Circulatory system

Definition

The circulatory system is a network of organs and vessels responsible for the flow of blood, nutrients, hormones, oxygen, and other gases to and from cells. It includes the heart, blood, and blood vessels.

5 Must Know Facts For Your Next Test

1. The circulatory system consists of two primary components: the cardiovascular system and the lymphatic system.
2. The heart pumps oxygenated blood through arteries to tissues and returns deoxygenated blood through veins back to the heart.
3. Blood is composed of red blood cells, white blood cells, platelets, and plasma; each component has a specific function in circulation and immune response.
4. Capillaries are the smallest blood vessels where gas exchange occurs between blood and tissues.
5. Infections such as bacteremia (bacteria in the bloodstream) can spread rapidly through the circulatory system causing systemic infections.

Review Questions

• What are the main components of the circulatory system?
• How do arteries differ from veins in terms of their function within the circulatory system?
• What role do capillaries play in the circulatory system?

Related terms

Cardiovascular System:

A subsystem of the circulatory system that includes the heart and all blood vessels.

Lymphatic System:

A network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials.

Bacteremia:

The presence of bacteria in the bloodstream which can lead to systemic infections.