John is 28 years old and has been an active amateur athlete all his life. He has however had a number of nasty viral illnesses in the last 8-10 months. He now complains that he can no longer train like he could just last year. After 10-15 minutes jogging his legs become weak and he has to sit down on a bench despite not felling tired or out of breath. After a few minutes he can continue but the pattern repeats again after another half mile. He has also noted that reading even in the early afternoon when well rested the page gets blurry after 10 minutes. His eye doctor did a refractory and said he does not need glasses and refers him to internal medicine.
1. Based on the symptoms John most likely has:
A. Chronic fatigue syndrome.
B. Myasthenia Gravis
C. Atherosclerosis of the femoral artery.
E. Rheumatoid Arthritis.
2. The doctor has John read a series of small print paragraphs until the text begins to blur. He then administers a drug which immediately restores John's visual clarity. The drug acts by increasing:
A. Muscle glycogen.
B. Acetylcholine in the neuromuscular junction.
C. Extracellular calcium concentrations.
D. The number of recruited motor neurons.
E. Available muscle creatine phosphate..
3. A muscle biopsy would demonstrate that John has:
A. Peripheral neuropathy.
B. Severe narrowing of his peripheral arteries.
C. Fewer than normal motor end plate acetylcholine receptors.
D. Impaired muscle glycogen metabolism.
E. Excess intramuscular fatty deposits.
4. Subsequent blood work will demonstrate that John has:
D. Auto antibodies that bind the motor endplate.
E. An inability to make acetylcholine.