BIOL10002 Lecture Notes - Pituitary Gland, Codocyte, Autocrine Signalling
Friday, March 23, 2018
BIOL10002 : Lectures 12 & 13 - Endocrine System &
Hormones
Key Concepts
-Hormones are molecular signals
-Hormones bind to receptors
-The pituitary gland links the endocrine and nervous system
-Hormones regulate mammalian physiological systems
Molecular Signals
-Hormones are molecular signal released by specific cell types and influence other
cells
-Cells communicate with each other to maintain stable internal environment
-Target cell — Cell that has a receptor specific for a specific hormone
-Receptor — Molecule that the hormone binds to and initiates a response hen
-RECAP: Hormones are secreted into the interstitial fluid, ass into the blood then travel
to target cell.
•Paracrine signal : Hormone that bind to the receptor of a cell that is nearby
•Autocrine Action : Hormone binds to itself — self-regulation
Hormones
-Peptides/Proteins
•Synthesized then held in secretory vesicles, until secreted by exocytosis
(vesicles fuses with the cell membrane, then the contents are released into the
interstitial fluid/blood)
•Water soluble ; easily transported in blood
•Only binds to membrane-bound receptors (non-lipid soluble)
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Friday, March 23, 2018
-Steroid Hormones
•Synthesis from steroid cholesterol
•Lipid soluble - can pass through cell membranes — not stored in vesicles
•Diffuse out of cells and are bound to carrier molecules in blood
•Limited synthesis, only produced when needed ; Binding proteins/ chaperones
bring it to its target cell
•Acting on the nucleus — need to regulate many genes
•Increasing / Decreasing transcription of several genes
-Amines
•Mostly synthesized from tyrosine (amino acid)
-Receptor is always on the nucleus
•Can be water-soluble or lipid soluble so mode of action differs
Glands
-Exocrine
•Epithelial connective tissue, but store enzymes (pancreas, gall bladder,
salivary gland)
•Exocrine glands secrete their products via ducts
-Endocrine
•Collection of cells that secrete hormones into blood
•pineal, thyroid gland, parathyroid gland, adrenal gland, Gonads, thymus,
pituitary
-target cells of hormones released from the pituitary
•MAIN: Thyrotropin Stimulating Hormone (TSH) — Thyroid gland (target tissue)
-Anterior Pituitary Gland
-ADRENAL GLAND
•Adrenal Medulla(Nervous control)— Outer cortex: Cortisol, aldosterone
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Document Summary
Biol10002 : lectures 12 & 13 - endocrine system & The pituitary gland links the endocrine and nervous system. Hormones are molecular signal released by speci c cell types and in uence other cells. Cells communicate with each other to maintain stable internal environment. Target cell cell that has a receptor speci c for a speci c hormone. Receptor molecule that the hormone binds to and initiates a response hen. Amines: mostly synthesized from tyrosine (amino acid) Receptor is always on the nucleus: can be water-soluble or lipid soluble so mode of action differs. Exocrine: epithelial connective tissue, but store enzymes (pancreas, gall bladder, salivary gland, exocrine glands secrete their products via ducts. Endocrine: collection of cells that secrete hormones into blood, pineal, thyroid gland, parathyroid gland, adrenal gland, gonads, thymus, pituitary. Target cells of hormones released from the pituitary: main: thyrotropin stimulating hormone (tsh) thyroid gland (target tissue) Adrenal gland: adrenal medulla(nervous control) outer cortex: cortisol, aldosterone.
