Human Anatomy Body Systems

Skeletal System The human skeleton consists of both fused and individual bones supported and supplemented by ligaments, tendons, muscles and cartilage. It serves as a scaffold which supports organs, anchors muscles, and protects organs such as the brain, lungs and heart

Muscular System The muscular system is the largest system in the body. Muscles are located in practically every region of the human body. The muscular system is made up of tissues that work with the skeletal system to control movement of the human body.

Digestive System The digestive system is one of the most complex systems of the body. The digestive system is made up of organs that break down food into vitamins, minerals, protein, carbohydrates, and fats, which the body needs for energy, growth, and repair.

Nervous System The nervous system is a network of specialized cells that communicate information about an organism’s surroundings and itself. It processes this information and causes reactions in other parts of the body. It is composed of neurons and other specialized cells called glial cells (plural form glia) that aid in the function of the neurons.

Lymphatic System The lymphatic system filters fluid from around cells. It is an important part of the immune system. The lymphatic system consists of organs, ducts, and nodes.

Endocrine System The endocrine system is made up of a group of glands that produce the body's long-distance messengers, or hormones. The endocrine system is instrumental in regulating mood, growth and development, tissue function, and metabolism, as well as sexual function and reproductive processes.

Circulatory System The circulatory system is an organ system that passes nutrients (such as amino acids and electrolytes), gases, hormones, blood cells, nitrogen waste products, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis. This system may be seen strictly as a blood distribution network, but some consider the circulatory system as composed of the cardiovascular system, which distributes blood, and the lymphatic system, which distributes lymph.

Urinary System The urinary system is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the bladder, the urethra, and the penis in males.

Immune System The immune system is a network of cells, tissues, and organs that work together to defend the body against attacks by “foreign” invaders.

Integumentary System The integumentary system is the organ system that protects the body from damage, comprising the skin and its appendages (including hair, scales, and nails). The integumentary system has a variety of functions; it may serve to waterproof, cushion and protect the deeper tissues, excrete wastes, regulate temperature and is the attachment site for sensory receptors to detect pain, sensation, pressure and temperature. In humans the integumentary system additionally provides vitamin D synthesis.

Respiratory System The respiratory system is a biological system consisting of specific organs and structures used for the process of respiration in an organism. Respiration takes place in the respiratory organs called lungs. The passage of air into the lungs to supply the body with oxygen is known as inhalation, and the passage of air out of the lungs to expel carbon dioxide is known as exhalation; this process is collectively called breathing or ventilation.

Reproductive System The reproductive system is the system that allows for the continuation of the human species. This system is different in both males and females.