Levels of Organisation

2.4 Levels of Organisation
Main organ systems in the human body:
Systems Functions and Organ involved
Endocrine system

The endocrine gland secretes hormones

Main function:

Coordinates body activities with the nervous system

Respiratory system

Trachea, nose, lungs and diaphragm

Main function:

Exchange of oxygen and carbon dioxide gases between the body and the external environment

Muscular system

Skeletal muscles, smooth muscles and cardiac muscles

Main function:

Contracts and relaxes to produce movements in different parts of the body

Male reproductive system

Testes, prostate gland and penis

Main function:

Produces sperm and male sex hormones

Female reproductive system

Ovary, uterus, Fallopian tube, vagina and cervix

Main function:

Produces ovum and female sex hormones

Lymphatic system

Spleen, lymph nodes and lymph vessels.

Main function:

Maintains balance of bodily fluids and prevents infectious diseases

Nervous system

Brain, spinal cord and peripheral nerves

Main function:

Detects and send information in the body, as well as coordinates body activities

Blood circulatory system

Heart, artery, vein and blood capillary

Main function:

Transports nutrients, respiratory gases and waste products

Digestive system

Mouth, oesophagus, stomach, liver, pancreas, small intestine and large intestine

Main function:

Digests food into a simpler form for easy absorption

Urinary system

Kidney, ureter, urethra and bladder

Main function:

Eliminates waste products such as urea and uric acid from the body

Skeletal system

Bone, cartilage, ligament and tendon

Main function:

Supports the body, protects the internal organs and provides a base for muscle adhesion

Integumentary system


Main function:

Protects the body from physical injury, infection and dehydration

Main systems in plants:

The plant system is divided into the shoot system and root system.

  • The shoot system consists of stems, leaves, shoots, flowers and fruits.
  • Stems and twigs are support systems that support the leaves at the vertical position to allow maximum absorption of sunlight during photosynthesis
  • Flowers are involved in the pollination process
  • The root system consists of all roots in a plant that function in absorbing water and mineral salts as well as providing support for plants