Anatomy and Physiology Comprehensive Final Essay

2054 Words9 Pages
The 2000-Meter Row: A Case in Homeostasis
Adapted from the National Center for Case Study Teaching in Science* by Nathan Strong

At the start 1. Recall that Jim's heart and respiratory rate are increased, he was sweating and that his mouth was dry before the raise began. Explain what is happening to his autonomic nervous system (including which division is the most active) and specify exactly how those ANS responses are creating the symptoms noted. What changes do you think are occurring in the digestive and urinary systems at this time? (8 points)

In his autonomic nervous system, the sympathetic division was the most active before and during the race because it is what prepares your body for extra somatic activity. It activated
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Now, pick one of those muscles and trace their control from the appropriate brain structure all the way to the NMJ. Be sure to include all intermediate structures, synapses, plexuses and nerves.
(8 points)

Movement of the deltoid begins in the cerebrum of the brain, but more specifically: in the frontal lobe, the premotor cortex is relaying instructions to the primary motor cortex. The primary motor cortex contains the upper motor neurons whose axons will travel down the pyramids of the medulla oblongata and synapse on lower motor neurons in the anterior gray horns of spinal cord segments C5-C6. From there, the ventral rami of spinal nerves C5-C6 form the superior trunk of the brachial plexus, which splits into two divisions. We will follow the posterior division that supplies to extensor muscles. This posterior division then runs into the posterior cord from which the axillary nerve is derived. The axillary nerve’s motor end innervates the deltoid through its neuromuscular junction.

4. Rowing full speed is putting maximum demands on Jim's muscles. What metabolic process is providing most of the energy for Jim’s muscles at this point and why do Jim's muscles feel like they are burning? (5 points)

As Jim’s muscles are at maximum demand, his mitochondria are unable to produce the needed ATP through aerobic respiration because oxygen is unable to diffuse fast enough into his muscle fibers. At this time anaerobic
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