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Flashcards by aoifemcdougall, updated more than 1 year ago
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Created by aoifemcdougall
about 11 years ago
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| Question | Answer |
| What hormones influence growth? | Thyroid hormones Growth hormone Oestrogen + testosterone Insulin, cortisol + vit. D and PTH |
| What are the functions of thyroid hormones? | Needed for protein synthesis in brain of infant and infant Require for normal development of neurons Neccessary for childhood growth |
| What are the symptoms of hypothyroidism? | Sparse hair, large tongue, permanent mental impairments |
| What are the metabolic effects on growth hormone? | Increase blood glucose levels Increase liplysis (fatty acids for energy production) Facilitates uptake of amino acids for protein synthesis |
| In what periods of growth are the effects of growth hormone most effective? | Postnatal, infancy and adolescence |
| When does growth in length of bone stop? | Until growth centres close (epiphyses) |
| What are sex hormones responsible for? | Pubertal growth spurt |
| What are sex hormones mediated by? | Secretion of GH and IGF-1 |
| What are the effects of sex hormones? | Stimulate bone growth but also accelerate closure of growth plates Testosterone-anabolic effect on protein synthesis |
| How does insulin contribute to growth? | Promotes foetal growth Promotes post natal growth by stimulating secretion of IGF-1 |
| What hormone inhibits growth if it is at a higher than normal level? What are its effects? | Cortisol Increases bone resorption |
| How to PTH and vitamin contribute to growth? | Ensures adequate amount of Ca2+ and PO4 levels for bone formation. PTH increase ca2+ Vitamin D increases absorption of Ca2+ in gut |
| What are the effect of excess growth hormone in: Childhood Adults | Childhood-Accelerates normal growth (gigantism) Adults: Appositional growth (vertical) not possible. Acromegaly occurs |
| What is acromegaly? | A disorder caused by excess GH in adulthood causing increase in bulk of hands, feet and jaw |
| What is calcitonin released in response to? | High [Ca2+] plasma levels |
| What effect does calcitonin have? | Increases bone formation Decreases reabsorption in kidneys |
| What hormones affect bone? | PTH, Calcitonin Growth Hormone IGF-1 Insulin, Cortisol Oestrogen and Testosterone |
| Describe osteoclasts. | Large, multinucleate cells that resorb bone Found in howship's lacunae |
| What cells synthesise and secrete collagen fibres forming a matrix (later mineralised by calcium salts) | Osteoblasts |
| What are osteocytes? | Osteoblasts trapped in bone matrix |
| What do low [Ca2+] cause? | Increase in nerve excitability, therefore muscle spasms |
| What is a disorder causes by vitamin D deficiency and what are the symtpoms? | Rickets (children) Osteomalacia (adults) Result is 'soft', weak bones due to undermineralised bone |
| What is a cause of hypoparathyroidism? | Defective mineralisation of teeth |
| What are the functions of calcium? | Action potentials (in cardiac muscle) Membrane excitability Excitation-contraction coupling (muscle) Blood clotting |
| What are the hormones involved in calcium homeostasis? | Parathyroid hormone Calcitonin Vitamin D |
| What is parathyroid hormone released in response to? | Low [Ca2+] plasma |
| What are the effects of parathyroid hormone? | Increases bone resorption Increases Ca2+ reabsorption in kidneys (with decreased PO4 resorption) Increases uptake of Ca2+ from the intestines (assisted by vitamin D) |
| What do baroreceptors detect? | Blood pressure (aterial distension) |
| What do baroreceptors do in response to low blood pressure? | Decrease firing of action potentials |
| What does the decrease in baroreceptor AP firing cause? | Increase in sympathetic nerve activity to restore blood pressure |
| How do medium term responses restore blood volume? | Shift interstitial fluid back into blood Decreasing fluid loss in kidneys (ADH + aldosterone) |
| What promotes release of ANH? | Increase in plasma volume Increase in atrial distension |
| What are the two disorders of ADH secretion and give the outcome of each. | Hypo-secretion - diabetes insipidus (large volumes of urine) Hypersecretion-syndrome of inappropriate ADH (SIADH) Causes water retention. |
| What is the effect of K+ on nerve? | Causes depolarisation which causes axons to fire AP |
| What effect does increasing [ECF] K+ levels have on nerve? | Causes deoplarisation but maximum potential does not return to 'resting' levels Axon remains in an extended refractory period |
| How do K+ salts claim to desensitise 'hypersensitive dentine'? | K+ can travel along dentine tubules to nerves Nerves become depolarised and Na+ channels deactivated causing a prolonged refractory period |
| How does the rate of glomelular filtration respond to decrease in blood fluid volume | The rate of glomerular filtration decreases |
| What hormone promotes thirst? | Angiotensin II |
| Where are plasma proteins released and how long does this process take? | Released from liver. Takes 3-4 days |
| What are the two things in long term response that are needed in order to replace blood constituents | - Produce plasma proteins - Replace RBC |
| What hormone controls the production of red blood cells (erythopoiesis)? | Erythopoietin |
| Where is erythopoietin released from? | Kidneys by interstitial fibroblasts |
| What does the kidney release erythopoietin in response to? | Decrease in oxygen delivery |
| What organ does erythropoietin affect? | Red bone marrow |
| What is shock? | Inadequate blood flow to tissues |
| What is shock associated with? | Low cardiac output Low blood or ECF volume |
| What is hypovolaemic shock? | Decrease in ECF volume due to haemorrhage, sweating, diarrhoea or burns etc |
| What is a type of low resistance (distributive) shock? | Anaphylactic shock |
| What causes low resistance (distributive) shock? | Decrease peripheral resistance due to widespread vasodilation |
| What is cardiogenic shock? | When the heart fails as a pump |
| What does the effect of stress depend on? | Duration and severity of stress Effectiveness of any response |
| What are the three stages of the General Adaptation Syndrome? | Alarm reaction Resistance phase Exhaustion pahse |
| What are the two hormones involved in stress? | Adrenaline Glucocortisoids (eg. cortisol) |
| What does adrenaline to the effect of the sympathetic ns response? | Augments and prolongs the effect |
| Where is adrenaline stored and released? | Adrenal medulla |
| What effect does stress have on the sympathetic nervous system? | Increase in cardio output (CO) Redistribution of CO [flow to muscle increased, flow to gut decreased] Glycogen breakdown + stim. adrenaline release |
| Where are glucocorticoids released? | Adrenal cortex |
| Have hormone may have harmful effects if secretion is persistently high? | Cortisol |
| What are the effects of cortisol? | Increased energy production from glucose, amino acids and fats + increased protein breakdown Anti-inflammatory and immunosuppressive |
| How does cortisol possess an anti-inflammatory and immunosuppressant actions? | They inhibit the release of leukotrienes and prostaglandins and inhibit macrophages and helper T cells |
| What are the four physiological responses to blood loss and their function? | Immediate (stop bleeding) Short term (restore BP) Medium term (restor fluid volume) Long term (restore blood constituents) |
| What are the three responses of the immediate response to stop bleeding? | Vascular response Platelet response Coagulation response |
| What are the effects of the vascular response? | Smooth muscle: spasm due to trauma Vasoconstriction Endothelium: Platelet adhesion and aggregration |
| What is the process of the platelet response? | Platelets adhere to endothelium wall and aggregate (clump together) Release chemicals to cause further aggregation. Forms platelet plug |
| What does corticosteroid treatment suppress? | The release of ACTH and CRH |
| What enzyme catalyses the conversion of fibrinogen to fibrin? | Thrombin |
| The effects of stress are greater when: | Standing Anxious patients With complex procedures |
| What vitamin is needed for the synthesis of several clotting factors? | Vitamin K |
| What two pathways activate the coagulation pathway? | Intrinsic and extrinsic pathway |
| What activates the intrinsic pathway in plasma response? | Vascular damage |
| What activates the extrinsic pathway of the plasma response? | Tissue damage |
| What enzyme is needed to break down fibrin in soluble fibrin fragments? | Plasmin |
| What should happen to stress response in a healthy individual with persistent exposure to the stressor? | The response will diminish |
| What are the effects if individual's adaptation to stress fails? | Adrenal failure Immunosuppression |
| What is the function of the glomerulus? | Filtration |
| What is the function of the proximal convoluted tubule? | Reabsorption and secretion |
| What is the function of the distal convoluted tubule? | Reabsoprtion and secretion |
| What is the function of the loop of henle? | Counter-current multiplier |
| What is the function of the collecting ducts? | To concentrate urine |
| What are the three vasculate structures of the glomerulus? | Afferent arteriole > glomerular capillaries > efferent aterioles |
| What pressure favours filtration in the glomerulus? | Capillary hydrostatic pressure |
| What pressure opposes the filtration in the glomerulus? | Plasma protein ocontic pressure Capsular pressure |
| How is the net filtration pressure (EFP) calculated? | Capillary hydrostatic pressure - (capsular + oncotic pressure) |
| How much (as %) does the proximal tubule reabsorb of the glomerular filtrate? | 60-70% |
| What sort of molecules are absorbed by the proximal convoluted tubule? | Ions and small organic molecules |
| What hormone controls the reabsorption of water in the distal convoluted tubule? | ADH |
| What does ADH effect the reabsorption of water in the collecting ducts? | Creates aquaporin channels for water to pass through |
| What is the acending limb of the loop of henle permeable to? | Permeable to salts but not water |
| What is the descending limb of the loop of henle permeable to? | Water but not salts |
| What needs to move first in order for water to follow in the kindeys? | Na+ |
| What promotes the secretion of ADH | Decreased plasma volume Increased plasma osmolarity |
| What does the renin-angiotensin-aldosterone system promote? | Reabsoprtion of Na+ |
| In order for the reabsorption of Na+ in the distal convoluted tubule what ions need to be exchanged? | K+ and H+ |
| What hormone promotes the release of aldosterone? | Angiotensin II |
| What enzyme convert angiotensinogen to angiotensin I? | Renin |
| What does atrial natriuretic hormone promote? | Increases excretion of Na+ (water) [Opposite effects to aldosterone] |
| What hormones are produced by the islets of langerhans and which specific cells are responsible for the production of each one? | Insulin (Beta cells) Glucagon (Alpa cells) Somatostatin (Delta cells) |
| What is insulin released in response to? | Raised glucose blood levels Raised amino acid levels |
| What is the function of insulin? | Increases levels of protein synthesis enzymes Facilitates glucose entry to cells Increases uptake of amino acid into cells |
| What does insulin promote the formation of? | Glycogen Triglycerides Proteins |
| What are the three classifications of hormones? | Steroid Non-steroid - amino acid derivatives - peptides - glycoproteins |
| What does insulin promote the formation of? | Glycogen Triglycerides Proteins |
| What nerve activity promotes the secretion of insulin? | Vagus nerve (CNX) |
| What are the two sub-groups of non-steroid peptide hormones and give an example for each. | Short chain: ADH Long chain: Calcitonin GH PTH Insulin and glucagon |
| What hormones inhibit the secretion of insulin? | Adrenaline |
| What is glucagon released in response to? | Low blood glucose levels High amino acid levels |
| How are peptide hormones usually produced? | In an inactive form (Preprohormone) which is processed in ER to become a prohormone and is then packaged by GolgiA to produce the hormone |
| What does glucagon promote? | Glycogenlysis in liver Gluconeogenesis in liver Lipolysis Ketone synthesis |
| What is an example of a steroid hormone? | Aldosterone Oestrogen Testosterone Cortisol |
| Give an example of non-steroidal amino acid derivate hormones? | ADH oxytocin somatostatin |
| What is glycogenlysis? | Breakdown of glycogen to glucose |
| How are hormones transported? | In the blood stream |
| What is gluconeogenesis? | The production of glucose from non-carbohydrate subtrates |
| What inhibits the secretion of glucagon? | Insulin Somatostatin |
| What hormone inhibits the secretion of both glucagon and insulin? | Somatostatin |
| What is a second messenger system? | Hormones that cannot pass through cell membrane bind to target cell receptors which when activated start a cascade of reactions |
| Where do steroid hormones bind to their receptors? | Inside the cell |
| Describe the action of hormones in general. | Synthesis/storage of hormone Released in respone to stimuli Transport via bloodstream Action on target cells and metabolised by liver or excreted by kidneys |
| What carriers steroid hormones in the blood? | Plasma proteins |
| What does the stimulation of a steroid hormone and its target cell receptor produce? | mRNA and therefore ultimately a protein |
| How do non-steroid hormones work? | Bind to receptor proteins which activates G-protein. G-protein causes a reaction to produce a second messenger |
| What increases the sensitivity of a target cell to a hormone? | The number of receptors present |
| What is the term to describe the increase and decrease in hormone receptors? | up (increase) and down (decrease) regulation |
| How do hormones from the hypothalamus travel to the posterior pituitary gland? | Via nerve axons |
| How are hormones produced in the hypothalamus passed to the anterior pituitary gland? | Via blood vessels (hypothalamic-pituitary portal vessels) |
| What are the hypothalamic hormones? | CorticotrophinReleasingHormone(CRH) GonadotrophinReleasingHormone(GRH) Throtropin releasing hormone (TRH) Prolactin releasing hormone (PLRL) Somatostatin and dopamine |
| What are the anterior pituitary hormones? | FSH, LH, GH,TSH, ACTH, PL |
| What hormone is released by the adrenal cortex? | Cortisol |
| What is the effect of FSH? | Ovum maturation Sperm production |
| What is the effect of LH? | Testosterone production Production of oestrogen |
| What hormone affects the thyroid to make it release thyroid hormones? | Thyroid Stimulating Hormone (TSH) |
| What two hormones affect the release of Growth hormone from the anterior pituitary gland? | GHRH and Somatostatin (GHIH) |
| What are the effects of the release of prolactin? | Breast development and milk production |
| What are the two hormones released by the posterior pituitary gland? | ADH Oxytocin |
| What does the hypothalamus control? | Thermoregulation Hormone secretion Circardian rhythms Emotions |
| What is negative feedback? | The end-product produced by a hormone inhibits the action of the hypothalamus |
| How is ADH transported to kindeys? | In the blood plasma |
| What is the function of ADH? | Increases water reabsorption in collecting ducts |
| What is the effect of oxytocin? | Contraction of uterus (by stretch of uterus) Milk ejection (induced by infant suckling) |
| Name the other endocrine glands (exclud. hypothalamus and PT and AT) | Thyroid gland Parathyroid glands Pancreas (islets of langerhans) Adrenal Glands Gonads (ovaries; testes) + placenta |
| What hormones are released by the thyroid gland? | T3 (thyroxin) T4 (tetra-iodo-thyroxine) Calcitonin Thyroid hormones |
| What cells produce calcitonin in thyroid gland? | Para-follicular C cells |
| What is the effect of T3? | Increases metabolic rate Determines basal metabolic rate |
| What is T3 essential for? | Normal growth in fetal period and childhood |
| What are disorders caused by under secretion of thyroid hormones? | Hypothyroidism Myxoedema Cretinism |
| What disorders are caused by the oversecretion of thyroid hormones? | Hyperthyoidism Grave's disease |
| What hormone is produce by the parathyroid gland? | Parathyroid hormone |
| What is the function of the parathyroid hormone? | Involved in regulating blood calcium levels |
| What do the islets of lslets of Langerhans look like at a histological level? | Pale purple circles |
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