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Question 1

What are the principal endocrine glands?

Answer 1

Hypothalamus
Pituitary gland
Thyroid gland
Parathyroid gland
Islets of pancreas
Adrenal gland
Gonads-testis and ovaries

Question 2

What are other organs with endocrine functions?

Answer 2

Heart- ANP
Kidney- 1,25 dihydrocholecalciferol, erythropoietin
Live- 25 hydrocholecalciferol & somatomedins
Pineal gland- melatonin
Skin- calciferol
GIT-ghrelin gastrin, secretin, vasoactive intestinal peptide

Question 3

What are the 4 trophic hormones of the anterior pituitary?

Answer 3

The four anterior pituitary tropic hormones are
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Thyroid-stimulating hormone (TSH)
Adrenocorticotropic hormone (ACTH)

FLAT PG

Question 4

What is the structure where hormones of the hypothalamus are released?

Answer 4

Median eminence

Question 5

What are the two general classifications of hormones?

Answer 5

Local hormone- which have specific local effect e.g., secretin and cholecystokinin

General hormone- which affect almost all tissues of the body e.g., thyroid hormone, growth hormone

Question 6

What are the chemical classification of hormones?

Answer 6

Classified into 3 groups:

1. Steroid hormone (Derived from cholestrol) Ex: Progestrone and teststorone
2. Polypeptide/Protein hormone: Polypeptides- Hypothalamic hormones, posterior pituitary hormones, parathyroid hormone, calcitonin, insulin etc.
3. Derivatives amino acid Tyrosine e.g., Thyroid hormone, adrenal medullary hormones

Question 7

What are the 3 locations where hormone receptors can be found?

Answer 7

1. Membrane receptors: Protein, peptide, catecholamine
2. In the cell cytoplasm: Steroid hormones
3. In the cell nucleus: Thyroid hormone

Question 8

What are the steps of a protein/peptide/catecholemine hormones to elicit an action inside the cell.

Answer 8

Summary: protein/peptide/catecholemine hormones cannot freely pass through the plasma membrane and therefore need a plasma membrane receptor which has a secondary messenger inside the cell.

Mechanisim:

The hormone binds to the membrane receptor. The membrane receptor then changes shape and binds to G protein which activates it.

The G protein then binds to GTP and releases GDP to get activated

The activated G protein then binds to adenylate cyclase in the membrane which converts ATP to cAMP

cAMP is the second messenger

cAMP can elicit actions on different protein kinases inside the cell