Organ systems are formed by the association of organs, which are organised from tissues. This kind of organisation helps the organism to perform various activities more efficiently. A group of organs that work together to perform a particular function is known as an organ system. The human body has eight major organ systems.
1. The Eight Major Organ Systems
| Organ System | Main Parts | Main Role |
|---|---|---|
| Skeletal | Bones, cartilages, joints | Frame work for the body; gives shape and protects soft internal organs |
| Muscular | Skeletal, smooth and cardiac muscles | Body movements (with the skeletal and nervous systems); maintains posture |
| Digestive | Alimentary canal and associated glands | Converts complex food into simple forms; absorption of digested food |
| Respiratory | Nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, lungs | Exchange of respiratory gases; helps us to breathe |
| Circulatory | Heart, blood vessels, blood | Transports gases, nutrients, hormones and wastes |
| Nervous | Brain, spinal cord, sensory organs, nerves | Conduction and co-ordination |
| Endocrine | Endocrine glands | Produces hormones; maintains the internal environment |
| Excretory | Kidneys, ureters, urinary bladder, urethra | Removes nitrogenous wastes |