Endocrinology

Question 1

21248 – Insulin
1: augments the activity of hormone-sensitive lipase in fat cells
2: secretion is controlled by a pituitary hormone
3: inhibits lipoprotein lipase in fat cells
4: secretion is increased by vagal stimulation

Answer 1

FFFT
Ganong 13th Ed. Ch. 19 P. 288 Guyton 7th Ed. Chapter: 78 Page: 926-928
1: inhibit activity of hormone-sensitive lipase in fat cells
3: stimulates lipoprotein lipase in vicinity of fat cells

Question 2

13273 – The primary physiological action of insulin is to increase
A. glycogen synthesis by the liver
B. lipid synthesis by the liver and fat depots
C. glucose uptake by the brain
D. glucose uptake by the muscles
E. protein synthesis

Answer 2

D
The principal action of insulin in muscle, adipose tissue and connective tissue is the facilitation of entry of glucose into the cells by an action on the cell membrane (D true). Insulin has additional effects on the liver facilitating glycogen synthesis and decreased glucose output. Insulin also increases lipid synthesis in the liver and adipose tissue inhibiting hormone sensitive lipase, facilitating amino acid storage and protein synthesis in ribosomes. Glucose uptake by the brain is not insulin dependent.

Question 3

15483 – Insulin facilitates the glucose uptake in
1: ‘A’ cells of the pancreatic islets
2: intestinal mucosa
3: adipocytes
4: kidney tubules

Answer 3

TFTF
Refer to Ganong, 19th Ed, Ch 19, page 319 and following

Question 4

21253 – Insulin differs from growth hormone in that it
1: inhibits hormone-sensitive lipase in fat cells
2: increases amino-acid transport across muscle cell membranes
3: stimulates lipoprotein lipase in vicinity of fat cells
4: decreases somatomedin synthesis

Answer 4

TFTF
Ganong 13th Ed. CHAPTER: 19, 17 PAGE 285, 253

Question 5

23214 – Which of the following increase the secretion of insulin
1: raised plasma glucose concentration
2: glucagon
3: gastrin
4: vagal stimulation of beta cells

Answer 5

TTTT
Ganong 16th ed. CHAPTER: 19 PAGE: 314 (Table 19-8)
2: glucagon increases blood glucose –> increase secretion of insulin

Question 6

23579 – Changes resulting from insulin deficiency include
1: diminished growth
2: reduced lipogenesis
3: decreased glucose transport into muscle
4: decreased intestinal absorption of glucose

Answer 6

TTTF
Guyton 7th ed. CHAPTER:78 PAGE: 923-929

Question 7

23939 – Which of the following comments regarding Glucagon are true
1: it increases ketone body formation
2: it is calorigenic via increased hepatic clearance of amino acids
3: in large doses, it is a positive ionotrope
4: it causes glycogenolysis in muscles

Answer 7

TTTF
Ganong 20th Edition, page 337
4 - glycogenolysis in liver only

Question 8

23224 – Glucagon
1: increases glycogenolysis in muscle
2: increases gluconeogenesis
3: decreases lipolysis
4: increases ketone body formation in liver

Answer 8

FTFT
Ganong PAGE: 271, 283

Question 9

23229 – Glucagon secretion is stimulated by
1: amino acids
2: raised glucose level in plasma
3: gastrin
4: somatostatin

Answer 9

TFTF
Ganong 13th Edition CHAPTER: 19 PAGE: 291
4: somatostatin inhibits insulin

Question 10

15117 – Glucagon secretion is increased by
1: beta-adrenergic stimulants
2: amino-acids
3: gastrin
4: somatostatin

Answer 10

TTTF
Refer to Ganong, 19th Ed, Ch 19, page 332 and following

Question 11

22579 – Glucagon secretion is increased by
1: hypoglycaemia
2: raised plasma level of some amino acids
3: cholecystokinin-pancreozymin
4: somatostatin

Answer 11

TTTF
Ganong 15th ed. CHAPTER: 19 PAGE: 327

Question 12

13421, 20595 – S: Glucagon elevates blood glucose level because R: glucagon enhances glycogenolysis in muscle

Answer 12

S is true and R is false
Ganong 11th Edition CHAPTER: 19 PAGE: 290.
Glucagon elevates blood glucose (S true) by
stimulating phosphorylation of glycogen in the liver via adenylate cyclase. It also increases
gluconeogenesis from amino acids in the liver. Glucagon does not cause glycogenolysis in muscle (R false).

Question 13

20127 – S. Ketosis not uncommonly occurs in starvation BECAUSE R. carbohydrate is anti-ketogenic

Answer 13

S is true, R is true and a valid explanation of S
Ganong 13th Ed. Chapter: 17 Page: 246-247

Question 14

9850 – A patient suffers from a metabolic acidosis due to excessive production of keto-acids. In this state all of the following are true EXCEPT
A. urinary NH4 excretion is increased
B. there is decreased PCO2 of the arterial blood
C. the renal excretion of titratable acid is increased
D. there is a decrease in the intracellular H+ concentration
E. there is an increase in the rate of production of bicarbonate

Answer 14

D
Guyton, 7th ed, Ch 37

Question 15

12808 – In adipose tissue intracellular lipase
1: is liberated into the circulation by glycogen
2: activity is increased during starvation
3: is activated by the sympathetic nervous system
4: activity is increased following insulin administration

Answer 15

FTTF
Intracellular lipase is the hormone-sensitive lipase which is confined to adipose tissue and catalyses the breakdown of stored triglyceride to glycerol and fatty acids, the latter being released into the circulation. The enzyme is different from lipoprotein lipase, which is located in the endothelium of the capillaries, catalyses the breakdown of circulating triglyceride, is not hormone-sensitive and requires heparin as a co-factor. The hormone-sensitive lipase does not enter the circulation (A false) but is activated by catecholamines released by sympathetic nerve stimulation, growth hormones, cortisol, thyroxine, and, therefore, stress and starvation (B and C true). This lipase is, however, inhibited by feeding and insulin (D false).

Question 16

22714 – In starvation there is
1: increased hepatic gluconeogenesis
2: adaptive utilization of ketone bodies by the brain
3: increased activity of hormone-sensitive lipase
4: increased glucose synthesis from fatty acids

Answer 16

TTTF
Ganong 19th Edition CHAPTER: 17 PAGE: 285

Question 17

25770 – Metabolic responses to fasting include all of the following EXCEPT
A. hepatic gluconeogenesis
B. hepatic glycogenolysis
C. muscle and visceral protein catabolism
D. falling glucagon levels
E. ketogenesis

Answer 17

D

Question 18

5728 – Concerning the metabolic effects of starvation in the postoperative period
A. glycogen storage in the liver provides a source of glucose for several days
B. fatty acids provide the main metabolic fuel
C. thyroxine conversion plays little role
D. visceral protein is preserved
E. glycogen levels fall and insulin levels rise

Answer 18

B
During starvation energy is derived initially from glycogen stores but these are rapidly depleted. In seven days fat is the major energy source, resulting in an increase in the production of plasma ketones

Question 19

12843 – When food has not been taken for several days, there is usually
1: an increase in plasma ketone
2: an increase in urinary urea output
3: a decrease in respiratory quotient
4: an increase in acidity of the urine

Answer 19

TFTT
During starvation energy is derived initially from glycogen stores but these are rapidly depleted. In seven days fat is the major energy source, resulting in an increase in the production of plasma ketones (A true) and a fall in the respiratory quotient towards 0.7 (C true). Despite increased protein catabolism with amino acid breakdown urea production and excretion in the urine is decreased (B false). There is an associated increase in the excretion of titratable acid, especially phosphate and sulphate, making the urine more acid (D true).

Question 20

21913 – During glucose metabolism
1: the steps from G-6-P to pyruvate by the Embden-Meyerhof pathway occur in the cytoplasm
2: conversion of glucose to G-6-P is irreversible in non-gluconeogenic tissue e.g. muscle
3: pyruvate is oxidised in mitochondria
4: fructose catabolism via the Embden-Meyerhof pathway is dependent on the presence of glucagons

Answer 20

TTTF
Ganong 19th Ed. Chapter: 17 Page: 274-280

Question 21

13279 – Which of the following increases blood glucose, mobilises fat from depots and has no effect on protein synthesis?
A. insulin
B. glucagon
C. adrenaline
D. cortisol
E. growth hormone

Answer 21

C
Adrenaline increases blood glucose by increasing hepatic glycogenolysis and increases circulating free fatty acids (C true). Glucagon has similar effects but also increases gluconeogenesis from available amino acids (B false). Cortisol increases protein catabolism and tends to increase blood glucose levels (D false). Growth hormone stimulates protein synthesis, increases hepatic glucose production and elevates free fatty levels in plasma (E false). Insulin, on the other hand, lowers blood glucose levels, increases protein synthesis and increases triglyceride deposition in adipose tissue (A false).

Question 22

20853 – S. A high intake of glucose is dealt with in the body by its storage predominantly as glycogen BECAUSE R. with a high intake of glucose, insulin is secreted and glycogen formation is increased

Answer 22

S is false and R is true
Ganong 20th Edition, Ch 17, pages 278-284. Pending review. Nov 2002

Question 23

21243 – In the thyroid
1: iodide enters cells against a concentration gradient
2: thiocyanate (or perchlorate) competitively inhibits iodide uptake
3: LATS (long acting thyroid stimulator) resembles TSH in its actions
4: daily synthesis of triiodothyronine is greater than that of tetraiodothyronine (thyroxine)

Answer 23

TTTF
Guyton 7th ed. CHAPTER: 76 PAGE: 898-905
Iodine is actively concentrated in thyroid cells up to approximately 40 times the level in serum. Thiocyanate (or perchlorate) competitively inhibits iodide uptake. The thyroid normally secretes about 80 μg of thyroxine and about 4 μg of triiodothyronine per day.

Question 24

10451, 13554, 21743 – In the thyroid
1: iodide enters cells against a concentration gradient
2: daily synthesis of triiodothyronine is greater than that of thyroxine
3: thyroid-stimulating immunoglobulin (TSI) resembles thyroid stimulating hormone (TSH) in its actions
4: thiocyanate (or perchlorate) competitively inhibits iodide uptake

Answer 24

TFTT
MCQ BOOK QUESTION 4TH EDITION (2.065). Iodine is actively concentrated in thyroid cells up to approximately 40 times the level in serum (A true). Thiocyanate (or perchlorate) competitively inhibits iodide uptake (D true). The thyroid normally secretes about 80 μg of thyroxine and about 4 μg of triiodothyronine per day (B false). Thyroid stimulating immunoglobulin is similar in its actions to pituitary TSH (C true).

Question 25

22359 – Thyroid hormones 1: increase gluconeogenesis in liver 2: increase glycogen content in muscle 3: lower plasma cholesterol 4: increase the duration of tendon reflexes

Answer 25

TFTF Ganong 13th Edition CHAPTER: 1 PAGE: 269-270 Thyroid hormones are catabolic 1: true 2: increase muscle protein breakdown 3: formation of LDL receptors

Question 27

23879 – Thyroid hormone excess causes 1: creatinuria 2: increased glucose absorption from small intestine 3: increased uric acid excretion in urine 4: decreased pulse pressure

Answer 27

TTTF Ganong 16th ed. CHAPTER: 18 PAGE: 293-294 1,3: increased muscle protein breakdown 2: increased rate of glucose/carb absorption 4: high BP

Question 28

10456, 13559, 23444 – Diiodotyrosine is 1: physiologically active 2: not stored in the thyroid as part of the thyroglobulin molecule 3: not found in the blood 4: loosely bound to plasma proteins

Answer 28

FFTF MCQ BOOK QUESTION 4TH EDITION (2.066) Monoiodotyrosine and diiodotyrosine are formed in the thyroid cell by enzymatic binding of iodine to the tyrosine molecules attached to the thyroglobulin molecule. Diiodotyrosine forms about one-third of the iodinated compounds in the thyroglobulin complex (B false). Two diiodotyrosine molecules undergo oxidative condensation to form thyroxine, still linked to thyroglobulin. After proteolysis of thyroglobulin the diiodotyrosine and monoiodotyrosine liberated into the cytoplasm are deiodinated and the iodine liberated is reutilised. Thus diiodotyrosine is not secreted to the blood (C true, D false) and has essentially no biological action as thyroid hormone (A false).

Question 29

23589 – Tetraiodothyronine (thyroxine) and triiodothyronine 1: circulate in plasma predominantly bound to proteins 2: levels increase in plasma during pregnancy and mild hyperthyroidism normally occurs 3: increase glucose absorption from small intestine 4: have no effect on erythropoiesis

Answer 29

TFTF Guyton 7th ed. CHAPTER: 76 PAGE: 897-903 2: level of thyroid binding globulin raise during pregnancy --> # of free T3/T4 remains the same

Question 30

10446 – The release of thyroid-stimulating hormone (TSH) by the anterior pituitary is increased by 1: nerve impulses in nerve tracts from the hypothalamus 2: reduced blood levels of thyroxine 3: a hypothalamic releasing factor 4: a hot environment raising the temperature of blood passing through the hypothalamus

Answer 30

FTTF Anterior pituitary thyrotrophin cells are under the stimulatory control of thyrotropin releasing hormone from the hypothalamus via the hypothalamo-hypophyseal portal system, and are inhibited by circulating thyroxine and triiodothyronine (B and C true). Unlike the posterior pituitary there are no neural connections to the anterior pituitary (A false). The response to cold stress involves thyroid activation to assist in calorigenesis by raising metabolic rate, but this would be counter-adaptive in heat stress and, of course, does not occur (D false).

Question 31

9880 – S: There is very little free thyroxine in the plasma because R: thyroxine is bound to thyroxine-binding prealbumin in the plasma

Answer 31

S is true, R is true but not a valid explanation of S Ganong, 19th ed, Ch 2 Majority of thyroxine binds to TBG/albumin

Question 32

15132 – Thyroid stimulating hormone (TSH) 1: requires glycosylation for full biological activity 2: is primarily degraded in the liver 3: acts by combining with a G protein linked receptor 4: causes exocytosis of colloid in the thyroid

Answer 32

TFTF Refer to Ganong, 19th Ed, Ch 18, page 312

Question 33

20721 – S. Patients with high levels of TBG (thyroxinebinding globulin) are usually euthyroid BECAUSE R. high TBG levels suppress pituitary thyrotrophin (THS)

Answer 33

S is true and R is false Ganong 20th Edition, page 312.

Question 34

23944 – Parathyroid hormone 1: is secreted by the oxyphil cells of the parathyroid gland 2: in excess causes hypophosphaemia 3: deficiency is a cause of calcium-containing renal calculi 4: increases distal tubular reabsorption of calcium

Answer 34

FTFT Ganong 13th ed. CHAPTERS: 21 PAGES: 328-329 1: secreted by chief cells 3: hypercalcaemia

Question 35

23454 – Parathyroid hormone (PTH) secretion is 1: increased by a low plasma Ca2+ level 2: decreased by a low plasma PO4- level 3: increased in chronic renal disease 4: reduced by ?-adrenergic stimulation

Answer 35

TFTF Guyton 16th ed. Chapter: 21 Pages: 356-357 PTH secretion regulated by Ca level, independent of pituitary gland/CNS

Question 36

21443 – PTH (parathyroid hormone) 1: increases mobilisation of Ca2+ from bone 2: increases reabsorption of Ca2+ from distal tubules of kidney 3: increases synthesis of 1, 25-dihydroxycholecalciferol, the 'active' metabolite of vitamin D 4: increases phosphate reabsorption from renal tubules

Answer 36

TTTF Ganong 16th Ed. CHAPTER: 21 PAGE: 356

Question 37

25758 – Hypercalcaemia A. results in hypovolaemia from the kidney’s inability to retain water B. can be rescued by administration of intravenous biphosphonate C. is a common sequel of total thyroidectomy D. can be managed by oral vitamin D administration E. is invariably associated with elevated serum parathyroid hormone levels

Answer 37

B

Question 38

13564 – Calcitonin 1: deficiency has profound clinical effects 2: is secreted mainly by parafollicular cells within the thyroid 3: is only secreted when calcium levels in the blood exceed 2.4 mmol/1 (9.5 mg/dl) 4: lowers serum calcium levels by inhibiting bone resorption

Answer 38

FTTT Calcitonin is secreted by the parafollicular of C cells in the thyroid gland (B true) but only when the plasma calcium level exceeds 2.4 mmol/1 (9.5 mg/dl) (C true). Calcitonin lowers plasma calcium and phosphate levels by inhibiting bone resorption (D true). Parathyroid hormone promotes the synthesis of 1,25 dihydroxycholecalciferol in the kidney but calcitonin has no effect on this factor. (A false).

Question 39

9983 – Calcitonin 1: lowers serum calcium levels by inhibiting bone resorption 2: is only secreted when calcium levels in the blood exceed 2.4 mmol/l (9.5 mg/dl) 3: is secreted mainly by parafollicular cells within the thyroid 4: secretion is increased by gastrin

Answer 39

TTTT Ganong, 19th ed, Ch 21

Question 40

23449 – Calcitonin 1: promotes synthesis of 1,25 dihydroxycholecalciferol in the kidney 2: is secreted mainly by parafollicular cells within the thyroid 3: is only secreted when calcium levels in the blood exceed 2.4 mmol/l 4: lowers serum calcium levels by inhibiting bone resorption

Answer 40

FTTT MCQ book question 4th edition (2.067).

Question 41

23929 – Calcitonin 1: increases Ca2+ concentration of plasma 2: increases absorption of Ca2+ from bone 3: increases absorption of Ca2+ from small intestine 4: secretion is increased by a raised Ca2+ concentration of plasma

Answer 41

FFFT Ganong 13th Ed. CHAPTER: 21 PAGE: 330 1-3 = action of PTH

Question 42

15493 – The absorption of calcium from the upper small intestine is facilitated by 1: 1, 25 - dihydroxycholecalciferol 2: a calcium-binding protein in small intestinal epithelium 3: a low ionised calcium in plasma 4: phosphate in small intestine

Answer 42

TTTF Refer to Guyton, 7th Ed, Ch 79, page 937-939; Ganong, 19th Ed, Ch 25, page 456

Question 43

21673 – Adrenaline 1: stimulates glycogenolysis in liver and muscle 2: mobilises free fatty acids from adipocytes 3: increases the B.M.R. (Basal Metabolic Rate) 4: increases the pulse pressure

Answer 43

TTTT Ganong - 13th ed. Chapters: 17, 20, 31 Pages: 231,238,299-300, 495

Question 44

23574 – Noradrenaline causes 1: increased cardiac contractility 2: vasodilation in skeletal muscle and liver 3: increased myocardial excitability 4: widening of the pulse pressure

Answer 44

TFTF Ganong 13th Edition CHAPTERS: 19 PAGES: 300 Norad causes vasoconstriction (A1) 2: ADRENALINE causes vasodilation in skeletal muscle and liver (B2) 4: normal pulse pressure due to vasoconstriction effect

Question 45

21353 – Which of the following is/are induced by noradrenaline? 1: reduction of the cardiac output 2: constriction of skeletal muscle arterioles 3: stimulation of hydrolysis of fat to release fatty acids and glycerol 4: stimulation of the secretion of gastric parietal cell HCl.

Answer 45

TTTF 1: increased contractility but decreased CO due to vasoconstriction effect 2: Norad causes vasoconstriction (A1)

Question 46

14902 – S: When noradrenaline is infused into normal humans the pulse slows because R: noradrenaline has no beta-adrenergic agonist activity

Answer 46

S is true and R is false Refer to Ganong, 19th Ed, Ch 20, page 342-344; Ch 31, page 573 Norad binds to B1 receptors on cardiac muscle cells --> increases force of contraction & relaxation of muscles in order to give effective pumping (inotropic effect). Also reflex bradycardia happens due to systemic vasoconstriction

Question 47

23674 – Activation of the adrenergic nervous system may lead to the following physiological responses 1: increase in circulating renin levels 2: arteriolar coronary dilatation 3: hepatic glycogenolysis 4: pancreatic acinar secretion

Answer 47

TTTF Ganong 13th Ed. CHAPTER: 13 PAGE: 186-187 2: B - vasodilatory; A - vasoconstrictory

Question 48

18844 – Which of the following is inhibited by both alpha and beta adrenergic agonist substances? A. intestinal smooth muscle B. terminal bronchiolar smooth muscle C. pulmonary arteriolar smooth muscle D. cardiac muscle E. cutaneous vascular smooth muscle

Answer 48

A

Question 49

24069 – Alpha-adrenergic receptors are found in 1: intestinal smooth muscle 2: terminal bronchial smooth muscle 3: cutaneous vascular smooth muscle 4: cardiac muscle

Answer 49

TFTF Alpha receptors found in : intestinal smooth muscles (contraction of sphincters), cutaneous vascular smooth muscle, sweat glands and pupils (dilation)

Question 50

15067 – The effects of Dopamine include 1: activation of dopaminergic receptors to decrease appetite 2: a net negative inotropic effect 3: stimulation of prolactin secretion 4: a net decrease in peripheral vascular resistance

Answer 50

TFFF Refer to Ganong, 19th Ed, Ch 15, page 252 2: positive inotropic - B1 activity 3: inhibits prolactin secretion 4: causes general vasoconstriction (despite mesentery and renal vasodilation) --> increases peripheral vascular resistance

Question 51

9988 – Factors increasing both glucocorticoid and aldosterone secretion include 1: haemorrhage 2: a high potassium (K+) diet 3: anxiety 4: assuming the erect posture content of the mucosal cells is decreased

Answer 51

TFTF Ganong, 19th ed, Ch 20. This question has been reviewed and has not been changed. 9 Dec 2002. Comments: The word "assume" in option four should be interpreted as follows: "assume the erect posture" = "to take up the erect posture.

Question 52

19899 – All but one of the following are associated with adrenal cortical hyperfunction. Which is the EXCEPTION? A. osteoporosis B. excessive fat deposition C. peptic ulceration D. aseptic necrosis of bone E. delayed closure of epiphyses

Answer 52

E Ganong 16th Edition Chapter: 20 Page: 336-337; 346 C: increases HCL & pepsin secretion

Question 53

14671 – Glucocorticoids 1: produce multiple effects via transcription of DNA 2: modulate sensitivity to olfactory stimuli 3: are essential for vascular smooth muscle responses to catecholamines 4: stimulate the production of interleukin-2

Answer 53

TTTF Refer to Ganong, 19th Ed, Ch 20, page 350 and following

Question 54

23959 – Cortisol 1: promotes gluconeogenesis in the liver 2: decreases utilization of glucose by muscle cells 3: increases utilization of free fatty acids by adipocytes 4: increases the intensity of antigen-antibody reactions

Answer 54

TTTF Guyton 7th Ed. Ch. 77 P. 915 Ganong 13th Ed. Chapter: 20 Page: 310-311 4: immunosuppressive

Question 55

24359 – Cortisol 1: increases gluconeogenesis by the liver 2: decreases glucose utilisation by muscle cells 3: increases free fatty acid mobilization 4: increases ACTH secretion via a feedback control mechanism

Answer 55

TTTF Ganong, 19th Ed CHAPTER:20 PAGE: 353-358

Question 56

21843 – The metabolic actions of cortisol include 1: stimulated synthesis of hepatic gluconeogenic enzymes 2: mobilization of extra-hepatic amino acids 3: decreased glucose utilization by cells 4: decreased hepatic protein synthesis

Answer 56

TTTF Guyton 8th ed. Page: 846

Question 57

15127 – With regard to the pituitary 1: follicle stimulating hormone maintains spermatogenesis 2: luteinizing hormone is responsible for progesterone secretion from the corpus luteum 3: prolactin causes milk secretion from the oestrogen and progesterone primed breast 4: growth hormone produces a fall in blood urea nitrogen

Answer 57

TTTT Refer to Ganong, 19th Ed, Ch 22, page 378 and following.

Question 58

20811 – S. In patients with adrenal insufficiency excessive pigmentation of the skin indicates pituitary disease BECAUSE R. in primary adrenal insufficiency circulating ACTH levels are high

Answer 58

S is false and R is true Guyton 7th ed. CHAPTER: 77 PAGE: 920 Pigmentation is caused by high ACTH, indicating PRIMARY adrenal insufficiency (S false)

Question 59

10159 – Growth hormone 1: in excessive amounts produces ketosis 2: enhances amino acid transport through cell membranes 3: stimulates the islets of Langerhans to secrete insulin 4: acts directly on bone and cartilage to promote growth

Answer 59

TTFF Ganong, 19th ed, Ch 22 3: Does not stimulate B cells directly to secrete insulin - increases the ability of pancreas to respond to insulinogenic stimuli

Question 60

23219 – Growth hormone secretion is increased by 1: hypoglycaemia 2: exercise 3: fasting 4: L-dopa

Answer 60

TTTT Ganong 19th ed. CHAPTER: 22 PAGE: 387 (Table 22.3) 'stress'

Question 61

22594 – Prolactin secretion is increased by 1: exercise 2: surgery 3: suckling 4: dopamine

Answer 61

TTTF Ganong 15th ed. Chapter: 23 Page: 398-399 'stress'

Question 62

27556 – Concerning the effect of the anterior pituitary 1: follicle-stimulating hormone (FSH) and luteinising hormone (LH) are secreted only in females 2: luteinising hormone acts via receptors on theca interna cells 3: pulsatile release of gonadotropin-releasing hormone (GnRH) from the hypothalamus is vital 4: prolactin causes milk secretion from the oestrogen-primed and progesterone-primed breast

Answer 62

FTTT Both FSH & LH are secreted in the male as well as the female (1 False). In the male, FSH stimulates the Sertoli cells to control the maturation of spermatids to spermatozoa; and LH is trophic on the interstitial Leydig cells - stimulating androgen production. Luteinising hormone in the female acts via receptors on theca interna cells (2 True); to stimulate ovulation and luteinisation of the ovarian follicle. Research with gonadotrophic releasing hormones (GnRH) have clearly shown that a constant infusion of GnRH will down-regulate the GnRH receptor of the anterior pituitary and hence LH secretion ceases. An hourly pulse, on the other hand, will stimulate LH secretion (see Ganong) (3 True). Prolactin is another of the hormones secreted by the anterior pituitary. Its action is to stimulate milk secretion from a breast that is 'primed' by oestrogen and progesterone (4 True). Prolactin also inhibits the action of the gonadotropins.

Question 63

22088 – The increase in antidiuretic hormone secretion which follows operation is due to 1: pain 2: administration of morphine 3: loss of extracellular fluid 4: hypoxia

Answer 63

TTTF Ganong 14th ed. Page: 202

Question 64

21348 – ADH (antidiuretic hormone) 1: is synthesized in neurones different from those which synthesize oxytocin 2: can constrict the vasa recta vessels in the renal medulla 3: facilitates urine concentration in the collecting ducts 4: release is decreased when the central venous pressure falls below normal

Answer 64

TTTF Guyton 7th Ed. Ch. 75 P. 893 Ganong 13th Ed. Chapter: 14-38 Page: 196-200, 594 4: pressure falls stimilates release of ADH

Question 65

22589 – Stimuli that increase vasopressin secretion include 1: increased extracellular fluid volume 2: nicotine 3: alcohol 4: chlorpropamide

Answer 65

FTFT Ganong 16th Ed. CHAPTER: 14 PAGE: 219 drugs stimulating ADH secretion: morphine, nicotine, cholorpropamide, chlofibrate

Question 66

21718 – Increased ADH secretion is induced by 1: mild hyperosmolality of the ECF 2: severe hypovolaemia 3: mild hypovolaemia plus mild hyperosmolality of the ECF 4: severe hypovolaemia plus severe hypo-osmolality of the ECF

Answer 66

TTTT Guyton 7th ed. Chapter: 75 Page: 893-895 Ganong 19th Ed. Ch. 14 p230

Question 67

23954 – Vasopressin (ADH) secretion is affected by 1: osmoreceptors in the hypothalamus 2: low pressure receptors in the great veins and atria 3: nicotine 4: spironolactone

Answer 67

TTFF Guyton 7th ed. PAGE: 894

Question 68

13589 – Vasopressin or ADH 1: increases permeability to water of the proximal tubules 2: increase permeability to water of the collecting ducts of the kidney 3: decreases blood flow in the renal medulla 4: increases permeability of the collecting ducts of the inner medulla of the kidney to urea

Answer 68

FTTT Vasopressin or ADH is produced in the posterior part of the pituitary. It has its effect on the collecting ducts of the kidney, not on the proximal tubules (A false). In the collecting ducts it increases permeability to water (B true), urea (D true) and some other solutes. It also decreases the blood flow in the renal medulla (C true).

Question 69

22053 – Thirst is 1: controlled by a hypothalamic mechanism 2: caused by intracellular dehydration 3: stimulated by haemorrhage or low cardiac output 4: stimulated by angiotensin II

Answer 69

TTTT Guyton 7th ed. Chapter: 36 Page: 431

Question 70

22984 – Thirst is stimulated by 1: increased osmolality of plasma due to increased sodium concentration 2: angiotensin 3: decrease in ECF volume 4: increased oncotic pressure of plasma

Answer 70

TTTF Ganong 16th Ed. Chapter: 14 Page: 215-216.

Question 71

23889 – Which of the following conditions is/are important cause(s) of thirst? 1: extracellular dehydration 2: intracellular dehydration 3: elevated angiotensin levels after haemorrhage 4: extracellular hypertonicity

Answer 71

TTTT Guyton 7th Ed. Chapter: 36 Page: 431-432 Ganong 19th Ed. Chapter: 14 Page: 229-230

Question 72

20463 – S. Thirst can occur without a change in plasma osmolality BECAUSE R. haemorrhage stimulates thirst by a different mechanism to that evoked by osmo-receptors

Answer 72

S is true, R is true and a valid explanation of S Ganong 18th ed. Chapter: 14 Page: 225

Question 73

20379 – S. With haemorrhage, thirst can occur without any change in plasma osmolality BECAUSE R. with haemorrhage, increased amounts of angiotensin are liberated which stimulate the hypothalamic thirst area

Answer 73

S is true, R is true and a valid explanation of S Ganong 13th Ed. Ch. 14 P. 196

Question 74

14928 – S: In the syndrome of inappropriate ADH secretion (SIADH) the urine volume/day may be normal because R: with inappropriate ADH secretion the glomerular filtration rate may be increased

Answer 74

S is true, R is true and a valid explanation of S Refer to Guyton, Ch 36, page 431 ADH can cause constriction of vasa recta vessels of renal medulla

Question 75

13267 – Administration of growth hormone does NOT result in increased A. mitosis B. protein synthesis C. fat metabolism D. carbohydrate utilisation E. release of insulin from the pancreas

Answer 75

D Growth hormone is a protein-anabolic hormone which stimulates protein synthesis (B false) and cell proliferation via somatomedin (A false), and which increases fat metabolism by mobilising free fatty acids from adipose tissue (C false). Growth hormone does not stimulate pancreatic B cells directly, but increases the ability of the pancreas to respond to insulinogenic stimuli (E false). Growth hormone decreases glucose utilisation, and the glucose uptake into some tissues (D true).

Question 76

22709 – The human pineal gland 1: contains serotonin 2: is outside the blood brain barrier 3: contains melatonin 4: influences K\p+ metabolism

Answer 76

TTTF Ganong 16th Ed. Chapter: 24 Page: 422

Question 77

13650 – Serotonin 1: constricts blood vessels 2: in the blood is largely confined to the red blood cells 3: increases salivation 4: has 5 hydroxy-indoleacetic acid as a urinary metabolite

Answer 77

TFFT Serotonin is found typically in blood platelets, in the retina, in enterochromaffin cells, in the myenteric plexus and in brain neurons, but not in red blood cells (B false). It is formed in the body by hydroxylation and decarboxylation of tryptophan. However, the hydroxylase is not saturated so that an increase in dietary tryptophan can increase brain serotonin content. After release from serotonergic neurons, much of the released serotonin is returned by an active re-uptake mechanism and inactivated by monamine oxidase to form 5-hydroxyindoleacetic acid which is excreted in the urine (D true). It will constrict, or dilate, blood vessels (A true), but does not enhance salivation (C false).

Question 78

12909, 15473 – Serotonin (5-hydroxytryptamine) causes 1: constriction of some vessels 2: contraction of the ileum 3: stimulation of salivary secretion 4: stimulation of cardiac muscle

Answer 78

TTFF Refer to Guyton, 7th Ed, Ch 18, page 242; Ch 20, page 338; Ganong, 19th Ed, Ch 4, page 98-99; Ch 15, page 250-251. Serotonin is present in highest concentrations in blood platelets and in the gastrointestinal tract where it is found in enterochromaffin cells and in the myenteric plexus. When blood vessel walls are injured platelets collect at the site and stick to the injured vessel liberating serotonin to cause local vasoconstriction (A true). Serotonin contracts small intestinal muscle (B true) but has little direct effect on salivary secretion (C false) or cardiac function (D false).`

Question 79

22979 – With respect to the ovary 1: luteinising hormone is the main hormone responsible for ovulation 2: during the first trimester of pregnancy, bilateral oophorectomy may be followed by abortion 3: plasma progesterone level peaks about day 21 of a 28-day menstrual cycle 4: plasma oestrogen level peaks about day 8 of a 28-day menstrual cycle

Answer 79

TTTF Guyton 7th ed. CHAPTER: 81, 82 PAGE: 969-970, 988

Question 80

27543 – Concerning the ovary 1: luteinising hormone stimulates the secretion of oestrogen from the theca interna 2: follicle-stimulating hormone regulates the theca interna 3: plasma oestrogen level peaks about day 8 of a 28-day menstrual cycle 4: during the first trimester of pregnancy, bilateral oophorectomy may be followed by abortion

Answer 80

TFFT Guyton A, Hall J, Textbook of Medical Physiology, WB Saunders, 1996, 9th Edition; Ch 81. Both follicle-stimulating hormone (FSH) and luteinising hormone (LH) are secreted by the anterior pituitary in response to stimulation of the pituitary by gonadotropin-releasing hormone (GnRH) secreted by the hypothalamus. Ovarian function is entirely dependent on stimulation by FSH/LH. FSH, in particular, stimulates the accelerated growth of 6-12 primary follicles with rapid proliferation of granulosa cells as well as a second class of cells that form theca interna and externa. As its name suggests the development of the primary follicle to vesicular follicle is due to FSH. Both granulosa cells and theca interna cells secrete oestrogens. Granulosa cells initially have FSH receptors but later develop LH receptors. Theca interna cells have LH receptors, not FSH (2 False); and also secrete oestrogens under the stimulus of LH (1 True). LH is needed for the final development of the follicle, as well as ovulation. There is a rapid rise of both LH & FSH in the hours before ovulation. LH then seems to convert the granulosa and theca internal cells into a more progesterone-secreting type of cell. The rise and fall of the various hormones are seen subsequently in Figures 4 and 5. Plasma oestrogen levels peak near ovulation in midcycle (3 False). The progesterone secreted by ovarian corpus luteum in the second half of the menstrual cycle prepares a receptive endometrium for the fertilised ovum (Figures 4 and 5). After implantation, ongoing nutrition of this conceptus is dependent on corpus luteum secretion of progesterone, oestrogen and relaxin. After about six weeks the placenta is able to produce enough oestrogen and progesterone to maintain pregnancy. Oophorectomy before the sixth week will thus lead to abortion (4 True).

Question 81

27612 – Concerning menstruation 1: heavy periods are an unusual cause of anaemia 2: polymenorrhoea usually reflects a clotting disorder 3: stress can upset the menstrual cycle 4: intermenstrual bleeding is common and of no concern

Answer 81

FFTF Excessive menstrual loss is actually the commonest cause of anaemia in Western society (1 False). Investigations of iron deficiency anaemia must include consideration of this possibility - it can be easily overlooked by all parties. When considering abnormal menstrual loss it is best to remember that: 1 'menorrhagia' is excessive bleeding in regular cycles and tends to have a local cause in uterine fibroids, or faulty clotting. 2 'polymenorrhea' are periods that are too frequent, due usually to a disturbance of the hormones of the pituitary/ovarian axis (2 False). 3 'polymenorrhagia' is the condition of periods that are both too heavy and too frequent, usually due to a combination of the above causes. Alterations to the menstrual cycle can be due to emotional and traumatic factors acting on neuroendocrine effector pathways (3 True) emanating from the hypothalamus (Chapter 14 Ganong). Intermenstrual bleeding is a serious symptom that may be due to uterine/cervical cancer (4 False) and so must be thoroughly investigated.

Question 82

27548 – Concerning the menstrual cycle 1: new ova are formed during the proliferative phase 2: involution of the corpus luteum removes feedback inhibition on the anterior pituitary 3: follicle-stimulating hormone is essential to allow the follicle to progress to ovulation 4: thecal cells mainly form androgens

Answer 82

FTFT The formation of ova occurs during fetal development (1 False). Some 300,000 - 400,000 are present at puberty but only some 400 of these follicles will develop enough to expel their ova. The feedback regulation of ovarian function is seen well in Figure 3 below. As can be seen, involution of the corpus luteum means loss of inhibin and oestrogen which removes feedback inhibition of the anterior pituitary and allows for the next cycle to commence (2 True). The mid-cycle burst of LH is responsible for ovulation. There is a similar, but smaller, pulse of FSH which is of uncertain significance - however it is not necessary for ovulation (3 False). Androgens are produced from thecal cells (4 True).

Question 83

10084 – During the follicular phase of the menstrual cycle 1: basal body temperature progressively increases 2: progesterone levels are depressed 3: oestradiol secretion is inhibited 4: vaginal mucus is thin and alkaline

Answer 83

FTFT Ganong, 19th ed, Ch 23

Question 84

27571 – In human pregnancy 1: there is a decrease in maternal antibody production 2: maternal blood volume is lower at the 30th week compared to the 12th week 3: placental cells secrete relaxin 4: the anterior pituitary gland enlarges at least 50 per cent

Answer 84

TFTT See Ganong WF, Review of Medical Physiology, Appleton & Lange, 1999. 19th Edition and Guyton A, Hall J, Textbook of Medical Physiology, WB Saunders, 1996, 9th Edition. A number of changes occurs to the mother during pregnancy (Table 3). The enlarging uterus can also move abdominal contents around. In particular, a mobile caecum can lead to the appendix riding up out of the right iliac fossa.

Question 85

15112 – In human pregnancy 1: plasma oestriol levels decrease during the second trimester 2: oestriol is synthesised by the combined effect of foetal and placental tissue (ie by the foetoplacental unit) 3: removal of the ovaries after three months leads to abortion 4: human chorionic somatomammotropin (HCS) has some of the actions of growth hormone

Answer 85

FTFT Refer to Ganong, 19th Ed, Ch 23, page 428 and followingr

Question 86

23204 – During pregnancy the 1: plasma level of oestriol is higher at the 36th week than at the 20th week 2: secretion of FSH and LH into the maternal blood is increased 3: maternal blood volume is higher at the 30th week than it is at the 6th week 4: plasma level of free thyroxine is increased and maternal hyperthyroidism is present

Answer 86

TFTF Guyton 8th Ed. Chapter: 82 Page: 919-922 Ganong 15th Ed. Ch. 23 P. 422 4: level of thyroid binding globulin raise during pregnancy --> # of free T3/T4 remains the same

Question 87

27581 – During pregnancy 1: increased aldosterone production, combined with marked oestrogen secretion is the cause of fluid retention in pregnancy 2: maternal cardiac output is 30-40 per cent above normal at term 3: maternal thyroxine production increases by some 50 per cent 4: the position of the mother's appendix can be pushed into the right upper quadrant

Answer 87

TFTT See Guyton A, Hall J, Textbook of Medical Physiology, WB Saunders, 1996, 9th Edition. Pregnant women have a two-fold increase in secretion of aldosterone, which, together with the increased oestrogen secretion, causes fluid retention (1 True). Cardiac output increases to a level 30- 40% above normal by the 27th week, but thereafter falls to near normal by the end of the pregnancy (2 False). The thyroid gland enlarges during pregnancy by upwards of 50%, with corresponding increase in thyroxine production (3 True). The enlarging uterus can displace other abdominal viscera, so that the position of the appendix can be in the right upper abdominal quadrant (4 True).

Question 88

27576 – Concerning placental function 1: the placental trophoblast prevents rejection of the 'foreign tissue fetus' by the mother 2: secretion of human chorionic gonadotropin is vital to prevent expulsion of an implanted ovum 3: hCG-b cannot be detected in the blood until 18 days after conception 4: secretes human chorionic somatomammotropin

Answer 88

TTFT See Ganong WF, Review of Medical Physiology, Appleton & Lange, 1999. 19th Edition (1 and 3) and Guyton A, Hall J, Textbook of Medical Physiology, WB Saunders, 1996, 9th Edition (2 and 4). The placenta develops from the trophoblast cells, as well as adjacent cells of the blastocyst and endometrium. This placental trophoblast does not express a polymorphic class of gene - instead the placental trophoblast expresses a non-polymorphic gene which does not induce maternal antibodies against the fetus (1 True). The placenta secretes a number of hormones: * Human chorionic gonadotropin (hCG) - hCG can be detected in the blood as early as six days after conception (3 False) and possibly in the urine at 14 days. The hCG prevents normal involution of the corpus luteum, thus promoting increased ovarian secretion of oestrogen and progesterone which prevents shedding of endometrium (2 True). * Human chorionic somatomammotropin (hCS) (4 True) which is lactogenic, growth stimulating and causes reduced insulin sensitivity and decreased glucose utilisation in mother. * Oestrogens. * Progesterone.

Question 89

10461 – In the breast 1: prolactin is the most important hormone for milk 'letdown' 2: milk production is facilitated after parturition because circulating oestrogen levels are maintained 3: prolactin is the most important hormone for the release of milk into the alveoli 4: progesterone is the most important hormone for duct development

Answer 89

FFTF Oestrogens are primarily responsible for duct development and progesterone for lobular development in the breast (D false). During pregnancy, prolactin levels steadily increase until term, reaching a peak at the time of parturition. Prolactin is responsible for the formation of milk and its secretion into the ducts (C true). The hormone responsible for milk 'let down' is oxytocin released in response to touching the nipples and areolae (A false). After parturition, there is an abrupt decline in circulating oestrogens and progesterone. The drop in oestrogens initiates lactation. Oestrogen antagonises the milk-producing effect on prolactin in the breast and may be given to stop lactation (B false).

Question 90

23884 – With respect to breast development and lactation 1: prolactin initiates milk secretion 2: oxytocin induces milk ejection ('let-down') 3: oestrogen stimulates duct growth 4: growth hormone alone stimulates lobule-alveolar growth

Answer 90

TTTF Guyton 7th Ed. Chapter: 82 Page: 994-995 Ganong 13th Ed. Chapter: 23 Page:378-379 4: progesterone

Question 91

22364 – Breast development in females requires 1: progesterone for lobule-alveolar growth 2: oxytocin and oestrogen for lobule-alveolar growth 3: oestrogen for duct growth 4: prolactin and no other hormones for duct growth

Answer 91

TFTF Ganong 13th Ed. CHAPTER: 23 PAGE: 378

Question 92

22369 – With respect to the ovarian hormones 1: during the luteal phase of the menstrual cycle urinary pregnanediol excretion normally exceeds 2mg/24 hours 2: plasma oestrogen level peaks about 24-48 hours preceding ovulation 3: progesterone decreases the response of the uterus to oxytocin 4: progesterone induces secretion of thick, tenacious and cellular cervical mucus

Answer 92

TTTT Ganong 13th ed. Chapter: 23 Page: 367-369 Guyton 7th ed. Chapter: 81 Page: 969; 975

Question 93

27561 – Oestrogens 1: increase the amount of uterine muscle and content of contractile proteins 2: are largely responsible for breast enlargement in puberty 3: cause increased secretion of thyroid-binding globulin 4: are the primary cause of growth of pubic and axillary hair

Answer 93

TTTF See Ganong WF, Review of Medical Physiology, Appleton & Lange, 1999. 19th Edition and the Effects of Oestrogen Table . Oestrogens are secreted by the granulosa cells of the ovarian follicles, corpus luteum and the placenta. Their essential action is to stimulate growth and cell proliferation of the sex organs.

Question 94

15503 – Oestrogens 1: increase secretion of angiotensinogen 2: reach peak levels during the mid-follicular phase of the menstrual cycle 3: sensitise the myometrium to oxytocin 4: inhibit contractile proteins in uterine muscle

Answer 94

TFTF Refer to Ganong, 19th Ed, Ch 23, page 419 and following

Question 95

27566 – Progesterone 1: is secreted by both placenta and corpus luteum 2: stimulates development of breast lobules and alveoli 3: induces secretion of thick, viscous and cellular cervical mucus 4: decreases excitability of myometrial cells

Answer 95

TTTT Progesterone is secreted by the corpus luteum and placenta (1 True), and to a minor degree the follicle.

Question 96

13373 – S: Production of progesterone by the corpus luteum is not necessary during the last half of pregnancy because R: during the last half of pregnancy the placenta secretes sufficient amounts of progesterone to maintain pregnancy

Answer 96

S is true, R is true and a valid explanation of S After fertilisation the corpus luteum in the ovary fails to regress. Instead it enlarges in response to the secretion of placental human chorionic gonadotropin (HCG), and secretes oestrogens and progesterone. After six to eight weeks HCG secretion subsides and the corpus luteum starts to regress. Ongoing oestrogen and progesterone production is then taken over by the placenta (S and R are both true and R is a valid explanation of S.)

Question 97

27617 – Concerning post-menopausal vaginal bleeding 1: exogenous oestrogens are a possible cause 2: uterine cancer needs to be ruled out 3: urethral caruncle is very rarely a factor 4: post-menopausal vaginal bleeding can be caused by colon cancer

Answer 97

TTFT Exogenous oestrogens influence the endometrial lining causing proliferation of the endometrial stroma and glandular proliferation with shedding of this thickened layer is likely with any drop in the level of oestrogen. Such 'post-menopausal' bleeding is a common effect of female 'hormone replacement therapy' (HRT) (1 True). Uterine cancer is a very important diagnosis and a common cause of post-menopausal bleeding (2 True). About 25% of post-menopausal bleeding is due to a genital malignancy. A urethral caruncle is an inflammatory lesion that occurs (quite commonly) at the external urethral meatus, usually in elderly women. It is a highly vascular lesion with young connective tissue and a variably present epithelial covering of transitional or squamous cells. It is equally important to examine the external genitalia thoroughly as cancer or infection externally can be interpreted as blood of vaginal origin. Caruncle is an important and relatively frequent cause of vaginal bleeding (3 False). Due to the relatively thin 'window' of the posterior vaginal fornix it is possible, although unusual, for an abdominal cancer to grow through into the vagina to cause bleeding (4 True). Due to its thick muscular wall, full thickness infiltration of the uterus is exceedingly uncommon

Question 98

10079 – With regard to the testis 1: normal spermatogenesis takes place under the effect of F.S.H. (Follicle Stimulating Hormone) alone 2: Sertoli cells secrete inhibin which has a negative feedback effect on the anterior pituitary 3: testosterone from Leydig cells inhibits the release of F.S.H. from the anterior pituitary 4: testosterone inhibits luteinising hormone secretion at the level of the hypothalamus

Answer 98

FTFT Ganong, 19th ed, Ch 23. Please note that testosterone has no effect on FSH except in large doses. See Ganong, 19th ed, pages 412-413. The major control of FSH at the pituitary level is feedback by the hormone inhibin from the Setoli cells of the seminiferous tubules. Large doses of testosterone do indeed inhibit GnRH release at hypothalamic level, thereby reducing the drive on secretion of both LH and FSH. However in terms of the "big picture" on control of gonadotrophin secretion, LH is mainly under negative feedback control by testosterone, thus stabilising testosterone levels, while FSH is mainly under control of inhibin, thereby stabilising spermatogenesis. The answer is thus somewhat of a judgement call. This type of question, where there is merit on both sides, tends to get trickier the longer you look at it.

Question 99

22354 – Testosterone 1: is the most androgenic sex steroid 2: circulates in the plasma mainly bound to protein 3: has no effect on spermatogenesis 4: is synthesized from cholesterol in the Leydig cells

Answer 99

FTFT Ganong 19th Edition CHAPTER: 23 PAGE: 409.

Question 100

23949 – Testosterone is 1: elaborated in the male embryo especially during 7th - 12th weeks 2: almost absent in the male up to the age of about 10 years 3: an inhibitor of LH production working through the hypothalamus 4: necessary for normal spermatogenesis

Answer 100

TTTT Guyton 7th ed. CHAPTER: 80 PAGE: 960-964

Question 101

22379 – Steady state compensation of a poorly clad individual during exposure to a cold environment is achieved by 1: reduced heat loss by radiation 2: mobilization of free fatty acid 3: increased metabolic activity in muscles 4: increased catecholamine secretion

Answer 101

TTTT

Question 102

20181 – S. By keeping a patient with a severe burn in a room temperature in the range 27 – 30oC, the excessive metabolic rate is reduced BECAUSE R. heat losses are minimized by raising the room temperature

Answer 102

S is true, R is true and a valid explanation of S Ganong 13th Ed. Chapter: 17 Page: 230-232 Chapter: 14 Page: 206-207

Question 103

20919 – S. Temperature regulation in a dry environmental temperature of 38oC is obtained primarily by skin vasodilatation BECAUSE R. dilatation of skin vessels allows skin temperature to approach core temperature

Answer 103

S is false and R is true Guyton 7th ed. CHAPTER: 72 PAGE: 854

Question 104

21853 – With regard to sweating 1: when sweating is minimally stimulated, sweat urea is usually very concentrated 2: maximal sweat production in a heat-acclimatized person is approximately 2L/hr 3: heat-acclimatised persons secrete less sodium in their sweat by an aldosterone-dependent mechanism 4: potassium concentration in sweat is greater than in plasma

Answer 104

TTTT Guyton Page: 800

Question 105

20391 – S. A man will get colder in water at 25oC than in air at the same temperature BECAUSE R. the thermal conductivity of water is greater than that of air

Answer 105

S is true, R is true and a valid explanation of S Guyton 7th Ed. Chapter 72 Page: 850-851

Question 106

9963, 12838 – A patient suffering from a feverish illness 1: tends to feel coldest while his central body temperature is rising 2: shows marked body temperature swings with swings in environmental temperature 3: has a raised basal metabolic rate 4: sweats only when his central body temperature is rising

Answer 106

TFTF Ganong, 19th ed, Ch 14. When fever occurs in man the thermoregulatory mechanism behaves as if the body temperature has been set a higher level. The temperature receptors then signal the actual temperature below the set point. Thus the patient will feel coldest when the central body temperature (A true) is rising and will have a raised metabolic rate (C true). Because the core temperature is set at a higher level, marked swings do not occur with changes in environmental temperature (B false). Sweating will occur whenever the temperature is elevated, not only when it is rising (D false).

Question 107

12500 – Of the types of cellular lipid, the chief one that produces heat and aids in thermoregulation is A. lipoprotein B. brown fat C. saturated fat D. neutral fat E. depot fat

Answer 107

B Brown fat is a special type of fat formed between the scapulae of human infants, and some animals, but is not present in adult humans. This fat has a high rate of metabolism and therefore aids in thermoregulation in the infant (B true). Lipoprotein is a structural fat and, although saturated, neutral and depot fats are rich sources of energy but do not contribute directly to thermoregulation (A, C, D and E false).