... period between action potentials greater and the heart rate falls. There is very little parasympathetic negative inotropic innervation to the ventricles, but drugs such as propranolol which act as '-adrenoreceptor antagonists ('-blockers) do reduce the contractility of the myocardium. Sympathetic innervation of the heart serves to speed up the heart and increase the stroke volume. The sympathetic nerves begin in the ... ...

• Word Count: 1504
• Approx Pages: 6
• Grade Level: Undergraduate

... becomes desensitized to any agonist action. This mechanism differs from the action of non depolarising blockers greatly. They have their effect by competing with acetylcholine for receptor sites. They are antagonists, so they have no effect on the receptor other that to deprive the active site to an agonist. The experiment is to see if there is a difference in the results ... ...

• Word Count: 1088
• Approx Pages: 4
• Grade Level: Undergraduate