Epithelial origin
Connected to the hypothalamus via capillary portal system

Question 2

Posterior pituitary gland

Answer 2

1/3 of the gland

Neural tissue origin

Question 3

What hormones does the anterior pituitary release?

Answer 3

Thyroid stimulating hormone (TSH)
Adrenocorticotrophic hormone (ACTH)
Follicle stimulating hormone (FH)
Lutenising hormone (LH)
Growth hormone (GH)
Prolactin

Question 4

What hormones does the posterior pituitary release?

Answer 4

Oxytocin
Antidiuretic hormone (ADH)

Question 5

The thyroid axis

Answer 5

Hypothalamus releases thyrotropin-releasing hormone (TRH)
This stimulates the anterior pituitary to release thyroid stimulating hormone (TSH)
This stimulates the thyroid gland to release triiodothyronine (T3) and thyroxine (T4)
Negative feedback

Question 6

The adrenal axis

Answer 6

Hypothalamus releases corticotrophin releasing hormone (CRH)
This stimulates the ant pituitary to release adrenocorticotrophic hormone (ACTH)
This stimulates the adrenal gland to release cortisol
Negative feedback

Question 7

What is the function of cortisol?

Answer 7

Inhibits the immune system
Inhibits bone formation
Raises blood glucose
Increases metabolism
Increases alertness

Question 8

Growth hormone axis

Answer 8

Hypothalamus releases growth hormone releasing hormone
This stimulates the ant pituitary to release growth hormone
Growth hormone stimulates the release of insulin like growth factor 1 (IGF-1) from the liver

Question 9

What is the function of growth hormone?

Answer 9

Stimulates muscle growth
Increases bone density and strength
Stimulates cell regeneration and reproduction
Stimulates growth of internal organs

Question 10

Parathyroid axis

Answer 10

Parathyroid hormone (PTH) is released from the parathyroid glands when there’s low Ca or high P
Its role is to increase serum Ca by:
Increases activity/number of osteoclasts - reabsorption of Ca from bone into blood increasing Ca concentration in serum
Increase in Ca reabsorption from kidneys - less Ca excreted in urine
Stimulates kidneys to convert vit D3 into calcitriol (active vit D) that promotes Ca absorption from food in the small intestine
Negative feedback

Question 11

What are the two parts of the pancreas?

Answer 11

99% exocrine

1% endocrine

Question 12

Endocrine pancreas

Answer 12

Alpha cells produce glucagon
Beta cells produce insulin
Delta cells produce somatostatin
F cells produce pancreatic polypeptide

Question 13

What are the two types of cells in the thyroid gland?

Answer 13

C (clear) cells

Follicles

Question 14

What do clear (C) cells in the thyroid make?

Answer 14

Calcitonin

Question 15

What do follicular cells in the thyroid make?

Answer 15

Thyroid hormone

Question 16

What are the parts of the adrenal cortex?

Answer 16

Outside in - GFR
Zona glomerulosa
Zona fasciculata
Zona reticularis

Question 17

What do the different parts of the adrenal cortex secrete?

Answer 17

Outside in - GFR medulla
Zona glomerulosa - aldosterone
Zona fasciculata - glucocorticoids
Zona reticularis - sex hormones
Medulla - catecholamines