Question

1. What contracts the Heart?

2. Immunity results from recovery after Strep throat is a example of what?

Answer 1

1. The sinoatrial node or the SA node in the right atrium of the heart generates an electrical impulse which spreads through the walls of the atria and causes it to contract and sets the sinus rhythm, the atrioventricular node slows down the rate of spread of the electrical impulse before it reaches the ventricles, during which time the atria has contracted. Once the electrical impulses reach the ventricles, the His-Purkinje network a pathway of fibres relay the electrical impulse to the muscular walls of the ventricles and causes them to contract resulting in pumping out of the blood from the heart to the rest of the body.

2.The immunity which results after a strep throat recovery is an example of adaptive immunity or in plain terms acquired immunity facilitated by the B and T lymphocytes.