Circulatory system

by. jessica lee

overall functions

There are few functions that the circulatory system has in its system. They contain cells that fight infection, helps stabilize the pH and ionic concentration of the body fluids and it helps maintain body temperature by transporting heat. The system also transport lots of materials through the body. Oxygen is transported from the lungs to the cells and CO2 is transported from the cells to the lungs. Nutrients are transported to the cells and numerous hormones that help maintain constant internal conditions are transported. Without the circulatory system, our body would not be able to fight disease or maintain homeostasis.

Organs and individual roles

The heart, lung, blood, and blood vessels: arteries, veins, capillaries are main organs that make up the circulatory system. Heart is a muscular organ with four chambers. It pumps blood through the networks of arteries and veins. Even though the lungs are part of the respiratory system, it takes part in circulatory system by delivering oxygen to the blood so that it can be pumped through the arteries by the heart and delivered to the rest of the body. The arteries are the vessels that carry nutrient and oxygen-rich blood away from the heart and deliver it to all of the parts of the body. The thickest artery is the largest blood vessel in the entire body, the aorta. The veins receive blood from the capillaries after the capillaries have delivered all of the oxygen and nutrients to the body parts and removed the waste. Capillaries are able to exchange food, oxygen, and wastes between blood cells and body cells through gas exchange and diffusion.

Specialized cells

The nervous tissue's main function is to react to stimuli and send impulses to various organs around the body. Epithelium is a type of protective tissue that covers the entire body and the heart. It is made up of closely packed cells in one or more layers. Epithelial tissue found inside the body is called endothelium where it usually sits on top of a thin layer of connective tissue called the basement membrane. In the circulatory system, epithelial tissue can be found in the structure of the arteries, veins, and capillaries. Muscle tissue is made up of muscle cells which are able to contract, whether it is involuntarily or on demand. This is the tissue that enables us to move our whole body, or just certain parts. Muscle tissue also creates involuntary movement inside our bodies in every organ system. Nervous tissue is made up of special cells called neurons. They are highly responsive which means that they react quickly to stimuli. The nervous tissue helps the brain to transmit messages to all of the components of the circulatory system. Without this tissue, the circulatory system would not function. Connective tissue holds the body together and it is the most common and plentiful type of tissue in the entire body. The connective tissue consists of widely spread cells and its job is to connect, support, or surround other tissues and organs. The connective tissue is what makes up the structure of not only the circulatory system, but all of the other organ systems as well. This tissue can be found in the walls of arteries, veins, and capillaries, and in the makeup of the heart.

Red blood cells make up about 45% of the blood. The most important job of the red blood cells is to transport oxygen and other nutrients to all of the parts of the body and to get rid of wastes in the body, such as carbon dioxide. Platelets are small blood cell fragments that help mend wounds by causing blood to clot. When a tissue is cut and bleeding, platelets build up over the wound and work with proteins nearby to form a web which eventually hardens to create a scab, preventing any more blood loss. 53% of the blood in our body is plasma, which is a yellowy coloured substance that gives the blood a liquid consistency. This liquid is mostly water but also contains dissolved sugars and calcium.


Circulatory and muscular systems work together to provide the movement of blood throughout the body.