Case Study

1. Daniel’s body temperature rises above normal during the surgery (hyperthermia). How does skeletal muscle tissue contribute to body temperature?

Skeletal muscles contract which help in maintaining body temperature as their contractions coverts energy into heat. Skeletal muscle uses ATP to contract. ATP is broken down into ADP and P, which in return, releases energy (heat).

2. During malignant hyperthermia, there is an increased amount of calcium released into the sarcoplasm of skeletal muscle cells. What organelle stores calcium in muscles cells?

The organelle that stores calcium in muscle cells is the sarcoplasmic reticulum.

3. Describe the events that must occur in the muscle cell before calcium is released from this organelle.

1: Action potential transmitted across sarcolemma

2: Action potential transmitted into muscle cell through T-tubules

3: Action potential transmits impulse to ryanodine receptors on the terminal cisternae of the SR to release calcium

4. Jaw muscle contraction (masseter spasm) is one of the key physical findings seen in Daniel’s case of malignant hyperthermia. Explain how calcium functions to cause contraction of a skeletal muscle cell.

Calcium binds to troponin which uncovers the myosin-head binding sites. Then it bind to actin at those sites and forms a cross-bridge. Lastly, ATP generates a series of steps on the myosin head for contraction.

5. Dr. Williams notes that Daniel’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?

Glycolysis and the TCA cycle.

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 Daniel’s body...