Tag: biology

Under the normal conditions heart rate has an inverse relation with the size of the animal.

The vagus nerve is part of the parasympathetic nervous system, which slows the heart rate by releasing acetylcholine at the SA node.

A neurogenic heart is one where the heartbeat is initiated by nerve impulses from a ganglion, which is characteristic of many lower invertebrates. Humans have a myogenic heart, where the impulse originates in the heart muscle itself.

The pulmonary artery carries deoxygenated (impure) blood from the right ventricle of the heart to the lungs for oxygenation.

The pulmonary artery receives deoxygenated blood pumped out by the right ventricle to transport it to the lungs.

Pulmonary veins carry oxygenated blood from the lungs back to the left atrium of the heart. This is the exception to the rule that veins carry deoxygenated blood.

The Bundle of His (AV bundle) conducts the electrical impulse from the AV node to the Purkinje fibers, which then distribute the impulse to the ventricular muscle.

Oxygenated blood returns from the lungs to the left atrium of the heart via the pulmonary veins.