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19 Cards in this Set
- Front
- Back
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What 2 major systems are invovled in the coordination of physiological processes?
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-Central ervous system
-Endocrine system |
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How do cells that are not in contact with each other communicate?
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Through various chemical substances that are secreted by releasing cells and interact with specific receptors on distant receptors
=> This signalling leads to a specific physiological effect |
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What does endocrine signalling involve?
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Hormone secretion into the blood by an endocrine gland
-This hormone is transported to a distant target |
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Where does Neuroendocrine signalling start?
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-Starts with a stimulus in the hypothalamus
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What is paracrine signalling?
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Short distance signalling, can be from one cell to a different or similar cell
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What is autocrine signalling?
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Cell can communicate with itself (secretes a substanc that act uppon itself)
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What are the 6 steps that can be involvedin hormone communication?
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1) Synthesis: of hormone by endocrine gland (or neurons in case of neurohormone)
2) Release: of hormone by endocrine cell (or neurohormone by neuron) 3) Transport: of neuro/hormone to its target by the bloodstream 4) Detection: of neuro/hormone by a specific receptor ptn on the tarfet cells 5) Change in cell metabolism: triggered by the hormone-receptor interaction 6) Removal of the hormone: usually ends the cell response |
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What are the classical endocrine organs?
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-Brain: Hypothalamus and Anterior/Posterior Pituitaries
-Heart: ANP (Atrial Natriuretic Peptides) -Adrenal Glands: Cortex and Medulla -Pancreas: Islets of Langerham -Ovaries/Testis: Female/Male |
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What are the types of hormones?
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-Protein hormone: Glycoproteins and polypeptides
-Steroid Hormones: Aldosterone, cortisol, estradiol, progesterone, testosterone, vitamin D -Amine Hormones: Epinephrin, T3, T4, melatonin |
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What happens is a hormone is protein in nature?
How is such a hormone regulated? |
-A gene encodes that hormone
- Regulate parathyroid hormone by regulating the gene |
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How can a steroid or amine hormone be regulated?
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Regulating the amount of enzyme that makes the gene
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How are protein hormones synthesized?
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Preprohormones: synthesized on the ribosome
Prohormones: Made from preproH on the RER Golgi: prohormones pckged into secretory vesicles (proH -> hormone + other peptides) Vesicles: storage of hormones Corelease of hormone and other peptides |
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What are some examples of steroid hormones?
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-Cortisol
-Aldosterone -Testosterone: extra methyl gp -Estradiol: aromatic ring |
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What are some thyroid hormones?
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T3 (3 iodines)
T4 (4 Iodines) |
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What happens if you are iodine deficient?
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Thyroid deficient
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What does the lock and key theory describe?
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Intraction between a hormone and its receptor
Hormone fits exctly into its receptor (like a lock and key) |
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What are the properties of hormone receptors?
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-Specificity: recognize a single hormone or H family
-Affinity: High affinity for the H -Saturability: Should show saturability (have a finite number of receptors) -Measureable biological effect: can measure biological response due to interaction of H with its receptor |
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How can receptors be regulated?
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Upregulation: Inc receptor activity in response to H or receptor synthesis
Downregulation: Dec receptor activity or receptor synthesis |
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What are the 3 mechanisms by which a hormone can exert effect on target cells?
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1) Direct effects: on fct at cell mb
2) Intracellular effects: mediated by 2nd messenger system 3) Intracellular effects: mediated by genomic or nuclear action |
