Levels of organization of human body: How is human body organized

Levels of Organization of Human Body: How is Human Body Organized?

We can correlate the organization of the human body with an analogy in the English language as a sentence is formed by the organization of the different types of smaller units. To make the concept even more precise, we can dissect a sentence into a group of words composed up, then word into different alphabets. So, in a nutshell, we can conclude that a group of different alphabets make a word, and a combination of words makes a complete sentence. Similar is the case fact when it comes to the organization of the human body.

In general, there are five different levels of organization of the human body. Those five different levels of organizations are:

  1. Chemical Level of organizations:- Chemical level of organization of the body says that a body is the aggregate form of different types of chemical substances like atoms and molecules. The human body is mainly formed by organic compounds like carbon, hydrogen, oxygen, nitrogen, phosphorus, chlorine, etc. Except for these chemical atoms, many other complex forms of molecules give the body accurate and organized structures. Some of such complex molecules include DNA (Deoxyribonucleic acid), RNA (Ribonucleic acid), etc.
  2. Cellular Level of Organization:- The organization is a bit more complex than the chemical level of organization is the cellular level of organization where different kinds of atoms and molecules combine to form the cell. The cell is so basic unit of the organization of the body that is often called the structural and functional unit of life. There are many types of cells in the body like the cardiac cell, smooth muscle cell, etc.
  3. Tissue Level of Organization:- Tissue is formed by a group of similar kinds of cells. The tissue level of organization is higher than both the chemical and cellular level of organization. These tissues give rise to the organ level of organization in the body.
  4. Organ Level of Organization:- Organs are the bigger units than the previously discussed three levels of organization( chemical level, cellular level, and tissue level) that can be noticed with the naked eyes. The different organs of the body organize together to form complete and functional body systems like the heart. Its associated organs include the circulatory system, lungs, windpipe, the respiratory System’s organs, etc.
  5. System Level of Organization:- The system level of organization in the body is formed by the combination of different related organs of the body. Eleven systems in the body make a body compete. All of those 11 systems of the body are explained below in detail:


  1. Integumentary System – Integumentary System is composed of skin and skin derivatives such as hair, nails, sweat glands, and oil glands. The primary function of this Systesystemo protect the body, help to regulate the body, eliminate the body waste, detect the sensation, make vitamin D
  2. Muscular System:- The System of the body that helps move the body and is composed of muscles attached to the bones is known as the muscular System:- The System of the body that is made up of the bones, joints are their associated organs and helps in giving framework and support to the body is known as the skeleton system.
  3. Nervous System:- The System of the body that is composed of the brain, spinal cord, nerves, and particular organs and helps in detecting the changes occurring inside and outside the body and helps to interpret the changes is called the nervous System.
  4. Endocrine System:- The System of the body that produces the chemical substances called hormone from the different glands of the body like the pituitary gland, pineal gland, pancreas, thymus, ovary, adrenal gland, etc. and helps in controlling and regulating the body activities are known as the endocrine System.
  5. Lymphatic and Immune System:– The System of the body that is composed of lymphatic fluid, lymphatic vessel, spleen thymus, lymph node, and tonsil and helps in returning the proteins and fluid to blood and carries lipid from the gastrointestinal tract to blood. The lymphatic System is formed by the lymphatic cells, and they protect the body against disease-causing organisms.
  6. Cardiovascular System:– Cardiovascular System is composed of blood, the heart, and blood vessels. The cardiovascular System’s functions are to pump blood through the blood vessel; blood carries oxygen and nutrients to the blood and carbon dioxide and other waste away from the body, helps maintain acid-base balance, fluid and water content, and protects the body from diseases.
  7. Respiratory System:- The components of the Respiratory System are the lungs, air passageways, trachea, and bronchial tubes. The respiratory System’s function is to transfer the oxygen from the air inhaled into the blood and carbon dioxide from the inhaled air to outside in the environment, which helps in the production of sound by the help of the air going through the vocal cord. It also helps to maintain acid-base balance in the body.
  8. Digestive System:- Digestive System is composed of the gastrointestinal tract, a long tube that includes the mouth, esophagus, stomach, small and large, anus, and other accessory organs such as the salivary gland, liver, gallbladder, and pancreases. Its function is to do the physical and chemical breakdown of the food, absorb nutrients from it, and eliminate the solid wastes of undigested food outside the body.
  9. Reproductive System:- It is composed of the gonads (testes in males and ovaries in females) and the associated organs like the uterine tube, uterus, vagina in females, and epididymis, ductus deferens, and penis in males. The function of the reproductive System is to produce gametes that fertilize to form a new organism. Gonads also produce hormones that help to regulate reproduction and other parts of the body.
  10. Urinary System:- It is composed of kidneys, ureters, urinary bladder, and urethra. The functions of the urinary System include the production, storage, and elimination of urine, elimination of the wastes, and regulation of the chemical composition of the blood. It is equally essential for the acid-base and the chemical balance in the body.

Thus, the organization of the human body starts from the most more straightforward form of atoms and molecules and ends into the system level of organization that ultimately leads to the formation of a complete and functional human body.