Biology - Module 5

Biology - Module 5

1. HEART PROBLEMS

   • Hole in the heart
     • Oxygenated and deoxygenated blood is allowed to mix as blood can move directly from one side of the heart to another through hole in the septum.
     • The blood leaving the heart from the atria carries less oxygen. As a result, muscles receive less oxygen and therefore less energy.
     • All unborn babies have this hole. They do not need a double circulatory system as their lungs do not function before they are born.
       • When born, this hole closes. If this does not occur, the baby is born blue.
   • Damaged or weak valves
     • Blood could flow backwards and with less pressure which means reduced pressure, leading to poor circulation.
     • Artificial valves can be used as a replacement.
   • Blocked coronary artery
     • If blocked, less blood flows to the heart and it can lead to a heart attack.
     • By-pass surgery uses veins transplanted from other parts of the body. These take blood from the aorta, avoiding the blocked artery.
   • Heart assist devices
     • Reduced work done by heart muscles.
     • Often used for those people awaiting a heart transplant.
     • Advantages: Improves quality of life, keeps patients alive, no problems with waiting for a donor or tissue match, no need for open heart surgery, no risk or rejection.
     • Disadvantages: Valves and pacemakers might need replacing.
   • Artificial Pacemakers
     • These are implanted under the skin and are a substitute for a natural pacemaker.

2. BLOOD GROUPS, CLOTTING & DONATION

   • Haemoglobin = The chemical you find in red blood cells, carries the oxygen.
   • Platelets = Fragments of cells that are involved in blood clotting.
   • White Blood Cells = They are involved with defending your body against disease
   • Red Blood Cells = Contain haemoglobin, carry oxygen around the body.
   • Plasma = 80% water, liquid part of the blood.
   • Blood Donor = Somebody who donates their blood.
   • Blood Transfusion = When you receive blood - The process in which the blood donor's blood is put into your body.

3. CLOTTING

   • Prevents entry by pathogens and stops you losing too much blood.

4. HAEMOPHILIA

   • An inherited disease in which blood fails to clot.
   • Queen Victoria suffered from Haemophilia.

5. PREVENTING BLOOD CLOTS

   • Anti-coagulant drugs e.g. warfin, heparin and asprin, can help to thin the blood and prevent clotting in vessels.

6. BLOOD CLOTTING = CASCADE PROCESS

   • Cut on the skin
     • Platelets exposed to air.
       • Several chemical reactions.
         • Meshwork of fibrin forms.
           • Clot forms

7. DONATING BLOOD

   • The blood donated by the donor must be compatible with the recipient for ma successful transfusion.
   • If it not compatible then agglutination (blood clumping) is caused. This is dangerous for the patient.

8. BLOOD GROUPS

   • Your blood group depends on the presence or absence of aggluinins.
     • 2 proteins n the surface of RBCs (antigen A or B)
     • 2 anti-bodies in blood plasma (serum) (anti-A or anti-B)
   • Donation of blood is based on the antigens on the surface of your RBCs.
   • Receipt of blood is based on the antibodies in your plasma.

9. RESPIRATORY SYSTEM

   • Inspiration = Forcing air into the lungs.
   • Expiration = Forcing air out of the lungs.
   • Breathing = The exchange of gases between the lungs and surrounding air.
   • Respiration = The breakdown of glucose to release energy.

10. BREATHING

    • Breathing In
      • The intercostal muscles contract to lift the ribs up and outwards.
      • The diaphragm contracts ad moves down.
      • The volume inside the chest increases. Pressure is lower inside the thorax than out.
      • This causes air to rush into your lungs and they inflate.
    • Breathing out
      • The intercostal muscles relax to lower tbs down and inwards.
      • The diaphragm relaxes and move up.
      • The volume inside the chest decreases. Pressure is higher inside the thorax than out.
      • This causes air to rush out of the lungs and they deflate.

11. ALVEOLI ADAPTATIOMS

    • Good blood supply - maintains concentration gradient
    • Large surface area - provided my many small alveoli.
    • Permeable lining - allows gases to pass across.
    • Moist surface - makes diffusion easier.
    • Thin lining (one cell thick) - provides diffusion pathway.