Body Systems

• All life processes are performed by one or more body systems.

• A body system (organ system) is a group of organs that collectively performs an overall function.

• For example, digestion is performed by the digestive system, which includes the oesophagus, stomach, liver, pancreas, gallbladder and intestines.

• There are 11 main body systems, divided into four categories:

• Supporting, moving and protecting the body.

• Skeletal system

• Muscular system

• Integumentary system

• Maintenance of the body:

• Respiratory system

• Digestive system

• Circulatory system (cardiovascular system)

• Excretory system (urinary system)

• Lymphatic system (immune system)

• Continuation of life cycle.

• Reproductive system

• Coordination and regulation of other body systems.

• Nervous system

• Endocrine system

Life processes are performed by one or more body systems.

(Images: macrovector, Adobe Stock)

• The main functions of each body system are summarised in the following table.

• 
  

  Body System	Function
  Skeletal system	Supports and protects body; stores calcium; generates blood cells.
  Muscular system	Moves skeleton; aids movement of blood and other materials.
  Integumentary system	Covers and protects body’s internal organs; keeps water inside the body; regulates body temperature.
  Respiratory system	Exchanges gases between the blood and the external environment.
  Digestive system	Ingests (takes in) food, digests it (breaks it down) and absorbs it into the bloodstream.
  Circulatory system	Transports blood and materials around the body.
  Excretory system	Filters and removes metabolic wastes; removes substances found in excess in the blood.
  Lymphatic system	Helps preserve fluid balance and protects the body against disease.
  Reproductive system	Produces sex cells, enabling reproduction of organism.
  Nervous system	Detects and responds to stimuli; integrates the activities of other organ systems.
  Endocrine system	Regulates body functions using hormones.