The azygos venous system returns blood from the posterior walls of the thorax and the abdomen and dumps into the superior vena cava. The superior vena cava then takes the blood to the right auricle.

Pericardial fluid keeps the heart moist and protects it from external shocks and friction at the time of bleeding.

Fossa ovalis is an oval depression in intra-auricular septum, which is a vestige of an oval aperture. #

The right auricle receives deoxygenated blood from superior and inferior vena cava.

The heart is enclosed in a transparent membranous bag called pericardium.

Papillary muscles that are situated in the left ventricle prevent the mitral valve from being pushed into the auricles at the time of ventricular contraction.

This is the right course. RA receives deoxygenated from body. Deoxygenated blood then passes to RV from where it goes to the lungs for oxygenation. The oxygenated blood comes to LA from the lungs, from where it goes to LV to be supplied to the whole body.

A normal heart rate falls in the range of 60 to 100 beats per minute.

This is a myth. In actuality, the heart is located in the middle of your chest and sits between lungs. The bottommost part of the heart is slightly tipped to the left but the heart is really in the center of your chest.

The left auricle receives oxygenated blood from the lungs by  the four pulmonary veins.

Between the parietal and visceral layers of serous pericardium, a narrow space is present which is called the pericardial cavity.

The mitral valve guards the opening between the left atrium and the left ventricle.

The aorta artery supplies blood to the whole body.

It is the middle layer of the cardiac wall and is formed of cardiac muscle fibres.

Semilunar valves prevent the backflow of blood from the arteries to the ventricles.