1. David’s body temperature rises above normal during the surgery (hyperthermia). How does skeletal muscle tissue contribute to body temperature?
2. During malignant hyperthermia, there is an increased amount of calcium released into the sarcoplasm of skeletal muscle cells.
a. What organelle stores calcium in muscles cells?
b. Describe the events that must occur in the muscle cell before calcium is released from this organelle.
3. Jaw muscle contraction (masseter spasm) is one of the key physical findings seen in David’s case of malignant hyperthermia. Explain how calcium functions to cause contraction of a skeletal muscle cell.
4. Dr. Hodges notes that David’s exhaled carbon dioxide levels are elevated. List all the metabolic pathways that function to synthesize ATP for skeletal muscle contraction. Which of these pathways produces carbon dioxide as a by-product?
5. Malignant hyperthermia causes a hypermetabolic state in skeletal muscle, which is triggered by high demands for ATP during uncontrolled muscle contractions.
a. What is the role of ATP in cross bridge cycling?
b. What is the role of ATP in maintaining calcium concentration gradients?
6. Dantrolene is the only drug available to treat malignant hyperthermia. It works by inhibiting calcium channels of the terminal cisterns of the sarcoplasmic reticulum. Explain how this inhibition helps to terminate skeletal muscle contraction. What effect would this have on David’s body temperature?
Bonus Assignment: Concept Review (5pts)
*Please use another color for your answers*
1. Neuromuscular Junction (NMJ):
Fill in the sequence of major events at the neuromuscular junction when an action potential has arrived at the axon terminal of a NMJ (summarize in a way that you can easily remember for the exam).
2. Excitation-Contraction Coupling: (answer in your own words)
A. What happens to the axon potential that arrives at the sarcolemma?
B. What happens once the action potential arrives at the terminal cisternae of sarcoplasmic recticulum?
C. What happens once calcium ions are released into the sarcoplasm?