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30 Cards in this Set
- Front
- Back
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Cholecalciferol(Vit D3) is formed in the skin in response to ultraviolet light. TRUE/FALSE`
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TRUE.
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What is Vit. D3 eventually converted to?
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It is converted in the liver to 25-hydroxycholecalciferol, which is converted in the kidney to the active form of vit. D, 1,25-hydroxycholecalciferol.
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What is the structure of Vit. D?
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It is steroid in nature.
Its levels increase through dietary intake and through exposure to ultraviolet light. |
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Does PTH play a role with Vit. D?
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PTH is necessary for the conversion in the kidney of 25-hydroxycholecalciferol to 1,25 hydroxycholecalciferol.
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What is the function of Vit D?
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It promotes the absorption of calcium from the intestines and kidneys. In large amounts, vit D promotes absorption of calcium from bone to blood, but in minute amounts vit. D promotes bone calcification.
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What is typical in Vit. deficiency?
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causes hypocalcemia and hypophosphatemia with resultant rickets, or osteomalacia(bone softening in adults. In both of these there is impaired mineralization.
Osteoporosis is when there is a reduction in bone mass as a whole, rather than select reduction of the mineral content. |
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What is calcitonin?
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Known also as thyrocalcitonin, its origen is from C cells of the thyroid, and its structure is peptide. Increased blood calcium increases its secretion.
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What is the function of Calcitonin?
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Its effect is opposite that of PTH. It decreases plasma calciuym, and acts on bone by decreasing the activity of osteoclasts.
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What is the structure and origen of epinephrine?
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It originates in the adrenal medulla.
It is a derivative of tyrosine, and regulated by neural input to adrenal medulla. |
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What is the function of epinephrine?
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Epinephrine and norepinephrine, stimulate glycogen breakdown, lipid breakdown and gluconeogenesis.
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What is the function of epinephrine?
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Epinephrine and norepinephrine, stimulate glycogen breakdown, lipid breakdown and gluconeogenesis.
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Where is Norepinephrine found?
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It is present in sympathetic nerve endings. It has general vasoconstrictive effects, by interacting with blood vessel alpha-1 receptors.
Epi constricts as well, but not in all places. Epi constricts at alpha-1 receptors, but vasodilates at blood vessel beta-2 receptors, especially in skeletal muscle and heart, facilitating blood perfusion during a fight or flight response. |
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The adrenal medulla produces more epinephrine than norepi. TRUE/FALSE
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TRUE. Norepi is a neurotransmitter in postganglionic axons of the sympathetic nervous system where it mediates catabolic responses.
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What are glucocorticoids?
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Their origen is from the adrenal cortex. Structure is steroidal, and its secretion is stimulated by ACTH.
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What is the function of glucocorticoids?
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They mobilize carbohydrates, lipids and proteins during periods of stress, by elevating blood glucose, fatty acids and amino acids. It does so in part by stimulating gluconeogenesis in the liver.
It promotes breakdown of fats in adipose tissue to energy providing fatty acids. |
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What else do corticoids promote?
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They also promote the breakdown of proteins, in tissues other than the liver. The resulting increase in blood amino acids provide a source for synthesizing glucose and other molecules in the liver.
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What other effects do glucocorticoids possess?
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They are also anti-inflammatory. they inhibit as well histamine secretion, inhibit lymphocyte production and stabilize macrophage lysosomes.
They increase gastric acid secretion production by augmenting parietal cell activity. |
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What is aldosterone?
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It is a mineralcorticoid. It originates from the adrenal cortex.(glomerulosa)
Secretion is stimulated by ACTH and by the renin/angiotensin axis. |
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What is renin?
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It stimulates conversion of the protein angiotensinogen to angiotensin 1, which then becomes angiotensin 11, via the angiotensin converting enzyme.
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What does angiotensin 11 do?
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It stimulates the synthesis and release of aldosterone by the adrenal cortex.
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Elevated blood potassium stimulates adrenal aldosterone secretion whereas elevated sodium decreases secretion. TRUE/FALSE
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TRUE.
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Mineralcorticoids are what type of structure?
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Steroid. It stimulates kidney reabsorption of sodium into the circulation with exchange for potassium.
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What is Conn's syndrome?
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Excess aldosterone may be primary, the effect of primary adrenal hyperplasia(primary hyperaldosteronism); or secondary to excess renin(2ary hyperaldosteronism) which may occur with renin producing juxtaglomerular cell tumors or other kind of renal disorders.
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Aldosteron, in addition to promoting potassium exchange for sodium, also promotes exchange of H+ for sodium. TRUE/FALSE
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TRUE.
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Where is Insulin produced?
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In the beta cells of the pancreas.
Its secretion is stimulated by increased blood glucose concentration. An excess of certain amino acids also stimulates insulin secretion, which clears the blood of excess amino acids by promoting the entry of certain amino acids into cells. |
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What are the functions of insulin?
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It facilitates the uptake of blood glucose by cells for storage as glycogen(liver and muscle).
Stimulates synthesis of protein, it increases amino acid uptake by cells as well as synthesize fatty acids in the liver which are transported via VLDL lipoproteins to adipose cells, where they are stored as triglycerides. |
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Insulin inhibits gluconeogenesis, and does not influence glucose uptake in the brain. TRUE/FALSE
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TRUE. Glucose can enter the brain without glucose.
The brain cannot use fatty acids as fuel, because they do not cross the blood brain barrier. |
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The presence or absence of insulin helps to decide whether carbohydrates or lipids will be the main source of energy. TRUE/FALSE
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TRUE. Excess glucose isdriven into cells where it is stored as glycogen(glycogenesis) or broken down(glycolysis) and is used in the Kreb's cycle to generate ATP as an energy source.
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A lack of insulin or its receptors occurs in diabetes mellitus>. TRUE/FALSE
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TRUE. Fatty acids are stored as triglycerides in adipose tissue. With a lack of insulin, excess fatty acids which do not enter the Kreb's cycle are diverted to form ketones, such as acetoacetic acid, causing an acidosis, whereas some form excess cholesterol, phospholipids and triglycerides in the liver, which incorporates these lipids into VLDL lipoproteins for bloodstream export.
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What is glucagon?
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Its origen are the alpha cells of the pancreas. It is a polypeptide.
Its secretion is inhibited by increased blood glucose concentration. An excess of certain amino acids stimulates glucagon secretion. |
