Learn About All the Different Organ Systems in the Human Body

Quiz Yourself on 10 Major Organ Systems

Illustrations of the human body systems
Dorling Kindersley: Owen Gildersleeve / Getty Images

The human body is made up of several organ systems that work together as one unit. In the pyramid of life that organizes all of the elements of life into categories, organ systems are nested between an organism and its organs. Organ systems are the groups of organs that are within an organism.

Ten major organ systems of the human body are listed below along with the major organs or structures that are associated with each system. Each system depends on the others, either directly or indirectly, to keep the body functioning normally.

Once you a feeling confident in your knowledge of the organ system, try a simple quiz to test yourself.

Circulatory System

Digital illustration of the human cardiovascular system (female)
Dorling Kindersley / Getty Images

The main function of the circulatory system is to transport nutrients and gasses to cells and tissues throughout the body. This is accomplished by the circulation of blood. Two components of this system are the cardiovascular and lymphatic systems.

The cardiovascular system is comprised of the heartblood, and blood vessels. The beating of the heart drives the cardiac cycle which pumps blood throughout the body.

The lymphatic system is a vascular network of tubules and ducts that collect, filter and return lymph to blood circulation. As a component of the immune system, the lymphatic system produces and circulates immune cells called lymphocytes. The lymphatic organs include the lymph vessels, lymph nodes, thymus, spleen, and tonsils.

Digestive System

Digital illustration of the human digestive system
comotion_design / Getty Images

The digestive system breaks down food polymers into smaller molecules to provide energy for the body. Digestive juices and enzymes are secreted to break down the carbohydrates, fat, and protein in food. The primary organs are the mouth, stomach, intestines, and rectum. Other accessory structures include the teeth, tongue, liver, and pancreas.

Endocrine System

3D illustration of the female hormone/endocrine system
CHRISTIAN DARKIN / SCIENCE PHOTO LIBRARY / Getty Images

The endocrine system regulates vital processes in the body including growth, homeostasis, metabolism, and sexual development. Endocrine organs secrete hormones to regulate body processes. Major endocrine structures include the pituitary gland, pineal gland, thymus, ovaries, testes, and thyroid gland.

Integumentary System

The integumentary system protects the internal structures of the body from damage, prevents dehydration, stores fat, and produces vitamins and hormones. The structures that support the integumentary system include skin, nails, hair, and sweat glands.

Muscular System

Digital illustration of the human muscles and tendons.
Oliver Burston / Getty Images

The muscular system enables movement through the contraction of muscles. Humans have three types of muscles: heart muscle, smooth muscle, and skeletal muscles. Skeletal muscle is made up of thousands of cylindrical muscle fibers. The fibers are bound together by connective tissue that is made up of blood vessels and nerves.

Nervous System

3D illustration of the human nervous system
Science Picture Co / Getty Images

The nervous system monitors and coordinates internal organ function and responds to changes in the external environment. The major structures of the nervous system include the brainspinal cord, and nerves.

Reproductive System

Illustration showing cross section of male and female reproductive system organs
DEA PICTURE LIBRARY / Getty Images

The reproductive system enables the production of offspring through sexual reproduction between a male and female. The system is comprised of male and female reproductive organs and structures which produce sex cells and ensure the growth and development of offspring. The major male structures include the testes, scrotum, penis, vas deferens, and prostate. The major female structures include the ovaries, uterus, vagina, and mammary glands.

Respiratory System

Digital illustration of the human respiratory system.
LEONELLO CALVETTI / Getty Images

The respiratory system provides the body with oxygen via a gas exchange between air from the outside environment and gases in the blood. The major respiratory structures include the lungs, nose, trachea, and bronchi.

Skeletal System

3D illustration of the human male skeleton.
SCIEPRO / Getty Images

The skeletal system supports and protects the body while giving it shape and form. The major structures include 206 bones, joints, ligaments, tendons, and cartilage. This system works closely with the muscular system to enable movement.

Urinary Excretory System

Three dimensional view of female urinary system, close-up.
Stocktrek Images / Getty Images

The urinary excretory System removes wastes and maintains water balance in the body. Other aspects of its function include regulating electrolytes in body fluids and maintaining normal pH of the blood. The major structures of the urinary excretory system include the kidneys, urinary bladder, urethra, and ureters.