Organisation

• Cells

  Basic building blocks of living organisms, have a similar structure and function
• Tissues

  A group of cells which perform a specific function
• Organs


  A group of tissues which perform a specific function
• Organ systems


  A group of organs which work together
• Organ systems

  • Circulatory system
  • Respiratory system
  • Digestive system
• Cells make up tissues
• A group of tissues make up an organ
• A group of organs make up organ systems
• Animal tissues, organs and organ systems

  The structural and functional units of animals
• Risk factors

  • Diet
  • Exercise
  • Drug/alcohol consumption
  • Environment
  • Stresses
• Diseases are caused by an interaction of different factors
• Types of diseases

  • Non-communicable diseases
  • Communicable diseases
• Carcinogens

  • Chemicals
  • Ionising radiation
  • Viruses
• Communicable diseases

  • Pathogens: viral
  • Pathogens: 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
• The circulatory system has a double circulatory system: right ventricle to lungs, left ventricle to body
• Pacemaker


  Controls resting heart rate
• Alveoli


  Site of gas exchange in the lungs
• The 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
• The digestive system


  Function: to break down and absorb food
• Enzymes

  Work best at optimum temperature and pH
• 'Lock and Key' theory


  Explains how enzymes and substrates interact
• Enzymes in the digestive system

  • Carbohydase (amylase)
  • Protease
  • Lipase
• Bile

  Bile is alkaline. It is used to neutralise stomach acid. Allows optimum pH. Aids lipid breakdown
• Plant tissue structure

  Plant tissues, organs and organ systems
• Transport systems

  Plant tissue structure
• Phloem


  Transports sugars via translocation
• Xylem


  Transports water via transpiration
• Root hair cells

  Substances absorbed at the root
• Substances moved up the stem

  • Substances moved up the stem via the xylem and phloem
• Transpiration

  Water evaporates and exits the plant via the stomata
• Factors affecting transpiration rate

  • Temperature
  • Humidity
  • Wind speed
  • Light intensity
• Adapted for exchange

  Thin wall, large surface area, lots of mitochondria
• Leaf structure

  Plant organ
• 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
• Meristem tissue

  Where cell division occurs, contains stem cells