Physiology week 2
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Questions and Answers

What is the primary mechanism of calcium absorption in the small intestine?

  • Passive diffusion
  • Facilitated diffusion
  • Exocytosis
  • Active transport via calcium-binding protein (correct)

    • What is the primary function of 1,25-dihydroxyvitamin D in calcium homeostasis?

  • Inhibition of PTH secretion
  • Regulation of intestinal calcium absorption (correct)
  • Stimulation of osteoclast activity
  • Inhibition of osteoblast activity

    • What is the primary effect of PTH on osteoclasts?

  • Stimulation of osteoblast activity
  • Inhibition of osteoclast activity
  • Stimulation of osteoclast activity (correct)
  • Inhibition of osteoblast activity

    • Which hormone plays a major role in regulating bone formation and resorption?

    <p>PTH</p> Signup and view all the answers

    What is the primary function of calcitonin in calcium homeostasis?

    <p>Inhibition of osteoclast activity</p> Signup and view all the answers

    Which of the following is a consequence of hypocalcemia?

    <p>All of the above</p> Signup and view all the answers

    What is the primary stimulus for calcitonin secretion from parafollicular cells in the thyroid gland?

    <p>Increased plasma Ca2+ concentration</p> Signup and view all the answers

    What is the effect of parathyroid hormone on phosphate reabsorption in the kidney?

    <p>It inhibits phosphate reabsorption</p> Signup and view all the answers

    What is the role of vitamin D in intestinal calcium absorption?

    <p>Vitamin D stimulates calcium absorption in the small intestine</p> Signup and view all the answers

    What is the effect of calcitonin on osteoclastic bone resorption?

    <p>It inhibits osteoclastic bone resorption</p> Signup and view all the answers

    What is the effect of PTH on bone metabolism?

    <p>It promotes bone resorption</p> Signup and view all the answers

    What is the relationship between calcitonin and PTH in terms of their effects on bone metabolism?

    <p>They have antagonistic effects on bone metabolism</p> Signup and view all the answers

    What is the primary function of 1,25-dihydroxycholecalciferol in the small intestine?

    <p>To increase the expression of calcium-binding proteins</p> Signup and view all the answers

    What is the effect of increased circulating levels of PTH on 1α-hydroxylase activity?

    <p>It increases 1α-hydroxylase activity</p> Signup and view all the answers

    What is the primary role of vitamin D in bone metabolism?

    <p>To stimulate osteoclast activity and promote bone resorption</p> Signup and view all the answers

    What is the consequence of vitamin D deficiency in children?

    <p>Rickets</p> Signup and view all the answers

    What is the effect of 1,25-dihydroxycholecalciferol on phosphate reabsorption in the kidney?

    <p>It stimulates phosphate reabsorption</p> Signup and view all the answers

    What is the stimulus for the production of the active metabolite of vitamin D in the kidney?

    <p>Low dietary intake of calcium</p> Signup and view all the answers

    In which cell type does PTH bind to stimulate bone resorption?

    <p>Osteoblasts</p> Signup and view all the answers

    What is the effect of PTH on osteoblast activity?

    <p>PTH increases osteoblast activity</p> Signup and view all the answers

    What is the primary role of vitamin D in bone metabolism?

    <p>Vitamin D increases calcium absorption in the intestine</p> Signup and view all the answers

    What is the consequence of PTH-mediated bone resorption?

    <p>Release of calcium ions from the bone matrix</p> Signup and view all the answers

    What is the indirect mechanism by which PTH stimulates bone resorption?

    <p>PTH induces the release of IL-6 and RANK ligand from osteoblasts</p> Signup and view all the answers

    In which tissue does PTH stimulate the activation of vitamin D?

    <p>Kidney</p> Signup and view all the answers

    What is the effect of decreased plasma Ca2+ concentration on 1α-hydroxylase activity?

    <p>It increases the activity of 1α-hydroxylase enzyme.</p> Signup and view all the answers

    What is the role of vitamin D in bone mineralization?

    <p>It increases plasma levels of both Ca2+ and phosphate to promote mineralization of new bone.</p> Signup and view all the answers

    What is the consequence of vitamin D deficiency in adults?

    <p>Osteomalacia, a condition in which new bone fails to mineralize, resulting in bending and softening of the weight-bearing bones.</p> Signup and view all the answers

    What is the role of osteoblasts in bone remodeling?

    <p>They deposit new bone tissue, increasing bone mass.</p> Signup and view all the answers

    What is the effect of 1,25-dihydroxycholecalciferol on calcium absorption in the small intestine?

    <p>It stimulates the formation of calcium-binding proteins, promoting calcium absorption.</p> Signup and view all the answers

    What is the role of 1,25-dihydroxycholecalciferol in bone mineralization?

    <p>It promotes bone mineralization by stimulating osteoblast activity.</p> Signup and view all the answers

    What is the effect of PTH on phosphate reabsorption in the proximal convoluted tubule of the nephron?

    <p>Inhibition of phosphate reabsorption</p> Signup and view all the answers

    What is the role of 1,25-dihydroxycholecalciferol in the small intestine?

    <p>It stimulates calcium absorption in the small intestine</p> Signup and view all the answers

    What is the effect of PTH on bone metabolism?

    <p>It stimulates osteoclast activity and bone resorption</p> Signup and view all the answers

    What is the consequence of vitamin D deficiency in children?

    <p>Rickets</p> Signup and view all the answers

    What is the role of PTH in regulating vitamin D synthesis?

    <p>It stimulates vitamin D synthesis</p> Signup and view all the answers

    What is the effect of vitamin D deficiency on bone metabolism?

    <p>It leads to a decrease in osteoblast activity and bone formation</p> Signup and view all the answers

    What is the effect of increased circulating levels of PTH on 1α-hydroxylase enzyme activity?

    <p>Stimulation of the enzyme</p> Signup and view all the answers

    Which of the following is the primary site of vitamin D synthesis?

    <p>Skin and kidney</p> Signup and view all the answers

    What is the role of vitamin D in bone mineralization?

    <p>Increase in both calcium and phosphate concentrations</p> Signup and view all the answers

    What is the effect of PTH on vitamin D synthesis?

    <p>Stimulation of vitamin D synthesis</p> Signup and view all the answers

    What is the role of vitamin D in the small intestine?

    <p>Increase in both calcium and phosphate absorption</p> Signup and view all the answers

    What is the primary function of vitamin D in conjunction with PTH?

    <p>Regulation of both calcium and phosphate concentrations</p> Signup and view all the answers

    What is the primary stimulator of the 1α-hydroxylase enzyme activity?

    <p>Decreased plasma calcium concentration</p> Signup and view all the answers

    What is the primary purpose of the regulation of vitamin D synthesis?

    <p>To regulate plasma calcium levels</p> Signup and view all the answers

    What is the primary role of vitamin D in bone mineralization?

    <p>To promote mineralization of new bone</p> Signup and view all the answers

    What is the effect of vitamin D on osteoclast activity?

    <p>It increases osteoclast activity</p> Signup and view all the answers

    What is the consequence of vitamin D deficiency in children?

    <p>Rickets</p> Signup and view all the answers

    What is the effect of 1,25-dihydroxycholecalciferol on calcium absorption in the small intestine?

    <p>It increases calcium absorption</p> Signup and view all the answers

    What stimulates the activity of the 1α-hydroxylase enzyme in the kidney?

    <p>Increase in parathyroid hormone levels</p> Signup and view all the answers

    What is the primary stimulus for the synthesis of 1,25-dihydroxycholecalciferol in the kidney?

    <p>Decreased calcium levels</p> Signup and view all the answers

    What is the role of 1,25-dihydroxycholecalciferol in bone mineralization?

    <p>Regulating calcium and phosphate metabolism</p> Signup and view all the answers

    What is the primary site of vitamin D synthesis?

    <p>Skin</p> Signup and view all the answers

    What is the function of the 25-hydroxycholecalciferol-binding protein in plasma?

    <p>Transporting vitamin D metabolites</p> Signup and view all the answers

    What is the effect of decreased calcium levels on vitamin D synthesis?

    <p>Stimulating parathyroid hormone production</p> Signup and view all the answers

    What is the primary consequence of failing to comply with a medically prescribed steroid taper?

    <p>Addisonian crisis</p> Signup and view all the answers

    What is the primary source of excess cortisol in Cushing's syndrome?

    <p>Adrenal gland tumor</p> Signup and view all the answers

    What are the common symptoms of both Cushing's disease and Cushing's syndrome?

    <p>All of the above</p> Signup and view all the answers

    What is the primary cause of Cushing's disease?

    <p>Pituitary adenoma</p> Signup and view all the answers

    What is the primary difference between Cushing's disease and Cushing's syndrome?

    <p>The source of excess cortisol</p> Signup and view all the answers

    What is the primary mechanism of Adrenal Insufficiency in Addison's Disease?

    <p>Autoimmune destruction of adrenal cortex</p> Signup and view all the answers

    What is the characteristic feature of Primary Hypercortisolism (Cushing's Syndrome)?

    <p>Low ACTH levels and adrenal gland tumor</p> Signup and view all the answers

    What is the most common cause of Secondary Hypercortisolism (Cushing's Disease)?

    <p>Pituitary tumor</p> Signup and view all the answers

    What is the hallmark of Iatrogenic Cushing's Syndrome?

    <p>High Cortisol levels and low ACTH levels</p> Signup and view all the answers

    What is the threshold of adrenal cortex destruction required for Adrenal Insufficiency to occur?

    <p>At least 90% of the adrenal cortex</p> Signup and view all the answers

    What is the characteristic feature of Secondary Adrenal Insufficiency (Hypopituitarism)?

    <p>Low ACTH and low cortisol levels</p> Signup and view all the answers

    What is the primary symptom of adrenal insufficiency in women?

    <p>Decreased libido and pubic hair</p> Signup and view all the answers

    What is the cause of secondary adrenal insufficiency?

    <p>Lack of ACTH</p> Signup and view all the answers

    What is the effect of Addison's disease on cortisol levels?

    <p>Decreased cortisol levels</p> Signup and view all the answers

    What is the treatment for Addison's disease?

    <p>Replacement of glucocorticoids and mineralocorticoids</p> Signup and view all the answers

    What is the effect of Addison's disease on pubic and axillary hair in women?

    <p>Decreased hair growth</p> Signup and view all the answers

    What is the cause of hyperkalemia in Addison's disease?

    <p>Decreased aldosterone levels</p> Signup and view all the answers

    What is a consequence of chronic stress on the cardiovascular system?

    <p>Left ventricular hypertrophy</p> Signup and view all the answers

    What is the primary mechanism by which chronic stress impairs immune function?

    <p>Impaired immune surveillance</p> Signup and view all the answers

    Which of the following is a consequence of chronic stress on metabolism?

    <p>Decreased glucose tolerance</p> Signup and view all the answers

    What is the primary effect of glucocorticoids on metabolism during chronic stress?

    <p>Increased gluconeogenesis</p> Signup and view all the answers

    What is the primary consequence of chronic stress on the central nervous system?

    <p>Impaired judgement and impulse control</p> Signup and view all the answers

    What is the primary effect of chronic stress on behavior?

    <p>Increased irritability and hostility</p> Signup and view all the answers

    What is the term used to describe the state of balance and stability in an organism?

    <p>Homeostasis</p> Signup and view all the answers

    Who is credited with the discovery of the 'fight or flight' response?

    <p>Walter Cannon</p> Signup and view all the answers

    What is the term used to describe the deviation from a normal or steady state?

    <p>Stress</p> Signup and view all the answers

    What is the name of the scientist who demonstrated that stress can alter an organism's resistance to disease?

    <p>Louis Pasteur</p> Signup and view all the answers

    What is the term used to describe the system-wide arousal of the body in response to physical or psychological danger?

    <p>Fight or flight response</p> Signup and view all the answers

    Who is credited with the discovery that stress can cause diseases?

    <p>Galen</p> Signup and view all the answers

    What is associated with negative feelings and disturbed bodily states?

    <p>Distress</p> Signup and view all the answers

    What is the effect of chronic GC exposure on adipose tissue function and lipid metabolism?

    <p>Promotes insulin resistance</p> Signup and view all the answers

    What determines individual differences in stress sensitivity?

    <p>All of the above</p> Signup and view all the answers

    What is the effect of chronic stress on the HPA axis?

    <p>Enhanced susceptibility to activation</p> Signup and view all the answers

    What is associated with positive feelings and healthy bodily states?

    <p>Eustress</p> Signup and view all the answers

    What is the effect of cortisol on insulin resistance?

    <p>Promotes insulin resistance</p> Signup and view all the answers

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