B4 biology AQA

• The Human Circulatory System


  A double circuit. Blood must pass through heart 2 times before completing one whole circuit.
• Pulmonary Circulation

  Blood pumped from heart to lungs and back to the heart
• Systematic Circulation

  Blood pumped from heart to body and back to the heart
• Red Blood Cells

  Carry Oxygen
• White Blood Cells

  Defend the body against pathogens
• Platelets

  Control Blood Clotting
• Plasma

  Carries Dissolved Substances
• Shape Of Red Blood Cells

  Flattened, Biconcave, Disc Shaped
• Haemoglobin

  Pigment that makes the blood red
• Nucleus

  Red Blood Cells don't have one of these
• No Nucleus

  Disc Shaped

  Smaller than the other type

  Red Blood Cells
• Have a nucleus

  Irregular shape

  Large than the other type

  White Blood Cells
• Scabs

  Prevent pathogens entering the body
• Pale Yellow in Colour

  90% Water

  Plasma
• Function of heart

  Pump blood around body
• Coronary Arteries

  Blood vessels on the outside of the heart
• Pulmonary Artery

  Carrying Deoxygenated blood from the heart to the lungs
• Valves

  Prevent back flow of blood when ventricles relax
• Aorta

  Artery carrying blood to the body
• Pulmonary Vein

  Carrying oxygenated blood from the lungs to the heart
• Vena Cava

  Vein carrying blood from body back to heart
• Between Atria and Ventricles

  There a valves
• Atria (Multiple Atrium)

  Have thin walls as only pump blood to ventricles
• Ventricles

  Have thick muscular walls so can pump blood out of heart
• Left ventricle

  Has the thickest walls as pumps blood to WHOLE BODY
• Arteries

  Have thick walls because they carry blood under pressure
• Veins

  Have thin walls because they carry blood under low pressure
• Capillaries

  Smallest blood vessels that form extensive networks
• Photosynthesis

  process by which plants use the sun's energy to convert water and carbon dioxide into sugars
• Transpiration

  Evaporation of water from the leaves of a plant
• Factors affecting rate of transpiration

  Light, Temperature, Wind, Humidity
• Potometer

  The device used to measure the amount of transpiration occurring from a plant
• Xylem

  Plant tissue that transports water and minerals from the roots to the leaves / flowers
• Phloem

  Living vascular tissue that carries sugar and organic substances throughout a plant
• Palisade Cells

  Oblong cells in leaves that are located directly under the upper epidermis and contain chloroplasts for maximum sunlight
• Spongy mesophyll

  Loose tissue beneath the palisade layer of a leaf; has many air spaces between its cells for CO2 to reach palisade cells for photosynthesis
• Guard Cell

  Pairs of cells that surround stomata and control their opening and closing.
• Stomata

  Small openings on the underside of a leaf through which oxygen and carbon dioxide can move
• Waxy Cuticle

  Forms a waterproof layer to stop water loss due to photosynthesis
• Gas Exchange

  supplies oxygen for cellular respiration and disposes of carbon dioxide