Question

Systemic heart refers to
A. The heart that contracts under stimulation from nervous system
B. Left auricle and left ventricle in higher vertebrates
C. Entire heart in lower vertebrates
D. The two ventricles together in humans

Answer 1

The Heart is a muscular organ about the size of a fist. The heart pumps blood and nutrients to the whole body by the blood vessels (arteries and veins). Heart helps the body to maintain the constant body temperature (thermoregulation). It is derived from the mesoderm.

Complete answer:
Systemic heart refers to the left auricle and left ventricle in higher vertebrates. The left side of the heart which is involved in the systemic circulation known as systemic heart.
There are two types of circulation:
Pulmonary circulation: The deoxygenated blood pumped into the pulmonary artery is transferred to the lungs from where the oxygenated blood is carried by the pulmonary veins into the left atrium. This pathway is known as pulmonary circulation.
Systemic circulation: The oxygenated blood entering the aorta is carried by a network of arteries, arterioles and capillaries to the tissues from where a system of venules, veins and vena cava collects the deoxygenated blood and empty into the right atrium. This circulation provides nutrients, oxygen and other essential substances to the tissues and removes carbon dioxide and other harmful substances.

So the correct answer is option B.

Note: Systemic circulation provides greater resistance to blood flow than that in the pulmonary circulation because it has numerous small muscular arteries and arterioles. Left ventricle is thicker than the right ventricle because work done by the left ventricle is much more than the right one.