Please enable JavaScript.

Coggle requires JavaScript to display documents.

Blood and Circulation (Heart Rate (Exercise: muscles produce more carbon…

- - - - Accelerator nerve:
        
        Increases heart rate
        
        Causes heart to beat with more force
        » increases blood pressure
      - Decelerator nerve:
        
        Decreases heart rate
        
        Reduces force of contractions
        » blood pressure returns to normal
      - These controls are part of reflex action
- - - - Weakened strain of actual microorganism
      - Dead microorganisms
      - Modified toxins of the bacteria
      - Just the antigens themselves
      - Harmless bacteria, genetically engineered to carry the antigens of a pathogen
- - - - KA 'surface area to volume ratio'
- - - - Deoxygenated blood leaves heart through pulmonary artery
      - Circulated through the lungs where it's oxidised
      - Oxygenated blood returns to heart through pulmonary vein
    - - Oxygenated blood leaves heart through aorta
      - Circulated through all other parts of body, where it unloads its oxygen
      - Deoxygenated blood returns to heart through vena cava
  - - - Blood travels more quickly to organs
      - Heart pumps blood twice
        » higher pressure
    - - Blood loses pressure as it goes through gills
      - Travels more slowly to other organs
  - - - Arteries: carry blood away from heart towards other organs
      - Veins: carry blood towards heart and away from other organs
      - Capillaries: carry blood through organs, linking arteries and veins
- - - - R vent. just pumps to lungs, L vent. pumps all over
      - Higher pressure required on left
        » wall of left ventricle is much thicker
    - - Can be stretched to receive blood
      - Can contract with enough force
    - - can contract and relax continuously without fatiguing
      - Has its own blood supply, KA the coronary circulation
        
        blood reaches muscle via coronary arteries
        
        Coronary arteries carry blood to capillaries that supply heart muscle with oxygen and nutrients
        
        Blood is returned to right atrium via coronary veins
  - - - Fatty substances can cut off bloody supply to an area of cardiac muscles
      - Affected muscle can no longer receive oxygen and glucose
        » Cannot respire and release energy
        » Unable to contract » heart attack
      - » Easily blocked by a build-up of fatty substances (inc. cholesterol) in their walls
    - - Heredity
      - High blood pressure—puts more strain of the heart
      - Diet—large amounts of sat. fats raises cholesterol levels
      - Smoking—raises blood pressure, blood clots more likely to form
      - Stress—raises blood pressure
      - Lack of exercise—regular exercise reduces blood pressure and strengthens the heart
- - - - Carries blood cells around the body
      - Carries dissolved nutrients, hormones, carbon dioxide and urea
      - Distributes heat around body
  - - - No nucleus—more haemoglobin packed into each cell
      - Biconcave shape: efficient exchange of oxygen in and out of cell
      - High surface area to volume ratio: large area for diffusion
      - Thin shape of the cell: short diffusion distance to the centre of the cell
    - - Transport of oxygen
      - Contains mainly haemoglobin
        
        Loads oxygen in lungs
        
        Unloads it in other regions of body
        
        Contains iron
        
        Combines with oxygen to form oxyhaemoglobin
        « high concentration of oxygen in surroundings
        
        Haemoglobin + oxygen ––in lungs––> oxyhaemoglobin
        
        Low oxygen concentration
        » oxyhaemoglobin ––in tissues––> haemoglobin
  - - - Same size as RBCs with large, spherical nucleus
      - Produce antibodies to destroy microorganisms
        
        Some persist in blood after infection and give immunity to specific diseases
      - Make chemicals KA antibodies
      - Antibodies:
        
        Soluble proteins that pass into plasma
        
        Pathogens eg. bacteria and viruses have chemical markers on surface, which antibodies recognise, KA antigens
        
        Stick to surface antigens and destroy pathogen by:
        
        Cause bacteria to stick together
        » phagocytes can ingest them more easily
        
        Act as label on pathogen
        » more easily recognised by a phagocyte
        
        Cause bacterial cells to burst open
        
        Neutralise poisons produced by pathogens
    - - Much larger than RBCs, with large spherical or lobed nucleus
      - Ingest and destroy bacteria and other microorganisms that have infected body
      - 70% of white blood cells
      - Conduct phagocytosis
        
        Ingest and destroy microorganisms
        
        Shape change
        
        Produce extensions of cytoplasm, KA pseudopodia
        
        These surround and enclose microorganism in a vacuole
        
        Phagocyte secrets enzymes into vacuole to break it down
    - - Skin cut
        
        Exposure to air stimulates platelets and damaged tissue to produce chemical
        
        This chemical causes fibrinogen (soluble plasma protein) to change into insoluble fibres of fibrin (another protein)
        
        Fibrin forms a network across the wound in which red blood cells become trapped.
        
        This forms a clot which prevents further loss of blood and entry of microorganisms that may be pathogens
        
        Clot develops into a scab which protects the damaged tissue while new skin grows
      - Fragments of large cells made in bone marrow