Defination
he circulatory system, also known as the cardiovascular system, consists of the organs and fluids that transport materials across the body. All vertebrates, including humans, have a closed circulatory system, which means that blood remains within blood vessels and does not directly interact with body tissues.
Circulatory System Parts. The circulatory system consists of the heart, blood, blood vessels, lymph, and lymphatic vessels. While the heart is the only “organ” of the circulatory system, it is really only a vessel surrounded by muscles. The circulatory system does not have standard organs. circulatory system consists of three independent systems that work together: the heart (cardiovascular), lungs (pulmonary), and arteries, veins, coronary and portal vessels (systemic). The system is responsible for the flow of blood, nutrients, oxygen and other gases, and as well as hormones to and from cells.
An average adult has 5 to 6 quarts (4.7 to 5.6 liters) of blood, which is made up of plasma, red blood cells, white blood cells and platelets.The heart is a muscular organ with four chambers. Located just behind and slightly left of the breastbone, it pumps blood through the network of arteries and veins called the cardiovas- cular system.
The systemic circulation is a major portion of the circulatory system. The network of veins, arteries and blood vessels transports oxygenated blood from the heart, delivers oxygen and nutrients to the body's cells and then returns deoxygenated blood back to the heart.
The system of blood vessels in the human body measure about 60,000 miles (96,560 kilometers).
Arteries carry oxygen-rich blood from the heart through the body. Veins carry oxygen-poor blood back to the heart.
The superior vena cava carries oxygen-poor blood into the heart. The aorta carries oxygenated blood from the heart to organs and tissues.
Circulatory System Function
Animal evolution has resulted in an increasing degree of specialization within tissues and organs. For instance, simple multicellular organisms like sponges have structures where every cell interacts directly with the environment. Each cell exchanges materials, obtains nutrients, and expels its waste into the extracellular region. In larger, more complex animals, however, this is difficult since there are many cells present deep inside the organism that interact minimally with the external environment.
Example of Circulatory System Function
For instance, the intricate network of blood vessels that surrounds the small intestineabsorbsthe end products of digestion. The pituitary gland situated deep within the brain releases hormones that influence the musculoskeletal, integumentary, and reproductive systems.These hormones are carried to their target organs and cells through the circulatory system. At alveoli, oxygen from the air diffuses into capillaries where it binds to hemoglobin in red blood cells. Through this carrier protein, blood delivers oxygen to every cell within the body.
Circulatory System Structure
As a whole, the circulatory system has a general pattern, structure, and flow. Blood starts in the heart, where it is split into two patterns of circulation. The pulmonary circulation goes to the lungs and back to the heart. This circuit is used to oxygenate the lungs. Then, the blood reenters the heart and is pumped through the systemic circulation.
These veins and arteries serve the body and have a standardized setup. First, arteries carry oxygenated blood toward the tissues. As the arteries get closer to their target tissue they get smaller and smaller, eventually leading to capillaries. Capillaries are the smallest of all vessels, and they serve as the site of gas exchange in the tissues. On the other side of capillaries, the veins start. Veins carry deoxygenated blood, along with various waste products, back towards the heart. The waste products will be excreted in the lungs, or they are filtered out by the liver or kidneys.