front 1 A nude hiker in dry air can maintain core temperature at
ambient: | back 1 D. 55°F to 130°F |
front 2 During exposure to cold wind, which temperature changes most? | back 2 B. Skin temperature mostly |
front 3 Heat production is primarily a by-product of: | back 3 C. Metabolism |
front 4 Total heat loss rate depends mainly on: | back 4 B. Core→skin conduction, skin transfer |
front 5 Subcutaneous fat reduces heat loss mainly by acting as: | back 5 D. Heat insulator |
front 6 Fat is an effective insulator because it conducts heat: | back 6 A. One third as readily |
front 7 In fingers and ears, arterial blood can enter venous plexus
via: | back 7 C. Arteriovenous anastomoses |
front 8 Skin serves as a controlled “radiator” mainly through: | back 8 D. Blood flow to skin |
front 9 Heat delivery to skin by blood is controlled chiefly by: | back 9 A. Arteriolar and AV constriction |
front 10 At room temperature, ~60% of heat loss occurs via: | back 10 C. Radiation |
front 11 Normally, direct conduction to solid objects accounts for
about: | back 11 A. 3% |
front 12 Under normal conditions, conduction to air accounts for
about: | back 12 D. 15% |
front 13 Even without sweating, insensible water loss is about: | back 13 C. 600–700 mL/day |
front 14 Heat exposure triggers sweating via stimulation of the: | back 14 D. Anterior preoptic hypothalamus |
front 15 Sweating commands travel from hypothalamus mainly through: | back 15 B. Sympathetic outflow to skin |
front 16 Sweat glands are innervated by sympathetic fibers that are: | back 16 C. Cholinergic |
front 17 The neurotransmitter released at sweat glands is: | back 17 A. Acetylcholine |
front 18 A sweat gland’s secretory portion is best described as: | back 18 D. Deep subdermal coiled tubule |
front 19 Sweat reaches skin surface through the: | back 19 C. Duct through dermis/epidermis |
front 20 Heat loss from core to skin is limited most by: | back 20 A. Core-to-skin conduction rate |
front 21 Heat transfer from skin to surroundings occurs by all EXCEPT: | back 21 C. Metabolism |
front 22 A patient with strong cutaneous vasoconstriction will have: | back 22 D. Reduced heat delivery to skin |
front 23 With slight sweat stimulation, Na⁺ and Cl⁻ are: | back 23 C. Reabsorbed in duct |
front 24 At low sweating rates, urea/lactate/K⁺ are: | back 24 D. Highly concentrated |
front 25 Core temperature regulation relies mainly on: | back 25 B. Hypothalamic feedback control |
front 26 The main “heat center” region is: | back 26 A. Anterior hypothalamic-preoptic area |
front 27 In the preoptic area, cold-sensitive neurons are: | back 27 C. About one third as many |
front 28 Heat-sensitive neuron firing with +10°C increases: | back 28 B. 2- to 10-fold |
front 29 The preoptic area can function as a: | back 29 D. Thermostatic control center |
front 30 TRP thermal sensors are a family of: | back 30 A. Cation channels |
front 31 TRP thermal channels are found mainly in: | back 31 B. Somatosensory neurons, epidermal cells |
front 32 Whole-body skin chilling immediately increases: | back 32 C. Shivering heat production |
front 33 If sweating is occurring, chilling will: | back 33 D. Inhibit sweating |
front 34 Chilling reduces heat loss primarily by: | back 34 B. Promoting skin vasoconstriction |
front 35 Deep temperature receptors are found mainly in: | back 35 A. Spinal cord |
front 36 Deep temperature receptors also exist in/around: | back 36 D. Great veins upper abdomen/thorax |
front 37 Preoptic temperature signals are transmitted to the: | back 37 C. Posterior hypothalamus |
front 38 First major heat-loss response to overheating is: | back 38 A. Skin vasodilation |
front 39 Skin vasodilation during overheating occurs via: | back 39 D. Inhibition of posterior sympathetic centers |
front 40 The second major heat-loss mechanism is: | back 40 C. Sweating |
front 41 The third major heat-loss response is decreased: | back 41 B. Heat production |
front 42 Decreased heat production occurs by inhibiting: | back 42 A. Shivering and chemical thermogenesis |
front 43 When the body is too cold, the first response is: | back 43 C. Skin vasoconstriction |
front 44 Cold-induced vasoconstriction is caused by: | back 44 B. Stimulated posterior sympathetic centers |
front 45 Piloerection refers to: | back 45 D. Hairs standing on end |
front 46 Piloerection is produced by contraction of: | back 46 A. Arrector pili muscles |
front 47 Increased thermogenesis in cold occurs via: | back 47 C. Shivering, SNS, thyroxine |
front 48 The primary shivering motor center lies in: | back 48 B. Dorsomedial posterior hypothalamus |
front 49 Rapid catecholamine-driven metabolic heat is called: | back 49 C. Chemical thermogenesis |
front 50 Chemical thermogenesis magnitude is proportional to: | back 50 A. Brown fat amount |
front 51 Mitochondrial uncoupling protein is also called: | back 51 D. Thermogenin |
front 52 Brown fat thermogenesis is triggered mainly by: | back 52 B. Sympathetic norepinephrine |
front 53 Cooling the anterior preoptic area increases: | back 53 C. TRH production |
front 54 Thyroxine increases chemical thermogenesis mainly by: | back 54 A. Raising cellular metabolism |
front 55 Temperature control “feedback gain” equals: | back 55 B. ΔEnv/ΔCore minus 1 |
front 56 Neck spinal transection above sympathetic outflow impairs: | back 56 C. Skin blood flow, sweating control |
front 57 Substances raising hypothalamic set point are: | back 57 D. Pyrogens |
front 58 Pyrogens commonly arise from: | back 58 A. Bacteria and degenerating tissues |
front 59 Direct hypothalamic pyrogens immediately: | back 59 B. Raise set point |
front 60 Bacterial products are phagocytized mainly by: | back 60 D. Leukocytes, macrophages, NK cells |
front 61 “Leukocyte pyrogen” is also called: | back 61 C. IL-1 |
front 62 IL-1 causes fever primarily by inducing: | back 62 B. Prostaglandin E2 |
front 63 Blocking prostaglandin formation will: | back 63 A. Reduce or abolish fever |
front 64 Prolonged high temperature can result from: | back 64 C. Hypothalamic compression by tumor |
front 65 Heatstroke symptoms are worsened by: | back 65 D. Circulatory shock from sweating |
front 66 Hyperpyrexia fatal pathology includes: | back 66 C. Hemorrhages, parenchymal degeneration |
front 67 Artificial cooling is used during: | back 67 B. Heart surgery to stop heart |
front 68 “Nonshivering thermogenesis” equals: | back 68 C. Chemical thermogenesis |
front 69 Sympathetic stimulation raises metabolism mainly via: | back 69 A. Norepinephrine and epinephrine |
front 70 Brown fat heat production rises because UCP: | back 70 B. Uncouples oxidative phosphorylation |
front 71 Infant brown fat is found mainly in: | back 71 D. Interscapular space |
front 72 Cooling preoptic area increases TRH, leading to: | back 72 A. Increased thyroxine release |
front 73 Thyroxine increases thermogenesis by: | back 73 C. Increasing cellular metabolic rate |
front 74 Poor thermoregulation after neck transection occurs because: | back 74 B. Hypothalamus loses sweat control |
front 75 A classic bacterial pyrogen example is: | back 75 C. Lipopolysaccharide endotoxin |
front 76 Aspirin reduces fever mainly by: | back 76 B. Inhibiting prostaglandin synthesis |
front 77 Hypothalamic compression causing hyperthermia is due to: | back 77 A. Brain tumor pressure |
front 78 Sudden set point increases can be triggered by: | back 78 C. Dehydration, pyrogens, tissue damage |
front 79 Hyperpyrexia damages tissues especially in the: | back 79 B. Brain |
front 80 Slight sweat stimulation causes low NaCl because duct: | back 80 D. Near-complete NaCl reabsorption |
front 81 At low sweating rates, urea/lactate/K become concentrated
because: | back 81 A. Water reabsorbed, solutes retained |
front 82 Deep temperature receptors are also found in: | back 82 C. Abdominal viscera |
front 83 Preoptic temperature signals are relayed into the: | back 83 B. Posterior hypothalamus |
front 84 Shivering center is normally inhibited by: | back 84 D. Anterior preoptic heat center |
front 85 Chemical thermogenesis increases metabolism via: | back 85 A. Sympathetic stimulation or catecholamines |
front 86 Poor thermoregulation after neck transection occurs because
hypothalamus can’t control: | back 86 D. Skin blood flow and sweating |