Question

1. Discuss the differences in contractile cardiac muscle and skeletal muscle action potentials. 2. Under what conditions would RHOgam be given to a patient based on what was discussed in lecture? Why? (Meaning what is the activity of the medication, and what is the condition being prevented) 3. You're watching a child for your friend who was called into work. Unfortunately, you've recently had rodents trying to take up residence in your cabinets and have decided to take action. You have not childproofed your house, and the kid finds and eats some of the rat poison. Good job, babysitter! Other than fearing a lengthy prison sentence for yourself, what do you fear will happen to the child? (1 am looking for something more detailed than it will die) When you get the child to the ER, the first thing the doctors do is administer a massive dose of vitamin K. Why do they do this? SER SO ESC 4. You went on a vacation to Africa and picked up a nice case of Dracunculiasis. This thing will live in you for up to a year undetected, mating, and eventually traveling to your foot or calf. There will be excruciating pain that is alleviated only by placing your leg in water. The Guinea worm responsible for all of this detects the water, and ruptures through your foot/leg spilling eggs into the water to infect water fleas that may be in the area, which might eventually find their way into another human, continuing the cycle. If you're the health-conscience type, you might have gone to the doctor sometime in that year of no symptoms and had some bloodwork performed. What might show up on your results that could save you from having that worm burst through your foot?

Answer 1

Action potentials in the cardiac muscle vary considerably from action potentials in neural and skeletal muscle cells. One significant distinction is in the duration of the action potentials. In a normal neuron, the duration of the action potential is about 1 ms. In skeletal muscle cells, the duration of the action potential is about 2-5 ms. On the other hand, the duration of cardiac action potentials extends from 200 to 400 ms.
Another variation between the action potentials of cardiac and skeletal muscle is the purpose of calcium ions in the process of depolarization. In skeletal muscle cells, the depolarization phase of the action potential is produced by the availability of sodium channels. This also happens in non-pacemaker cardiac cells. Although, in cardiac pacemaker cells, calcium ions are required in the initial depolarization phase of the action potential. In non-pacemaker cells, calcium inflow increases the duration of the action potential and produces a characteristic phase.