Animal Transport

Animal Transport

1. Blood composition

   • Red blood cells
     • Biconcave, disc-like cells - no nucleus, millions in each mm3 if blood, thin membrane. Also have a large surface area
       • Transport O2 around the body, contain mainly haemoglobin, which loads and unloads O2 in lungs and other regions f the body
   • White blood cells
     • Phagocytes
       • Much larger cells, have a large lobed nucleus
         • Engulf pathogens and other microqogransims that have infected us. Broken down with enzymes, then the products are absorbed
     • Lymphocytes
       • Same size as RBC, large spherical nucleus
         • Produce antibodies to destroy microorganisms - some persist in blood after infection, giving immunity to specific diseases
   • Platelets
     • Smallest cells, basically fragments of other cells
       • Release chemicals to make blood clot when we cut ourselves
   • Plasma
     • Yellow, liquid part of blood - mostly water but also contains sugars, salts, proteins and hormones
       • Carries blood cells around the body; dissolved nutrients, hormones, CO2 and urea as well. Also distributes heat around the body

2. Immune response to disease

   • Lymphocytes
     • Produce antibodies
       • Causes bacteria to stick togethe
         • Labels the pathogen for a phagocyte to target
           • Lysis of pathogen (burst)
             • Neutralise pathogens
     • Recognise antigens/foreign bodies found on the surfaces of invading bodies
       • Can produce specific antibodies
         • These antibodies make the pathogen safe, or label them as targets for phagocytes
           • Some of these cells stay in the body and provide immunological memory
             • Different antigens require specific antibodies
               • Note: lymphocyte memory cells mean that if the disease is contracted in the future, antibody production occurs much more quickly and in greater quantities
   • 1. Lymphocytes detect presence of pathogens, due to their antigens
     • 2. Lymphocytes divide into plasma cells and memory cells
       • Plasma cells produce antibodies, memory cells stay in blood and provide immunological memory
         • Antibodies are complementary in shape to the antigen
           • 3. Antibodies bind to the antigens, neutralising pathogens

3. Antibodies

   • Small proteins produces by lymphocytes
   • Antigens
     • Proteins attached to cells
   • Antibodies are broken down by protease enzymes

4. Vaccinations

   • Attenuated (changed forms of the disease) - lymphocytes produce memory cells
   • Dead microorganisms
   • Just antigens
   • Harmless bacteria genetically altered to carry the disease

5. Blood clotting

   • 1. Seepage of fluid (plasma out of blood vessels). Blood cells widen
     • 2. WBC move to the site to combat the germs
       • 3. Platelets in the blood help the blood clot, as when exposed to air, they release an enzyme, which converts a soluble protein to an insoluble fibrin
         • 4. The fibrin forms a mesh that traps RBC, creating a clot, which hardens to form a scab

6. Heart Structure

   • Vena Cava
     • Takes deoxygenated blood from the body to the heart
   • Right Atrium
     • Top chamber of the heart, contains deoxygenated blood
     • Left Atrium
       • Top chamber of the heart, contains oxygenated blood
   • Coronary arteries
     • Supply the heart with glucose and oxygen, for heart cell respiration
   • Atrio-ventricular valves
     • Control the passage of blood from an atrium to a ventricle, preventing back flow
   • Right ventricle
     • Bottom chamber of the heart, contains deoxygenated blood
     • Left ventricle
       • Bottom chamber of the heart, contains oxygenated blood
   • Pulmonary artery
     • Takes deoxygenated blood from the heart to the lungs
   • Semilunar valves
     • Prevent back flow. Only valves in the arteries
   • Pulmonary vein
     • Takes oxygenated blood from the lungs to the heart
   • Apex
     • Point of the heart
   • Septum
     • Wall of muscle that divides the two sides of the heart
   • Aorta
     • Takes oxygenated blood from the heart to the body
   • Tendons
     • Prevent the valves inverting

7. Heart rate increases during exercise , because the muscles need more oxygen for more aerobic respiration, to release more energy, to remove CO2 and prevent anaerobic respiration, therefore preventing the build up of lactic acid

8. Adrenaline

   • 'Fight or flight' hormone
     • Deeper breaths, heart beats faster, breathing rate increases
       • More oxygen to muscles for aerobic respiration

9. Coronary Heart Disease

   • Atheroma form when the smooth endothelium of an artery is damaged. Fat/cholesterol accumulates, building up to form a plaque, narrowing the lumen, increasing blood pressure. Could lead to a heart attack
   • CHD occurs when coronary arteries narrow, due to a build up of plaque/fat
     • Blood flow reduces/less O2 and glucose being delivered to the heart+increased blood pressure
       • Heart can't respire aerobically to release energy, so it respires anaerobically, leading to build up of lactic acid
         • Heart attack
   • Factors increasing chances
     • Heredity
       • High blood pressure - more strain on the heart
         • Diet - eating saturated fat raises cholesterol levels
           • Smoking - increases chance of blood clotting+raises blood pressure
             • Stress - raises blood pressure
               • Lack of exercise - exercise lowers blood pressure, and strengthens heart

10. Blood Vessels

    • Arteries
      • Thick strong walls to withstand pressure
        • Muscle fibres present in walls, to change the size of the lumen to control blood flow
          • Elastic fibres to stretch to accommodate large volumes of blood
            • Small lumen to maintain high pressure
    • Veins
      • Large lumen, allows a large volume of blood to flow
        • Blood pressure low, so they act as a reservoir
          • Valves prevent back flow
            • Run through large muscles to squeeze veins
    • Capillaries
      • Very small lumen,blood travels slowly, giving a chance for substances to diffuse
        • No elastic fibres, etc, between cells. Rapid diffusion - short diffusion distance
          • One cell thick;diffusion

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