Human Body Systems: Anatomy, Organs & Functions

Anne Kamiya, Betsy Chesnutt
  • Author
    Anne Kamiya

    Anne has experience in science research and writing. She has a graduate degree in nutrition (focus on nutritional microbiology) and undergraduate degrees in microbiology (immunology and medical microbiology) and English (myth and folklore). She has also worked as an ocean & Earth science educator.

  • Instructor
    Betsy Chesnutt

    Betsy has a Ph.D. in biomedical engineering from the University of Memphis, M.S. from the University of Virginia, and B.S. from Mississippi State University. She has over 10 years of experience developing STEM curriculum and teaching physics, engineering, and biology.

Learn about the human body's anatomy and the major body systems. Study the body systems, as well as the many organs in the body and their specific functions. Updated: 04/10/2022

Table of Contents


Understanding the Anatomy of the Human Body

Human body systems are comprised of many parts, from the smallest cells to the most robust bones. What makes the body amazing is how these parts come together to function as a whole. The smallest units in the body are cellular, and cells cluster to create tissues. When tissues coalesce, they create organs. Although organs in the body may seem separate, they all cooperate. A good example of cooperating organs are the stomach and intestines, which digest food. When sets of organs work together, they are called an organ system or body system.

Major external human body parts include the head, neck, shoulders, trunk (thorax, abdomen, pelvis, and back), and the upper and lower limbs. Internal structures include arteries, veins, bones, joints, connective tissue, epithelial tissue, muscles, nerves, organs, and adipose tissue.

An illustrated diagram of the human body, with an X-ray view showing multiple organs, structures, and organ systems.

Human body systems diagram depicting different organs and organ systems.

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: What is DNA?

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:04 Cardiovascular & Endocrine
  • 1:21 Integumentary &…
  • 2:17 Lymphatic & Nervous
  • 3:30 Digestive & Urinary
  • 4:48 Respiratory & Reproductive
  • 6:05 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

The Ten Human Body Systems

  • Musculoskeletal system. Acts as the supportive framework for the body, giving the body strength, movement, structure, and form.
  • Cardiovascular system. Circulates blood throughout the body so oxygen and nutrients can be transported to cells, tissues, and organs.
  • Respiratory system. Takes in oxygen from the external environment and expels carbon dioxide waste, enabling cellular breathing, or respiration.
  • Lymphatic system. This human body system is also called the immune system. It creates cells that combat infections and maintains tissue integrity by cleaning up cellular debris.
  • Nervous system. Comprised of a network of cells that transport electrical signals, called neurons, that runs throughout the body. The nervous system enables senses, movement, and response to environmental stimuli.
  • Endocrine system. Sometimes called the neuroendocrine system, this body system uses hormones to direct reproduction, growth, development, and metabolism.
  • Integumentary system. Also known as the skin, this body system primarily provides external protection to all other organ systems, tissues, and structures within the body.
  • Digestive system. Provides nourishment to the body by breaking down large chunks of food into microscopic particles that can be absorbed into the circulatory and lymphatic systems. Multiple organs in the body comprise the digestive system.
  • Urinary system. This body system primarily expels fluids and mineral wastes.
  • Reproductive system. The structures of these human body systems vary based on sex. The reproductive system produces and maintains sex cells called gametes for sexual reproduction.


The musculoskeletal system is comprised of the following human body parts: bones, joints, ligaments, tendons, cartilage, and muscle. Musculoskeletal tissue spans the entire body. Its function is to give the body strength, an internal support structure, and the ability to move and interact with the environment. Sometimes the musculoskeletal system is separated into two human body systems: the muscular system and the skeletal system. Many organs in the body work with and rely on the musculoskeletal system. For instance, the nervous system receives and sends signals to direct muscle movements, and the digestive system is a series of long, muscular tubes.


The heart is the major organ of the cardiovascular system and pumps blood through arteries and veins. The heart is in the thorax, while veins and arteries span the entire body. All human body systems, human body parts, and organs in the body are dependent on the cardiovascular system. The respiratory system supplies the heart with freshly oxygenated red blood cells. The digestive system provides the blood with nutrients. Hormones from the endocrine system are transported through the blood. Waste products are also transported through the blood to the urinary system. The lymphatic system, too, relies on the transport of immune cells through the cardiovascular system. And every tissue, cell, and organ in the body needs a constant supply of oxygen from oxygenated blood to survive.


The respiratory system includes the lungs and other human body parts needed for breathing, including the nose, pharynx, larynx, trachea, and bronchi. This body system is located in the thorax, neck, and head. The respiratory system, along with the cardiovascular system, are human body systems vital for life.

The lungs are filled with tiny clusters of balloon-like structures called alveoli, which trap both oxygen and carbon dioxide. When humans breathe air, they inhale oxygen, which is collected by the alveoli and given to red blood cells. When the oxygen is used up, red blood cells bring back carbon dioxide waste. The alveoli feed oxygen into the blood and expel carbon dioxide through breathing out.


Also called the immune system, the lymphatic system is the guardian of the body, warding off infections and cleaning up old, dead cells. The lymphatic system spans the entire body as a network of vessels that link to clusters of lymph nodes, which are hubs for immune cells. It also includes additional human body parts, including the bone marrow, spleen, and thymus, which help store, grow, and develop immune cells. The skin is also considered a part of the immune system because it acts as a barrier to prevent bacteria and other harmful organisms from entering the body. All human body systems and organs in the body rely on the lymphatic system for protection.


The nervous system is a sensory and control system for the entire body and is vital for all human body systems and organs in the body to function. It includes the brain, the spinal cord, and neurons. The brain is the primary control hub and is part of the central nervous system (CNS). The spinal cord acts as a highway for electrical signals to travel back and forth between the brain and body, and is also part of the CNS.

Neurons span the entire body, from the head to the feet. The neuron network picks up environmental information and sends it to the brain. The brain also transmits signals via neurons to every organ, muscle, and tissue in the body to tell it how to function and what to do. Much of the brain is also made from neurons. Neurons extend outwards from the spine and supply other human body parts with sensory nerve tissue, like the skin and muscles. These sensory neurons are part of the peripheral nervous system (PNS). The reason why human beings can feel, taste, smell, see, hear, and have a sense of balance and awareness of their own bodies is because of the nervous system.


The function of the endocrine system is to direct and control metabolism, growth, and sexual reproduction. This body system works closely with other human body systems, particularly the nervous system and the reproductive system. Although the endocrine system involves only a specific set of organs in the body, glands in endocrine organs produce hormones that circulate in the blood and affect all cells, tissues, and human body parts.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it now
Create an account to start this course today
Used by over 30 million students worldwide
Create an account