A Brief Description of the Eleven Major Organ Systems in the Body and Their Main Function
The eleven major organ systems, and brief descriptions of their functions, are as follows:
1. Integumentary – This system includes the skin and its appendages (hair, nails, and specialized sweat- and oil-producing glands). Its primary function is protection. For example, the skin protects the underlying tissue from invasion by harmful bacteria, bars entry of most chemicals, and minimizes the chances of mechanical injury to underlying structures.
2. Skeletal – The skeletal system includes bones and related tissues such as cartilage and ligaments, which provide the body with a rigid framework for support and protection. The skeletal system also makes possible the movements of body parts.
3. Muscular – The muscular system, consisting of the individual skeletal muscles, makes movement possible and generates the heat required for maintaining a constant core body temperature. Voluntary muscles are so called because their contractions are under conscious control. Involuntary or smooth muscle tissue is found in blood vessel walls, other tubular structures and in the lining of hollow organs such as the stomach and small intestine. Cardiac muscle is the specialized muscle tissue of the heart.
4. Nervous – The nervous system is composed of the brain, spinal cord and nerves. The nervous system makes possible communication between body functions, integration and control of body functions, and recognition of sensory stimuli.
5. Endocrine – The endocrine system is composed of specialized glands that secrete chemicals known as hormones directly into the blood. The organs of the endocrine system are sometimes called ductless glands. The endocrine system is similar to the nervous system in that it also provides communication, integration and control, but it does it in a slower and longer-lasting way by hormone secretion. Hormones are also the main regulators of metabolism, reproduction and other body activities. They play important roles in fluid and electrolyte balance, acid-base balance and energy metabolism.
6. Cardiovascular (Circulatory) – The cardiovascular system includes the heart, arteries, veins and capillaries. The primary function of this system is transportation. Transportation needs include continuous movement of oxygen and carbon dioxide, nutrients, hormones, and other important substances. This system also helps regulate body temperature by distributing heat throughout the body and by assisting in retaining or releasing heat from the body by regulating blood flow near the body surface. Specialized cells of the circulatory system can also become involved in immunity.
7. Lymphatic – The lymphatic system is composed of lymph nodes, lymphatic vessels and specialized lymphatic organs such as the tonsils, thymus and spleen. The lymph system moves fluids and certain large molecules from the tissue spaces around the cells and moves fat-related nutrients from the digestive tract back to the blood. It also plays a role in the functioning of the immune system, which is the defense mechanism of the body against disease.
8. Respiratory – The respiratory system includes the nose, pharynx, larynx, trachea, bronchi and lungs. Its primary function is to permit the movement of air into the alveoli, which are the tiny thin-walled sacs of the lungs. In these sacs, oxygen from the air is exchanged for carbon dioxide, a waste product, which is then carried to the lungs by the blood so that it can be eliminated from the body. The respiratory system is also involved in regulating the acid-base balance of the body.
9. Digestive – The digestive system is composed of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anal canal (primary organs), as well as the teeth, salivary glands, tongue, liver, gallbladder, pancreas and appendix (secondary organs). All of the organs of the digestive system work together to ensure proper digestion and absorption of nutrients.
10. Urinary – The urinary system includes kidneys, ureters, bladder and urethra. The primary function of this system is the elimination of waste from the body. Other organs of the body are also involved in the elimination of body wastes, such as the lungs and skin.
11. Reproductive (consisting of a male subdivision and a female subdivision) – The reproduction system is composed of gonads (testes), vas deferens, prostate, penis and scrotum in the male, and gonads (ovaries), uterus, fallopian tubes, vagina and mammary glands in the female. The purpose of this system is the procreation of life, insuring survival of humankind.
Source by Jayne Baer