Human Body

Body Systems – Definition and List of Body Systems

Definition of Body Systems

We can define body systems as groups of organs and tissues that work together to perform important jobs for the body. There are some organs in our body which are part of more than one body system as they serve more than one function. Apart from these, other organs and tissues serve only one purpose in the body system. All body systems are necessary for an organism to be able to survive and reproduce. Below, we’ll learn how our organs and tissues work together as body systems to accomplish these tasks. There is a total of 10 major parts of body systems as follows.


body systems



List of Body Systems in Human Body

1. Respiratory System

It executes the gas exchange between cells and the environment and includes trachea and lungs. The respiratory system takes oxygen from the environment and converts it into a form that cells can use. In humans, it means that our lungs take in oxygen, and rapidly diffuse it into the blood.

The lungs accomplish this function by passing large amounts of blood over gas exchange membranes; the body’s whole blood volume passes over these membranes about once per minute. Without oxygen to fuel cellular respiration, cells begin to die within minutes. Thus, the respiratory system is one of the body’s most important system.

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2. Digestive System or Excretory System

This system intakes food, breaks it down into usable nutrients and excretes solid waste products. It includes the mouth, esophagus, stomach, and intestines. One of the most important purposes of food is to serve as cellular fuel. Also, carbohydrates, proteins, and fats can all be used by our cells as sources of the energy that they need to stay alive.

3. Cardiovascular or Circulatory System

This system moves materials between body systems, including oxygen, nutrients, hormones, and waste products. It includes the heart, arteries, and veins. This system takes only about a minute to circulate the whole body’s entire blood volume thus making this a truly high-speed expressway for distributing oxygen, nutrients, messages, and removing waste.

In addition to oxygen and nutrients, this organ system also transports chemical messages, such as hormones, around the body. This allows the adrenal glands, for example, to send messages that cause our whole body to prepare for fight or flight.

4. Renal System or Urinary System

It cleans dissolved waste products from the blood and excretes them. It includes kidneys and bladder. All blood is passed through the kidneys, where special filters allow dangerous substances to pass out of the bloodstream while keeping helpful substances in. The waste liquid that’s filtered out by the kidneys is stored in the bladder until the body expels it.

5. Endocrine System

This system sends secret chemical signals that allow body systems to act cooperatively as require. These secret messages have their own unique purpose, to which the body’s other systems respond accordingly.

It also includes hormone-producing tissues of the pineal gland and pituitary gland in the brain; the thyroid gland; the adrenal glands; the pancreas; and the ovaries and testes. Some examples of messages sent by the endocrine system are Fight or flight, reproductive signals, hungry or full.

6. Nervous System

This system allows perception, emotion, thought, and rapid response to the environment. It includes the brain and nerves. The nervous system allows us to sensory stimuli such as light, sound, smell, and touch from our environment.

It also allows rapid communication of stimuli within our body, such as sensations of pain, illness, and wellness. The nervous system accomplishes all of this using highly specialized cells called neurons, which can transmit signals extremely fast by firing electrochemical potentials.

7. Musculoskeletal System

It allows the body to move on command. The system of muscles throughout an organism operates to move the organism and stimulate the internal organs. There are several main types of muscles in a mammal: smooth muscle, skeletal muscle, and cardiac muscle. The skeletal system of animals consists of either an endoskeleton, like mammals, or an exoskeleton, seen in insects.

With the help of endo and exoskeletons, the muscles attach directly to the skeleton, through tendons and other connective tissues. This formation allows the muscles to pull on the skeleton, creating opposing forces. These forces allow the limbs to move.

8. Integumentary System or Exocrine System 

This system covers the body and regulates its exchange with the outside world. It comprises of skin, hair, nails, sweat, and other glands which secrete substances onto the skin.

9. Lymphatic System or Immune System

This system fights infection and includes lymphatic vessels which permeate the body. Every living thing needs to be able to fight infection. We have white blood cells that can specially target and destroy invading pathogens. These white blood cells are made in our bone marrow and stored in our blood and our lymphatic systems.

10. Reproductive System

This system is related to the production of offspring. It includes ovaries, uterus, mammary glands (breasts), penis, and testes. The reproductive system is not essential to individual survival, but it is essential for the survival of the species.

In humans, there are two very different reproductive systems: the male system, which is concerned primarily with producing sperm and finding mates; and the female system, which must prepare for pregnancy, childbirth, and baby care for reproduction to be successful.

Solved Question for You

Q. Which is largest organ of the body?

Ans- The largest external organ, which is also the largest organ in general, is the skin. The largest internal organ is the liver. This organ has an average weight of 1.6 kilograms and is the heaviest. Skin is also the fastest-growing organ.

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4 responses to “Connective Tissue – Definition, Types, and Functions”

  1. shruti says:

    what are the types of connective tissues?

  2. Christa lee says:

    What is adipose tissue? Where is found in our body?

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