Endocrinology

Question 1

What are hormones

Answer 1

Secretory product of ductless (endo) glands released directly into circulation in small amounts in response to a specific stimulus .
On delivery in circln produce response on target cells

Question 2

Classification of hormones based on chemical nature

Answer 2

Peptide
Steroid
Thyroid and biogenic amines

Question 3

Examples of peptide hormones

Answer 3

Ant & post pituitary hormones
Insulin
Glucagon
PTH
PDGF

Question 4

Thyroid & Biogenic amine hormones examples

Answer 4

Thyroid hormones
Adrenaline
Histamine
Bradykinin
Serotonin

Question 5

Depending on mechanism of action

Answer 5

Group 1 :Intracellular receptor
Eg: steroid , thyroid
Group 2 : cell membrane receptors (2° messengers )

Question 6

Different mechanisms of hormone action after combining with receptors

Answer 6

*altering permeability of the cell membrane
*activating the intracellular enzyme
*Through effect on gene expression
* through tyrosine kinase activation

Question 7

Action of hormones through change in membrane permeability

Answer 7

1.Hormone binds with receptor (cell membrane ).
2. Conformational changes cause opening/ closing of ion channels
Eg ; Adrenaline,
Nor adrenaline

Question 8

Action thro secondary messengers which activate intracellular enzyme

Answer 8

The hormone, which acts on a target cell is called first messenger.
Form hormone receptor complex
In turn activate enzymes of cell , cause formation of another substance = 2° messenger ( cAMP , IP3 , DAG )

Question 9

The release of second messenger is mediated by

Answer 9

GTP binding proteins or G proteins