Human Circulatory System

Red blood cells (erythrocytes) are produced in the bone marrow through a process called erythropoiesis. In adults, this primarily occurs in the vertebrae, sternum, ribs, and pelvis. The liver produces RBCs only during fetal development.

A biopsy is a medical procedure where tissue samples are taken from a living body (in vivo) for microscopic examination to diagnose diseases like cancer. Post-mortem tissue analysis is called an autopsy, not a biopsy.

The pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation - this is why it's called 'impure blood.' The pulmonary vein does the opposite, carrying oxygenated blood back to the heart.

Plasma is the yellowish liquid component of blood that makes up about 55% of blood volume. It consists primarily of water, proteins, and dissolved substances like nutrients and waste products.

Coronary arteries are the blood vessels that supply oxygenated blood to the heart muscle itself. The term 'coronary' comes from the Latin word for 'crown' because these arteries encircle the heart like a crown. Carotid arteries supply the brain, hepatic arteries supply the liver, and pulmonary arteries carry deoxygenated blood to the lungs.

The heart is the muscular organ that pumps blood throughout the body via the circulatory system. It continuously pumps oxygenated blood to all tissues and returns deoxygenated blood to the lungs.

While the heart creates significant pressure (systolic pressure around 120 mmHg), it cannot squirt blood 45 feet. This is an exaggeration. Blood pressure is sufficient to circulate blood throughout the body but not for such extreme distance projection.

The spleen is called the 'blood bank' of the human body because it stores red blood cells and platelets, releasing them during emergencies like hemorrhage or shock. The spleen also filters old or damaged blood cells and plays a role in immune function.

The pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs. It is the only artery that carries deoxygenated blood - all others carry oxygenated blood.

The total length of blood vessels in an average adult human body is approximately 160,000 km. This includes arteries, veins, and capillaries, with capillaries making up the vast majority of this length.