Functions and Types of Circulatory System

The body is made of cells. Cells need nutrients and oxygen to survive, and wastes need to be removed from them. Hormones are also needed to be transported from the endocrine glands which secrete them to their respective target cells. This work of transportation of nutrients, gases, wastes and other substances from one part of our body to the other part, is carried out by blood, and termed circulation.

The organs responsible for the flow of blood and lymph through various parts of the body constitute the circulatory system.

Functions of Circulatory System

1. Transport of nutrients to the tissues for their utilization.
2. Transport of respiratory gases (O₂ and CO₂) to and from the cells.
3. Collection of metabolic wastes from different tissues and transporting them to excretory organs for their removal.
4. Transport of hormones from endocrine glands to target organs.
5. Protection of body by destroying pathogens.
6. Uniform distribution of heat in the body.

Types of Circulatory System

Depending upon the mode of circulation, the circulatory system may be open or closed type.

Open Circulatory System

Blood does not flow in closed vessels rather it flows through parts of the body cavity. It remains mixed with the body fluid. Sufficient high pressure for circulation is not maintained. Organisms like prawns, and insects have open circulatory system.

Closed Circulatory System

Blood flows in well-defined tube-like vessels. Sufficient high pressure is maintained. System is more efficient than open type. Closed system is found in all vertebrates.