1. Presented by Ena Athaide
MSc -1,Sem-2
Institute of Science, Mumbai
2. oAnimals have two systems of
internal communication and
regulation:
•The nervous system
•The endocrine system
3. o The Nervous system conveys high-speed
electrical signals along specialized units
called Neurons.
o The Endocrine system, made up of endocrine
glands, secretes hormones that coordinate
slower but longer-acting responses to stimuli.
4.
5. o A Hormone is a chemical signal that is
secreted into the circulatory system and
communicates regulatory messages
within the body.
o Hormones may reach all parts of the
body, but only certain types of cells,
target cells, are equipped to respond.
6. o Signaling by any of these molecules involves
three key events
-Reception
-Signal transduction
-Response
7. o Steroids
o Non steroid
-Protein and polypeptides
-Tyrosine-derived
-Eicosanoids
-Vitamins
8. o Steroid Hormones:
-Lipid soluble
-Diffuse through cell membranes
-Endocrine organs
-Adrenal cortex
-Ovaries
-Testes
-Placenta
9. o Non-steroid Hormones:
-Not lipid soluble
-Received by receptors external to the cell
membrane
-Endocrine organs
-Thyroid gland
-Parathyroid gland
-Adrenal medulla
-Pituitary gland
-Pancreas
10.
11. o Group 1 Hormones- binds to Intracellular
receptors, to form receptor complexes,
mediate biochemical functions. Mostly
lipophilic in nature.
o Group 2 Hormones- binds to cell surface
receptors and stimulate the release of
secondary messengers which in turn perform
biochemical functions.Thus, hormones itself
is the first messengers.
12. o Group 2 hormones are subdivided into three
categories based on chemical nature of the
second messenger .i.e. cAMP and
phosphatidylinositol/calcium ,
o Some cases second messenger is unknown.
