Principles of Organisation

• Cells


  Fundamental units of life, each designed to perform specialised functions through a process called DIFFERENTIATION
• Differentiation


  Cells specialise to perform specific functions
• Tissues


  Groups of similar cells working together to carry out a particular function.
• Tissues in mammals


  • Muscular tissue: Responsible for movement by contracting and relaxing
  • Glandular tissue: Produces and releases substances like enzymes and hormones
  • Epithelial tissue: Covers the surfaces of the body, such as the inside of the gut
• Organs


  group of different tissues working together to carry out a particular function.
• Heart


  • Organ that contains muscular tissue for PUMPING BLOOD around the body
• Organ Systems


  Groups of ORGANS working together to carry out a particular function.
• • Muscular tissue


  Responsible for movement by contracting and relaxing
• Glandular tissue


  Produces and releases substances like enzymes and hormones
• Epithelial tissue


  Covers the surfaces of the body, such as the inside of the gut
• cells always start off as undifferentiated (has no function).

  when genes are switched on, they then become specialised to carry out a specific job.

  e.g. specialised muscle cells
• The digestive system is considered an organ system because it consists of a group of organs that work together to perform the common function of digesting and absorbing our food.

  For e.g: the pancreas releases digestive enzymes (helps break down the food molecules), while the small intestine absorbs the nutrients.
• organelles -> cells -> tissues -> organs -> organ systems