Overview of Human Anatomy: The Anatomy of Human Systems Image

Human anatomy is the study of the morphology, or physical composition, of the human body. It’s often paired with the study of physiology, or how the systems work and interact with one another.

The human body is made up of a number of systems. Each system is highly organized, with cells making up tissues. These tissues make up organs, which comprise the systems of the human body. Anatomy and physiology are fields that work to explain and understand the specific structure and function of each of these systems. Studying the anatomy of human organs and systems can help us learn more about what ages us, what makes us sick and what can keep us healthy.

The Circulatory System

The function of the circulatory system is to keep a continual flow of blood running through the body. Blood supplies oxygen and nutrients to the tissues of the body and carries harmful metabolic wastes away.

The heart, which consists of four chambers, is the main organ of the circulatory system. The right ventricle and right atrium pump deoxygenated blood from the body through the lungs. Then, the left ventricle and left atrium push blood through the aorta to the entire body.

Arteries and capillaries carry oxygenated blood to all the cells of the human body. The vena cava system of veins then carries deoxygenated blood back to the heart.

The Respiratory System

The function of the respiratory system is to supply the body with oxygen and relieve it of carbon dioxide. The organs that define the respiratory system are the lungs. The respiratory system also consists of the:

  • Larynx
  • Lungs
  • Nasal cavity
  • Pharynx
  • Trachea.

Find out about the respiratory system, including lung anatomy and anatomy of the nose.

The Digestive System

The digestive system breaks down food so it can be used by the body or eliminated. The organs that make up this system include the large and small intestines, the liver and the stomach.

The mouth, esophagus and rectum play important roles in delivering food through the system. The digestive system uses both mechanical and chemical resources: for example, the pancreas and gallbladder produce enzymes to help break down substances.

Learn more about the digestive system, including intestine anatomy.

The Excretory System

In the human body, the excretory system excretes nitrogenous wastes and regulates water levels in the body. The main organs involved in the excretory system are the kidneys. They filter all the fluids in the body, and excrete metabolites and minerals as urine.

Discover interesting facts about the human urinary tract system.

The Nervous System

The function of the nervous system in the human body is to help an individual survive by coordinating information from the external world.

The central nervous system (CNS) is made up of the brain and spinal cord.The peripheral nervous system (PNS) is made up of the sensory and motor neurons that are outside of the CNS.

Learn more about the nervous system, including brain anatomy.

The Musculoskeletal System

The musculoskeletal system gives the human body the ability to move by supplying structural support. The skeleton is made up of cartilage and bone. Ligaments connect bone to bone, and cartilage protects them when they rub together. Three types of muscle — skeletal, cardiac and smooth — are responsible for the movement of the human body.

The Reproductive System

The function of the reproductive system is, tellingly, to allow humans to reproduce. This system is comprised of the sex organs, which are different in the male and female human body.

The female sex organs include the fallopian tubes, mammary glands, ovaries, uterus and vagina.The male sex organs include the penis, prostate, seminal vesicles, testes and vas deferens.

Learn about male anatomy and female anatomy, including breast anatomy.

The Endocrine System

The endocrine system is responsible for creating chemical messengers, such as hormones. These messengers travel through the bloodstream to affect specific target cells. The endocrine glands include the hypothalamus and the pituitary glands, which are both found in the brain. Hormones secreted by these glands control other glands, including the thyroid and parathyroid glands, which affect metabolism.

The Immune System

The function of the immune system is to protect the body from foreign invaders, like bacteria and viruses. The parts of the body involved in the immune response include the:

  • Adenoids
  • Leukocytes
  • Spleen
  • Tonsils
  • Thymus.

The Integumentary System

As part of the human integumentary system, the skin — the body’s largest organ — aims to protect the body against dangerous pathogens and water loss. The skin is also instrumental in protecting deeper levels of the human body. Human skin has three main layers: the epidermis, the dermis and the hypodermis.

Learn about skin anatomy, freckles and moles, how to take care of facial skin, what denotes healthy skin and the role of skin pigmentation.


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Inner Body. (n.d.) Inner Body: Your guide to human anatomy online. Retrieved January 13, 2010, from

Weiss, T. (2009). The human immune system. Retrieved January 13, 2010, from