Organisation

• Cells


  Basic building blocks of living organisms
• Organ systems


  A group of organs which work together
• Organs


  A group of tissues which perform a specific function
• Tissues

  Cells make up tissues
• Cells

  • Have a similar structure and function
• Principles of organisation

  1. Cells

  2. Tissues

  3. Organs

  4. Organ systems
• Organ systems

  • Circulatory system
  • Respiratory system
  • Digestive system
• Each cell have a specific function
• A group of tissues which perform a specific function make up an organ
• A group of organs which work together make up organ systems
• Carcinogens

  • chemicals
  • ionising radiation
  • viruses
• Factors that increase the chance of disease

  • Diet
  • exercise
  • drug/alcohol consumption
  • environment
  • stresses
• Diseases are caused by an interaction of different factors
• Pathogens

  • viral
  • bacterial
• Different types of diseases can interact, e.g. viruses can trigger cancers
• Main components of blood

  • plasma
  • white blood cells
  • red blood cells
  • platelets
• Blood vessels


  • arteries
  • veins
  • capillaries
• Main blood vessels of the heart

  • pulmonary vein
  • pulmonary artery
  • aorta
  • vena cava
  • coronary arteries
• Double circulatory system


  right ventricle to lungs, left ventricle to body
• Pacemaker


  controls resting heart rate
• Lungs adapted for exchange

  • capillary network
  • large surface area
  • thin
  • moist
• Oxygen enters blood vessels at alveoli


  Transported to the heart via the pulmonary vein
• Function of the digestive system

  to break down and absorb food
• Enzymes

  Work best at optimum temperature and pH
• Types of enzymes

  • Carbohydrase (amylase)
  • protease
  • lipase
• Bile


  Alkaline, used to neutralise stomach acid, allows optimum pH, aids lipid breakdown
• Plant tissues, organs and organ systems


  The different components that make up a plant
• Transport systems

  • Phloem
  • Xylem
• Plant tissue structure

  • Stem
  • Leaf
  • Root hair cells
• Substances absorbed at the root

  Move up the stem
• Substances move up the stem

  Via the xylem and phloem to the leaves
• Transpiration


  The process of water evaporating and exiting the plant via the stomata
• Transpiration rate

  • Depends on temperature, humidity, wind speed and light intensity
• Root hair cells

  • Adapted for exchange: thin wall, large surface area, lots of mitochondria
• Phloem


  Transports sugars via translocation
• Xylem


  Transports water via transpiration
• Xylem

  • Dead, hollow cells, strengthened with lignin
• Phloem


  • Made from elongated living cells
• Stomata and guard cells

  Control the rate of gas exchange and transpiration
• Leaf structure


  • Stomata and guard cells - gas exchange
  • Xylem and phloem - transport
  • Palisade layer - top of leaf, contains chloroplasts for photosynthesis
  • Lower epidermis- contains stomata
  • Spongy mesophyll - facilitate diffusion of gases, loosely packed cells