24.21: Overview of Systemic Arteries
The human body is a complex, well-organized machine, and at the heart of its operations lies the circulatory system. This network of blood vessels, which includes systemic arteries, plays a vital role in maintaining life by transporting nutrients, oxygen, and waste products to and from cells throughout the body.
Systemic circulation is the part of the cardiovascular system that carries oxygenated blood away from the heart to the body's tissues and returns deoxygenated blood back to the heart. It involves all the blood vessels in the body, including the systemic arteries, arterioles, capillaries, venules, and veins, except for those involved in pulmonary circulation.
Coronary circulation refers to the flow of blood through the arteries and veins that supply the heart muscles. The coronary arteries, branching off from the aorta, carry oxygen-rich blood to the myocardium (heart muscle). The coronary sinus, a large vein on the heart's posterior side, collects deoxygenated blood from the heart muscle and channels it into the right atrium. This process is crucial, as it ensures the heart receives the oxygen and nutrients it needs to function effectively.
Cerebral circulation involves the movement of blood through the brain's network of blood vessels. The brain requires a consistent supply of oxygen and nutrients, delivered via the cerebral arteries, to function correctly. Disruptions to this flow can lead to severe neurological conditions such as stroke.
Hepatic circulation involves the flow of blood to and from the liver. This process is essential for maintaining metabolic balance within the body. The liver receives nutrient-rich blood from the digestive organs via the hepatic portal vein and oxygenated blood from the hepatic artery. Deoxygenated blood is then carried away from the liver to the heart by the hepatic veins.
Pulmonary circulation differs from other subdivisions in that it involves the transport of deoxygenated blood from the heart to the lungs and then back to the heart. In this circulation, the deoxygenated blood is transported by the pulmonary arteries from the right ventricle of the heart to the lungs, and the oxygenated blood flows through the pulmonary veins from the lungs, emptying into the left atrium of the heart. This contrasts with systemic circulation, where arteries typically carry oxygenated blood away from the heart and veins carry deoxygenated blood back to the heart. This process is vital for oxygenating the blood and removing carbon dioxide.
The superior and inferior venae cavae are the primary veins that transport deoxygenated blood from the body back to the heart. The superior vena cava brings blood from the upper part of the body, whereas the inferior vena cava transports blood from the lower part. Both of these veins drain into the right atrium of the heart, from where the blood is pumped to the lungs for oxygenation.
