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27 Cards in this Set
- Front
- Back
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Types of hydrophilic hormones? |
Peptide hormones catecholamines |
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Types of lipophilic hormones? |
Steroid hormones Thyroid hormones |
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Definition for secretion |
Synthesis and release of a hormone
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What are the major endocrine glands |
Hypothamalus
Pituitary Thyroid Parathyroid Adrenal glands Pancreas Ovaries/testes |
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How do hydrophilic hormones pass through membrane? |
Extracellular receptors
May be: - direct resulting in depolarisation - Protein phosphorylation - G-protein coupling via second messenger |
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How do hormones pass into cells? |
Free hormones
Activation Dimers bind to DNA |
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How is a peptide hormone synthesised? |
Preprohormone synthesised Prohormone package Hormone stored Hormone and some pro fragments secreted |
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Compare the metabolism, half life, duration of peptide and steroid hormones |
Peptide - rapidly broken down
Steroid - slowly degraded Half life and duration - peptide mins, steroid hours |
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What influences hormone control? |
Other hormones, neurons, plasma levels of nutrient, metabolic inaction, excretion, plasma to plasma proteins |
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What connects the hypothamalus and the pituitary? |
Infundibulum - containing nerve fibres & blood vessels to allow communication between the areas |
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Another name for anterior pituitary? |
Adenohypophysis |
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Another name for posterior pituitary? |
neurohypophysis |
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Explain the connection between hypothalamus & pituitary |
Axons from 2 groups of hyp neurons pass down stalk - end in posterior Hyp and anterior connected by blood vessels Blood vessels - median eminence (hyp) recombine to hypothalamo-pituitary portal vessels. Short portal vessels - connect ant and post. |
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What is the secretion of each anterior pituitary hormone stimulated or inhibited by? |
Hypothalamic hypophysiotropic hormones
RH synthesised in hypo Neurons terminate in median eminence AP cause release of hormones in portal vessels - carried to anterior |
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What are the properties of hypothalami-releasing hormones? |
Secretion in pulses Transduced through Ca, cAMP and membrane phospholipid products Stimulates stored target in anterior, syn of target, modify activity through post-translational effects, hyperplasia, hypertropy |
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Major types of endocrine disorder |
Hyper/hypo secretion Hyper/ hypo responsiveness of target cells |
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Name the nerve tract connecting posterior love and hypothamalus? |
Hypothalamo-hypophysial nerve tract. |
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Where are hormones synthesised? |
Cell bodies of large neurons lying in supraoptic and paraventricular nuclei of the hypothalamus |
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Name two posterior hormones |
Oxytocin Vasopressin Nonapeptides with disulphide bridge linked aa 1 and 6 |
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How are hormones secreted from posterior? |
Synthesised in hypo
Packaged in granules with neurophysin - transport protein Granules transported down fibre to axon terminal in posterior Granules released. Contents diffuse into adjcaent capillaries. Secreted by Ca-dependent exocytosis Circulate as free hormones |
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What is oxytocin? |
Causes contraction of smooth muscle- uterus, myoepithelial cells lining mammary glands Positive feedback Ferguson reflex- uterus Mediated via IP3 Low circulating conc. |
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When is oxytocin elevated? |
Parturition, lactation and mating |
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What is the function of vasopressin? |
Control water excretion and regulates bp (vasoconstrictor)
Pressor agent - inc. in systemic bp. Acts on V1A receptors on smooth muscle - vasconstrictino via Ca & PLC 2nd messengers |
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What are the vasopressin receptors? |
V1 - all tissues, except kidnet, IP3
V2 - kidney, cAMP |
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What factors stimulate ADH release? |
Increase in op of blood Fall in ECV Decrease in arterial pO2/ inc. pCO2 |
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Name a vasopressin secretion disorder |
Overproduction of vasopressin (SIADH) - caused by brain disorders, results in water retention, hyponatraemia, v. high urine osmolality, Administer AVP |
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Name another vasopressin secretion disorder |
Undersecretion of vasopressin Damage or dysfunction of hypothalamus - DI Plasma osmolality increases Symptoms - polydipsia, polyuria Treatment - synthetic vasopressin |
