Question 1:
Lin is a 21 year old university student who is involved in a car accident on her way to work. She has a severe laceration to her right thigh, and has lost a lot of blood.
Using your knowledge of the regulation of blood pressure, answer the following questions.
Part A. Explain the physiological mechanisms that will maintain Lin’s mean arterial pressure in the seconds to minutes after the accident. (3 marks)
Part B. Explain the physiological mechanisms that will act to return Lin’s mean arterial pressure to normal levels in the days to weeks after the accident. (2 marks)
Question 2:
Albert is hiking in the Canadian Rockies when they are startled by a bear, activating their ‘fight or flight’ response.
Using your knowledge of autonomic control of the cardiovascular system, answer the following questions.
Part A. Explain how activation of the sympathetic nervous system affects heart rate. (2 marks)
Part B. Albert’s cardiac output will also be altered in this situation. Explain the physiological mechanisms that cause this change in cardiac output. (3 marks)
Question 3:
Joseph Wong, aged 69-year-old, is admitted to hospital with shortness of breath.? He has chronic obstructive pulmonary disease (COPD) due to smoking. He stops breathing when he is given pure oxygen through a nasal tube.
Part A. What is the normal stimulus for breathing and what normally detects this stimulus? (1.5 marks)
Part B. Why did Joseph stop breathing when he was given pure oxygen through a nasal tube? Explain your reasoning. (2 marks)
Part C. Once Joseph recovers, the doctor assesses his respiratory function. Explain whether Joseph’s minute ventilation or alveolar ventilation will give a better indication of his respiratory function. (1.5 marks)
Question 4:
Erik Foran, aged 46, contracted a bacterial infection that causes the loss of type II alveolar cells. The doctor explains to his family that the subsequent collapse of the alveoli has caused a physiological shunt.
Part A. Why does the loss of type II alveolar cells cause the collapse of alveoli and a physiological shunt? In your answer, explain what a physiological shunt is, and why it is a problem. (3 marks)
Part B. Erik recovers but has pulmonary fibrosis where the lung cannot expand to its full capacity. Compared to a normal FEV1/FVC ratio, what do you expect will happen to Erik’s FEV1/FVC ratio? Explain why this ratio is changed. (1 mark)
Part C. One of side effects of Erik’s medication is the inhibition of the carbonic anhydrase enzyme. Explain the effect of inhibiting carbonic anhydrase. (1 mark)