1014MSC QB 4 Questions

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Jun 5, 2024

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Quiz Buster 4 1014MSC: Cells, Tissues & Regulation Trimester 2 2023 Instructions: 1. This practice exam contains 50 questions, including a mix of MCQ, SAQ, T/F, fill in the blank & matching activities. 2. You have 60 minutes to complete the exam buster. 3. Each question is worth 1 mark each. 4. Attempt all questions and choose only one option per multiple choice question. 5. Read each question and then choose the best or most correct answer. Please note that this exam buster does not necessarily represent the format or the types of questions that you will meet in your official exam. It has been prepared by your PASS leaders who are not privy to the official exam and is simply offered as a revision tool.

2 1. In homeostasis, what is the role of negative feedback mechanisms? a) Amplify deviations from the set point b) Maintain deviations from the set point c) Reduce deviations from the set point d) Ignore deviations from the set point 2. In a thermostat-controlled heating system, if the temperature in a room rises above the set point, what will the thermostat do? a) Decrease the heater's output b) Increase the heater's output c) Maintain the heater's output d) Shut off the heater completely 3. In a negative feedback loop, what is the role of the effector? a) To detect deviations from the set point b) To transmit information to the sensor c) To initiate corrective responses to counteract deviations from the set point d) To set the initial conditions of the system 4. Oscillation about a set-point for homeostatic variables occurs: a) In all non-biological and all biological homeostatic systems b) Only in artificial or non-biological homeostatic systems c) Only in biological systems that are poorly controlled d) Only in biological system that are well controlled 5. Set point is the value toward which the system is returned if a disturbance is detected. a) True b) False 6. Calculate the gain of the following systems and determine which is a more efficient homeostatic system: System 1: Callum, who generally has a temperature of 37°C, went to a sauna where his temperature was expected to rise to 40°C, although his temperature only rose to 37.4°C System 2: Beth, who generally has a temperature of 36.8°C, also went to the same sauna where her body temperature was expected to rise to 40°C, although her temperature only rose to 37°C a) Gain 1 = 6.5; Gain 2 = 15; System 2 is a more effective homeostatic system b) Gain 1 = 7.5; Gain 2 = 15; System 1 is a more effective homeostatic system c) Gain 1 = 6.5; Gain 2 = 16; System 1 is a more effective homeostatic system d) Gain 1 = 7.5; Gain 2 = 16; System 2 is a more effective homeostatic system

3 7. What is the recommended course of action for someone with hyperpyrexia? a) Immersion in ice-cold bath b) Immersion in hot bath c) Immersion in lukewarm bath d) Eat some ice 8. Briefly describe the thermoregulatory role of the following structures observed in the epidermis: erector pili muscles, sweat glands, hypodermal adipose tissue, superficial blood vessels, and naked nerve endings. Erector pili muscle: contract in response to cold or emotional stress, causing hair follicles to stand upright, trapping an insulating layer of air close to the skins. Sweat glands: produce sweat when hot which promotes evaporation causing cooling effect when its hot, helping to regulate temperature. Hypodermal adipose tissue: is a fat and therefore insulates which will help reduce heat loss and help maintain body temperature. Superficial blood vessels: Vasodilation of these vessels allows more blood flow near the skin’s surface, facilitating heat dissipation when the body is too warm. Vasoconstriction means less heat will be lost this way thereby maintaining the core temperature of the body. Naked nerve endings: these receptors in the skin detect temperature changes and send signals to the hypothalamus to initiate appropriate thermoregulatory responses. 9. Someone suffering from heat stroke is likely to a) Be sweating profusely b) Have a core temperature above 40°C c) Have a surface temperature higher than the core temperature d) All the above 10. Where are deep body receptors located? a) CNS b) Nerve endings c) In the muscles and glands d) In the Hypothalamus 11. Which terms are the effectors in the physiological feedback system in the body? a) Glands b) Muscle System c) Nervous System d) Both a and b

4 12. If you are becoming increasingly cold, that is, tending toward hypothermia, which is the most crucial corrective response? a) Sweating less b) Sending blood from the core to the periphery c) Shivering d) Increased urine production 13. Explain how blood clotting and uterine contractions during childbirth both involve positive feedback loops and the duration of these. Blood clotting: when a blood vessel is injured , a positive feedback loop involving platelet activation and the release of clotting factors results in the rapid formation of a blood clot. Once the clot is formed, the feedback loop is inhibited , and the clotting process stops. The duration is relatively short, and the clotting process us self-limiting. Uterine contraction during childbirth: uterine contractions are also regulated by a positive feedback loop. Contractions causes the release of oxytocin, which further stimulates contraction. This loop continues until the baby is delivered. The duration of the uterine contractions during childbirth is longer and ends with the birth of the baby. Both processes involve positive feedback to achieve specific physiological goals but are tightly controlled to avoid excessive responses. 14. Fill in the blanks: A fever is an example of a positive feedback loop. We shift the hypothalamic set point higher than normal. Why? Because it allows for chemical reactions to occur more quickly, zinc + iron are sequestered by the liver, and infectiousness of microbes are reduced . The body reacts as if it were too cold . We begin to preserve and generate heat until body temperature is increased to elevated set point. The immune response fights, wins, ends, and normal temperature point is reset . 15. Which of the following is incorrect regarding heat stroke? a) Core temperature exceeds >40 degrees b) Sufferers are likely to have clammy, dry skin c) Their surface temperature may not be increased d) Heat-loss mechanisms are still functional 16. Which of the following is not a symptom of heat exhaustion? a) Elevated core body temperature b) Reduced sweating c) Dehydration d) Seeking shade or fluid 17. Positive feedback loops are always associated with disease: a) True b) False 18. Which of the following is not an example of positive feedback?

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