Various Types of Systems in the Human Body

Also known as: Cardiovascular system

Description: The circulatory system uses blood to deliver oxygen and nutrients and remove carbon dioxide and wastes from the organs and tissues of the body. In addition to the blood, the circulatory system consists of the heart, which pumps the blood throughout the system, and blood vessels (arteries, veins, and capillaries) that carry the blood. Oxygen and carbon dioxide are exchanged when blood passes through the lungs, and wastes are removed when blood passes through the kidneys.

Also known as: Gastrointestinal, GI tract

Description: The digestive system extends from the mouth to the anus. Beginning with mastication by the teeth, it is responsible for digesting food, absorbing nutrients, and expelling unusable food waste via the anus. In addition to the main organs (stomach and intestines) there are accessory organs that secrete digestive juices and bile to assist with digestion such as the pancreas, gall bladder, salivary glands, and liver.

Description: The endocrine system is an organization of glands which secrete chemicals, called hormones, to communicate with other glands and organs of the body. Endocrine hormones travel in the blood to relay messages between anatomical systems and act as feedback mechanisms to turn biological processes on and off.

Description: The integumentary system is the protective layer of skin, hair, and nails on the body. The skin also contains receptors for the sense of touch. This system is an important barrier to pathogen entry to the body, keeps the other systems contained within the body, and assists in temperature regulation.

Description: The lymphatic system is a drainage system for excess tissue fluid and is part of the body's defense system. Consisting of lymph vessels, lymph nodes, and the lymph, water and nutrients can be reabsorbed into the blood and infectious particles can be diverted to and attacked at sites concentrated with immune cells.

Description: The immune system is the body's defense system. It consists of cells made by the thymus and bone marrow that utilize both the circulatory and lymph systems to protect and defend against infectious agents at or near the site of entry. Other systems help achieve full protection by offering barriers to the entry of foreign particles such as the integumentary system, respiratory system, and special tissue in the digestive tract. Organs also associated with the system are the spleen, appendix, and tonsils.

Description: The nervous system consists of nerve fibers, the spinal cord, and the brain. Peripheral nerves relate sensory input to the brain by electrical conduction that travels up the spinal cord. In turn, the brain processes the information and induces a mechanical response by relaying signals back to the peripheral nerves. The signaling within the brain is achieved by chemicals called neurotransmitters. The nervous system is thus broken into two parts

Description: The muscular system is responsible for movement of the body and strength. It consists of skeletal muscle and tendons that attach them to the skeletal frame. Movement is achieved through contraction and relaxation of complimentary muscle groups. In the human body there are more than 600 different skeletal muscles.

Also known as: Skeleton

Description: The skeletal system is made up of bones connected via cartilage and ligaments. The bone structure provides the support and frame for the body as well as providing attachment points and joints on which the muscles act. The bones contain marrow, which is necessary for the production of blood cells. The bones also store calcium, a necessary mineral for cellular processes.

Description: The respiratory system takes in oxygen by inhalation and releases carbon dioxide by exhalation. The breathing system consists of the upper and lower respiratory tracts including the lungs. Oxygen taken into the alveoli of the lungs is absorbed by the blood and exchanged for carbon dioxide. A mucus lining of the upper respiratory tract prevents the entry of foreign particles and pathogens. A muscle underneath the lungs, called the diaphragm, as well as the intercostal muscles along the ribcage, aid in the contraction and relaxation of the lungs during breathing.

Also known as: Excretory system, Renal urinary tract

Description: The urinary system is responsible for the body's fluid balance. Consisting of the kidneys, bladder, and urethra the system is involved in maintaining water and electrolyte levels. The kidneys contain a complex network of blood vessels and capillaries to filter wastes into the bladder for excretion in the form of urine.