The Cardiovascular system
The Cardiovascular system, also called the circulatory system, comprises:
The cardiovascular system delivers oxygen, nutrients, hormones, and other important substances to cells and organs in the body, and removes waste or spent substances from them.It is one of the two major transport systems of the body, the other being the lymphatic system.
A properly functioning cardiovascular system is essential for homeostasis , that is a fairly constant state of temperature, ions and other other operating conditions within the body and it also ensures that the body is well able to deal with the demands of activity, exercise, and general or specific threats and stress.
The heart's main job is to pump oxygen-rich blood to the body. It normally does this 60 - 100 times a minute, 24 hours a day.
The heart is made of four chambers:
Arteries carry blood away from the heart and veins carry blood back to the heart. Arteries and veins have three layers, but the middle layer, that is, the layer of muscle, is thicker in the arteries than it is in the veins. The contraction and relaxation of this layer of muscle surrounding arteries and veins assists in regulating pressure within the vessels and allow for blood to be pumped around the body.
Capillaries consist of little more than a layer of epithelial tissue and occasional connective tissue.
When the ordered circulatory systems is blocked or damaged, the body must find a way to deliver critical nutrients and other supplies to affect organs and tissues. In such cases, a number of blood vessels may connect to form a region of diffuse vascular supply, called an anastomosis, that provide critical alternative routes for blood to flow.
For further reading and research into the causes, nature and risk factors of Hypertension, you may visit the links below, among others.