B4: Organising animals and plants

• Blood


  Transports substances around the body

  
• Red blood cells


  Blood cells that carry oxygen from the lungs to the body cells.

  
• White blood cells


  Blood cells that perform the function of destroying disease-causing microorganisms

  
• Platelets


  Small fragments of cells in the bloodstream that help the blood to clot when there is a wound

  
• Blood vessels


  Tubelike structures that carry blood throughout the body

  
• Arteries


  Carry oxygenated blood away from the heart and to the body

  
• Veins


  Carry deoxygenated blood to the heart from the body

  
• Capillaries


  Small vessels which connect veins and arteries

  
• Vena cava


  Brings deoxygenated blood from the body into the heart
• Heart


  A hollow, muscular organ that pumps blood throughout the body.

  
• Pulmonary artery


  Takes deoxygenated blood to the lungs
• Pulmonary vein


  Brings oxygenated blood from the lungs
• Aorta


  Carries oxygenated blood around the body
• Alveoli


  Small air sacs that are attached to bronchioles and allow gas exchange to take place
• Three adaptations of the alveoli to make gas exchange efficient:

  •Capillaries are one cell thick wall --> allows gases to easily pass through

  •There are many alveoli --> increases surface area of gas exchange

  •They are moist --> gases can dissolve, so they diffuse more easily
• Translocation


  Movement of sugars in a plant, and occurs in the phloem
• Transpiration


  Movement of water in a plant, and occurs in the xylem
• Name 4 factors that affect the rate of transpiration

  •Light intensity --> brighter = higher rate

  •Temperature --> warmer = higher rate

  •Air flow --> more windy = higher rate

  •Humidity --> less humid = higher rate