Cardiomyocytes Multiple Choice Questions PDF

## Cardiomyocytes 1. What is the stable resting potential of cardiomyocytes? * -90 mV * +30 mV * -70 mV * 0 mV 2. The threshold voltage rapidly opens additional Na+ channels and triggers a positive feedback cycle like the one seen in the firing of a neuron. The action potential peaks at?...

## Cardiomyocytes 1. What is the stable resting potential of cardiomyocytes? * -90 mV * +30 mV * -70 mV * 0 mV 2. The threshold voltage rapidly opens additional Na+ channels and triggers a positive feedback cycle like the one seen in the firing of a neuron. The action potential peaks at? * -30 mV * 0 mV * +30 mV * +90 mV 3. What percentage of the Ca2+ needed for myocardial contraction is provided by the sarcoplasmic reticulum (SR)? * 10-20% * 30-50% * 70-80% * 90-98% 4. Which type of nerve stimulation can increase the heart rate to as high as 230 bpm? * Sympathetic stimulation * Parasympathetic stimulation * Both a and b * Neither a nor b 5. Which of the following Postganglionic fibers arise in the cervical ganglia, pass through in the mediastinum? * Cardiac plexus * Cardiac nerves * Both a and b * None of the above 6. What is cardiac plexus in the mediastinum, and continue by way? * Cardiac plexus * Cardiac nerves * Both a and b * None of the above 7. The cardiac plexus consists of? * Sympathetic * Parasympathetic * Both a and b * None of the above 8. Which of the following The network of nerves supplying the heart is called? * The cardiac plexus * The cardiac muscle * Both a and b * None of the above 9. The heart is innervated by? * Sympathetic fibres only * Parasympathetic fibres only * Sympathetic and parasympathetic fibres * Somatic nervous system 10. Which of the following are responsible for influencing the heart rate, cardiac output, and contraction forces of the heart? * Sympathetic and parasympathetic fibres * Vague nerves * Cardiac plexus * All of the above 11. The cardiac plexus is a network of? * Arteries * Veins * Nerves * Lymphatic vessels 12. The cardiac plexus includes both the? * Sympathetic and parasympathetic systems * Sensory and motor systems * Somatic and visceral systems * Afferent and efferent systems 13. Which of the Parasympathetic innervation is responsible for? * reducing the heart rate * reducing the force of contraction of the heart * vasoconstriction (narrowing) of the coronary arteries * all of the above 14. Which of the following function vagus nerve? * Sensory and Special Sensory * Motor and Parasympathetic * both a and b * none of the above 15. Which of the following Other vagus nerve effects include? * Communication between the brain and the gut * Relaxation with deep breathing * Decreasing inflammation * all of the above 16. Which of the following Other vagus nerve effects include? * Lowering the heart rate and blood pressure * Fear management * both a and b * none of the above 17. Which of the following Sympathetic nerves are responsible for? * increasing heart rate * increasing the force of contraction of the myocardium * the 'fight or flight' response, causing our heart to beat faster * all of the above