The body system is built on a biological ladder of ever increasing complexity. This biological ladder starts with chemicals joining to form known as Amino Acids. Amino Acids link to form peptide bonds or a polypeptide. This sequences of Amino Acids form deoxyribonucleic acids (DNA) a double helix staircase structure in cells (Here is a short animation of the process described).

Cells transform from general to tissue specific cells. Tissue specific cells work as a unit to create a larger structure called tissues. In the skim of things, like organs generate an organ system. Organ systems work together to create an organism (any living thing). The picture below outlines this narrative from top down.

From a Cell to an organism


What are the 11 organ systems?

Circulatory System     Skeletal System       Muscular System     Immune System                           Endocrine System           Integumentary System        Reproductive System                                            Respiratory System    Urinary System    Digestive System      Nervous System

Functions of systems:

Circulatory System

The circulatory system is a highway of blood vessels and veins from the head to the toes. This system carries vital nutrients and cells throughout the body. The circulatory system helps transport Endocrinol signals and hormones in the blood and is key to controlling body temperature. This system embodies the cardiovascular system. Just as highways are vital to the survival of an economy, the circulatory system is vital to the body.

Skeletal System

The skeletal system give the body structure. It consists of your bones, ligament, tendons and cartilage. Interestingly, inside the bone marrow is where red blood cells are manufactured. The skeletal system receives nutrients like Calcium through the circulatory system; giving it further strength. The skeletal system also gives the circulatory system red blood cells.

Muscular System

The muscular system is commonly known for giving the body motion. This system also gives the body insulation or the ability to retain heat.

Immune System

The immune system is the body second and final defense against pathogens or germs (first defense is integumentary system).

Endocrine System

The Endocrine System is a series of glands that secrete hormones into the blood stream or circulatory system. The hormones go to target organs and control growth, homeostasis(constant internal body temperature), metabolism and sexual development.

Integumentary System

Made up entirely of the skin, the integument is the largest organ of our body. The integument consists of hair follicles, sweat glands and nails. The integument protects our body from rapid dehydration and stores fat while producing vitamin D and hormones. Protects from the sun’s ultraviolet rays.

Reproductive System

The Reproductive system allows offspring to be produced. Male and female reproductive organs produce sex cells or gametes(diploid). Male reproductive system comprise of the testes, scrotum, penis, vas deferens and prostate. The female reproductive system is made of  ovaries, uterus, vagina and mammary glands.

Respiratory System

Respiratory system allows the body to exchange carbon dioxide for oxygen. This gas exchange occurs in the lungs via alveoli; sac in the the lungs.

Urinary System

In the urinary system, water and liquid waste are excreted while maintaining water balance in the body.

Digestive System

Helps the body breakdown and absorb food and nutrients. The body uses the food to create energy like ATP for its function. Part of the digestive system are the teeth, saliva glands, intestines, stomach and the rectum. Aiding the digestive system are the teeth, tongue, liver and pancreas.

Nervous System

The nervous system aids in communication. The brain, spinal cord and peripheral nerves facilitate motion and our perception of the environment.