Human Body Systems
organs
A combination of two or more tissues that work together to perform a specific function in the body.
organ systems
A group of organs that work together to perform an important function.
tissues
A group of similar cells with a specific function (four types = muscle, nervous, connective, epithelial).
organism
A living thing; anything that can carry out life processes independently.
immune system
A system of cells, tissues and organs that produces specialized white blood cells that protect the body from viruses, bacteria, and tumor cells. It defends the body from foreign invaders that could cause illness or disease.
reproductive system
A system of organs involved in producing offspring. The body system responsible for the continuation of the species. This system is composed of structures that form gametes, enable fertilization, support the development of the fetus, and enable the birth of a child.
respiratory system
A system of organs that exchanges gases between the body and the environment; it consists of the nose, pharynx, larynx, trachea, bronchi, bronchioles, lungs and alveoli.
integumentary system
A system of organs that forms a protective covering on the outside of the body. Components inlcude skin, hair, nails and sweat and oil glands.
muscular system
A system of organs that moves your body, produces body heat and helps it perform functions. Consists of skeletal muscles, tendons that connect muscles to bones, and ligaments that attach bones together to form joints. The three types of muscle are smooth, skeletal, and cardiac.
skeletal system
A system of organs that protects and supports body organs and provides a framework the muscles use to support movement. It is made up of bones, joints, cartilage, tendons and ligaments.
endocrine system
A system of organs that uses glands to secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells. It assists the body in maintaining homeostasis.
lymphatic system
A system of tubes throughout the body that carry lymph, which is liquid that flows out of the circulatory system. The lymphatic system also has lymph nodes, where white blood cells will fight off bacteria that have invaded the body.
organelles
A tiny cell structure that carries out a specific function within the cell.
metabolism
All of the chemical reactions that occur within an organism.
cells
The basic unit structural and functional unit of life. All living things (except viruses) are made of cells.
digestive system
The body system the breaks down food and absorbs nutrients.
homeostasis
The process by which organisms maintain a relatively stable internal environment.
nervous system
The system of organs responsible for communication and control; it transmits impulses, responds to change and exercises control over all parts of the body.
excretory system
The system that removes waste from your body and controls water balance (liquid waste system = urinary system). For example, the kidneys are organs that filter liquid waste, the lungs remove gas waste such as carbon dioxide, and the skin removes waste in the form of sweat.
circulatory system
This organ system works as the transportation highway for the body. It consists of the heart, blood, and blood vessels. It transports substances such as oxygen, carbon dioxide, and nutrients in the body (also called the cardiovascular system).