Endocrinology
Terms
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- Father of Endocrinology
- Claude Bernard
- Hormones
- Chemical messengers secreted into bloodstream stimulates response in another tissue or organ
- Target Cells
- have receptors for hormone
- Endocrine Glands
- produce hormones
- Endocrine System
- includes hormone producing cells in organs such as brain, heart and small intestine.
- Neuroendocrinology
- the study of the combined function of the nerves and glands that release Hormones in the body
- Nervous System
- evolved for responding to rapid changes in the environment and for precise control over specific tissues
- Exocrine Glands
- glands whose secretions pass into a system of ducts that lead ultimately to the exterior of the body.
- Examples of Exocrine Glands
-
Salivary
Liver (bile producing glands)
Gastric Glands
Sweat Glands
Prostate Glands - Why is a Cell a Target?
- because it has a specific receptor for the hormone
- Endocrine
- born via bloodstream act on distant site
- Paracine
- acting on local env., act on adjacent cells
- Autocrine
- acting on cell that secreted them
- Intracine
- acting within the cell that produces them
- Neurocrine
- Neutral cells that release chemical signals into the bloodstream
- Amino Hormones
- derived from tyrosine
- Eicosanoids
- derived from FFA's
- Peptide and Protein hormones
- encoded in genes
- steriod hormones
- derived from cholesterol
- Amino Hormones (General)
-
derived from tyrosine
includes catecholamines Ep and Nor-Ep (water sol)
includes T4 and T3 (lipid Sol) - Eicosanoids (General)
-
derived from FFA's
inc. Prostaglandins, Prostacyclins, Leukotrienes and Thromboxanes
Archodonic acid is the most abundant precurser of these hormones - Protein and Polypeptide Hormones (General)
-
range from 3 - hundreds of amino acids
water soluble
comprise largest number of hormones - Peptide Hormone Synthesis
-
1) synth as prepohormones in ribosomes and processed to prohormones in ER
2)Golgi Ap. packaged in to vesicles
3) released into extra-C- space in response to influx of Ca++ - Actions of Hormones
-
- some attach to protein receptor on membrane
- others enter cell directly on DNA
- in both enzymes are getting turned off - Hormone Receptors
- Proteins within cells targeted for activity that combine with the hormone and initiate the expressor of a specific gene
- Receptors for Water Soluble
- Found on surface of target cell, on the plasma membrane
- Receptors for Fat Soluble
- Reside in the Nucleus of the target cell (sometimes cytoplasm)
-
Hormone - Class - Location
Amine (Epinephrine) -
Class - Water Sol.
Location - Cell Surface -
Hormone - Class - Location
Amine (Thyroid Hormone) -
Lipid Soluble
Intracellular -
Hormone - Class - Location
Peptide/ Protein -
Water Soluble
Cell Surface -
Hormone - Class - Location
Steroids and Vit. D -
Lipid Soluble
Intracellular - 3 Stages of Cell Signaling
-
1) Reception
2) Transduction
3) Response -
Cell Surface Receptors
Location?
Principle Mech of Action? -
- Cell Surface Receptors
- Generation of 2nd messengers which alter the activity of other molecules usually enz. within the cell
- Intracellular Receptors
- Alter transcriptional activity of responsive genes - Types of Second Messengers
-
cAMP or gAMP
- activates converstion of ATP
Phospholipase C
- causes inositol triphosphate and diacyglycerol to be formed
Calcium
- activate calmodium - Control of Endocrine Activity
-
Rate of Production
Rate of Delivery
Rate of Degradation and Elimination