**Laboratory 8: Muscle Lecture & Case Study**

**Rigor Mortis (Muscle Contraction)**

Braude, S., Goran, D., and Maxfield, S. 2011. *Case Studies for Understanding the Human Body*, 2nd Edition. Boston: Jones and Bartlett Publishers. pp. 141-145.

Emma Louise, RN, started her morning rounds in Mrs. Weitzel's room. Mrs. Weitzel was to have surgery later in the week, and Emma had an order to draw some blood for lab work. Because the patient appeared to be sleeping, Emma took her time tidying up the room. As Emma approached the side of the bed, Mrs. Weitzel suddenly moved her leg. Emma looked over at Mrs. Weitzel and noticed she was not breathing. She pressed the code-blue button and checked Mrs. Weitzel's airway to begin artificial respiration and cardiopulmonary resuscitation (CPR). Several of Emma's colleagues rushed into the room with the crash cart. Mrs. Weitzel was not breathing, was ashen in color, and was very cold. The emergency team could not find a pulse or a heartbeat, and they could not detect respiration. On closer examination, the resident found every joint in her body was stiff.

Just then Mrs. Weitzel's son, Josh, entered the room. He had come to visit his mother and was shocked to see so many people in her room. He couldn't believe his ears when the resident declared his mother deceased. Josh remembered that Emma had been taking care of her and demanded that she explain what had happened. Emma told Josh that she had entered the room half an hour ago and let Mrs. Weitzel sleep while she tidied up the room. Mrs. Weitzel's son insisted that Emma was negligent because she was standing right there while his mother died. He got so worked up that he even accused Emma of killing his mother. Emma was so upset that she couldn't respond.

Later that week, a board of inquiry convened at the insistence of Mrs. Weitzel's son. Emma was accused of negligence in the care of her patient, but you know this is not the truth. Help Emma explain why Mrs. Weitzel must have been dead before she entered the room.

**QUESTION 2**

After hearing this explanation, Mrs. Weitzel's son jumped up and complained that tiny molecules of actin and myosin could not be responsible for moving his mother's leg. In response to Josh's claim, explain how actin and myosin are bundled into myofibrils and sarcomeres so that their action is summed to generate significant force in a muscle. What is the overall purpose of the bundling of muscles?

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**QUESTION 4**

Emma's attorney, Mr. Martin, insists that Mrs. Weitzel was dead before Emma even entered the room.

a. If Mrs. Weitzel was already dead, how could her leg move? (An action potential did not come down the motor nerves that stimulate the tensor fasciae latae.) (2 points)

b. Which structures must have become leaky for contraction to occur? (1 point)

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**QUESTION 5**

Which physiological process occurred in Mrs. Weitzel's dead body to cause her muscles to lock in the contracted state?

a. How is it relevant that Mrs. Weitzel was extremely underweight and that Emma had to coax her daily to eat anything at all?

b. How do we usually store energy and oxygen in muscle cells?

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**QUESTION 6**

Take the role of Emma's lawyer, Mr. Martin, at the board of inquiry. Summarize for Mrs. Weitzel's son what must have happened when Emma entered the room. Leave it to the pathologist to explain the real cause of death.