Case 1: During her first visit to a Caribbean country, MargaretMcKenzie, a 35 year-old woman, decided to try snorkeling over alocal coral reef. Although she enjoyed the· fascinating plants andfishes, she found the taste of salt water unpleasant and was havingtrouble maintaining her orientation and position in the waves.Margaret lifted her head up and noticed that she was driftingfurther and further from shore. With a start, she realized that thetide was going out. She could hear her breath whistling through hersnorkel, and she noticed that her breathing rate was fairly fastand getting faster. Shortly thereafter, she noticed that her hearthad begun to pound. Margaret decided to swim in to shore. Althoughnot usually a strong swimmer, Margaret found unexpected reserves ofstrength that enabled her to swim against the outgoing tide. Whenshe arrived on the beach she was pale, breathing hard, and herheart was racing. Over the next few moments her color, and herheart and respiratory rates began to return to normal.
Case 2: Matthew was a first-year student in a medicalillustration program. As part of his education, he was required toattend an autopsy with his class. This was to be his firstexperience viewing a dead human body, and he was apprehensive aboutit for days in advance. As he was attempting to sketch the greatvessels of the heart, he noticed that his breathing rate was fastand getting faster. At the same time, he noticed that his heart hadbegun to race, that he was sweating despite the cool temperature,and that he was feeling lightheaded and nauseous. His professor,noticing that Matthew was pale and his pupils were dilated, led himto a chair outside the autopsy room. She handed Matthew a paper bagand recommended that he breathe into it for a few minutes. SoonMatthew's lightheadedness and nausea began to subside and hisrespiratory and heart rates began to return to-normal.
Guided questions for Case 1.
1. Describe the \"Fight or Flight\" reaction?
Phase 1: What general CNS structure is responsible forperception of fear and how are activating signals sent to the body(targets)?
Phase 2: Discuss neural and endocrine response to the activationof the fight or flight response.(bonus- Is there a difference inhalf-life of substances? If so, which one lasts longer?)
Phase 3. Describe effects on muscle, liver, heart and lungs.Bonus (what other changes may occur?
2. Describe mechanisms responsible for Margaret's circulatorychanges e.g. cardiac and vascular; receptors and signalingpathway?
3. How can Margaret's increase in energy be explained?
4. What mechanisms caused Margaret's respiratory changes?
Guided Questions for Case 2:
5. Why was Matthew pale and sweating e.g. relate autonomics tocontrol of cutaneous blood flow?
6. Why did Matthew feel lightheaded hint- breathing rate andCO2?
7. How did breathing into a paper bag relieve Matthew'ssymptoms?
