How the Body Works

The human body is a complex organism made up of many systems that work together. The specific sciences that study the body are called anatomy and physiology. Anatomy refers to the study of the structures, whereas physiology focuses on how they work. These are both branches of biology.

The science of the body can be studied at five different organizational levels. The smallest level is chemical, which refers to atoms, molecules, and even parts of atoms. The next largest level is the cell, or the basic unit of life. Cells are made up of many different kinds of molecules and atoms. Many similar cells together create tissue, and an organ is two or more types of tissue that work together. Multiple organs that share similar purposes make up organ systems. The largest organizational level is the organism, or the human body as a whole.

There are eleven organ systems in the human body.

The cardiovascular system consists of the heart, blood vessels, and blood. It carries oxygen and nutrients around body and transports carbon dioxide away. The heart pumps blood through blood vessels to achieve this.

The respiratory system includes the lungs and passageways that carry air. It obtains oxygen from the air and exhales the waste carbon dioxide. It helps transmit these things to and from the blood.

The integumentary system is a fancy name for skin, hair, and parts of skin like oil glands. These things protect the body, feel sensations, and help regulate temperature.

The brain, sense organs, nerves, and spinal cord make up the nervous system. The nervous system is the main control center of the body, responding to changes, controlling muscles, and regulating the body.

The muscular system is simply made up of muscles and tendons. This is what causes the body to move.

Many different organs are included in the digestive system, like the stomach, intestines, liver, and mouth. They work together to break down food and eliminate waste.

The urinary system is the bladder, urethra, kidneys, and ureters. It eliminates wastes in liquid form and also helps regulate the levels of fluids, minerals, and other things.

Reproductive systems are vastly different in men and women. The organs, such as ovaries, testes, and mammary glands, release hormones and create sperm or eggs for reproduction.

The endocrine system is one of the less known organ systems. It includes the structures that make hormones, including the pancreas, pituitary gland, ovaries, and more. Hormones help to keep body activities functioning at correct levels.

Bones, cartilage, and joints are all parts of the skeletal system. They provide structure for the body, store minerals, protect organs, and are an essential part of movement.

The lymphatic system includes the spleen, tonsils, lymph nodes, and other structures. It helps regulate the levels of fats and protein in blood.

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