William Harvey and the Discovery of the Circulation of the Blood

Drug discovery is a multifaceted process involving extensive screening, testing, and optimization of lead compounds to identify potential new drugs for therapeutic use. It combines several approaches, including screening large numbers of natural products, chemical modification of known active molecules, identification of new drug targets, and rational design based on biological mechanisms and drug-receptor structure. These approaches are carried out in both academic research laboratories and...

Fetal circulation is a unique system that facilitates the exchange of gases, nutrients, and waste products between the developing fetus and the mother. This intricate process takes place through a special organ called the placenta.
Two umbilical arteries transport blood from the fetus to the placenta. At the placenta, the blood absorbs oxygen and nutrients while simultaneously eliminating waste products. This oxygen-enriched and nutrient-rich blood then returns to the fetus through one...

The heart, an organ critical to survival, gets nourishment not from the blood it pumps but from a separate circulation system known as coronary circulation. This is the shortest circulation in the body and is responsible for supplying the heart with the nutrients it needs to function effectively.
Coronary circulation begins at the base of the aorta, where two main arteries arise—the left and right coronary arteries. These arteries encircle the heart in the coronary sulcus and supply the...

The pulmonary circulation is a vital system in our body that acts as a bridge between the respiratory and cardiovascular systems. It serves as a transport network for deoxygenated blood from the heart to the lungs and then returns oxygen-rich blood back to the heart.
The process begins with the right ventricle of the heart pumping deoxygenated blood into the pulmonary trunk. This large vessel extends about 5 centimeters before splitting into the left and right pulmonary arteries. These arteries...

The systemic and pulmonary circuits are crucial components of the circulatory system, working together to transport blood between the heart, lungs, and the rest of the body. The process begins with pulmonary circulation, where deoxygenated blood is pumped from the right ventricle to the lungs via the pulmonary trunk and arteries. Upon reaching the lungs, the blood becomes oxygenated and returns to the heart, specifically to the left atrium, via the pulmonary veins.
The oxygenated blood is sent...

Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The velocity of blood flow decreases with increased cross-sectional blood vessel area. As blood returns to the heart through venules and veins, its velocity increases. The movement of blood is encouraged by smooth muscle in the vessel walls, the movement of skeletal muscle surrounding the vessels, and one-way valves that prevent backflow.