Endocrinology Prof. K. Sivapalan. Jan. 2014Endocrine- general.2 Communication Between Cells Nervous....
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Transcript of Endocrinology Prof. K. Sivapalan. Jan. 2014Endocrine- general.2 Communication Between Cells Nervous....
Endocrinology
Prof. K. Sivapalan
Jan. 2014 Endocrine- general. 2
Communication Between Cells
• Nervous.• Humeral
– Metabolites.– Paracrine.– Endocrine.
Jan. 2014 Endocrine- general. 3
Definition.
• Endocrine:– Gland that secretes hormones.
• Hormone:– Secreted into blood and act on distant target organs-
insuilin, thyroxine, etc.• Conventional endocrine glands are pancreas,
thyroid, parathyroid, pituitary, adrenal and gonads.
• Liver, heart, lymphnodes and many other organs are now known to secrete substances with distant activity.
Jan. 2014 Endocrine- general. 4
Functions of Endocrine System
• Maintaining the internal environment.• Respond to emergency demands.• Integration of growth and development.• Reproduction.• One function- several hormones.• One hormone- several functions.
Jan. 2014 Endocrine- general. 5
Neuro - Endocrine Integration.
• Neurons with endocrine function- – hypothalamus, posterior pituitary.
• Neural control of endocrine function- – Parathyroid gland.– Pancreas.
• Combined action of nervous system and endocrine system-– Maintenance of blood pressure.
Jan. 2014 Endocrine- general. 6
Regulation of Endocrine Secretion.
• Change in circulating metabolite.• Change in tropic hormone.• Nervous control.
Jan. 2014 Endocrine- general. 7
Feed Back Regulation.
metabolite.
Secretion of hormone.
Response.
Negative feed back.
+
-+
Positive Feed Back +
Jan. 2014 Endocrine- general. 8
Transport of Hormones
• Water soluble hormones are dissolved in plasma.– Peptide hormones and catecholamines.
• Fat soluible hormones are bound to proteins.– Steroids.
• Thyroxine both ways.
Jan. 2014 Endocrine- general. 9
Blood Level of Hormones.
• Increased by secretion.• Decreased by,
– Metabolic destruction by tissues.– Binding with receptors in tissues.– Excretion by liver.– Excretion by kidneys.
Jan. 2014 Endocrine- general. 10
Mechanism of Action of Hormones.
• Binding with specific receptors in trget cells.• The receptor brings about several changes in
the activity of the cell• Location of Receptors-
– Cell membrane- for proteins, peptides and catecholamines.
– Cytoplasm- for steroids.– Nucleus- thyroid hormones.
• Down regulation and up regulation of receptor numbers are also ways of feed back regulation.
Jan. 2014 Endocrine- general. 11
Learn About Each Hormone,
• Source.• Latent period and Half life .• Regulation of secretion and removal• Mechanism of action• Physiological actions.• Consequences of excess and
insufficiency.• Function tests and assessment.