More Biology Unit 1

Coronary Heart Disease
1. Atheroma
  1. The build up of fatty acids such as cholesterol and other lipids in the lining of the artery wall.
  2. The lumen of the artery is narrower and so may restrict blood flow to the coronary artery
2. Thrombosis
  1. This is the clotting of blood in the arteries.
    1. This, again, narrows the lumen and may even block the lumen of the coronary artery
      1. Which, again, restricts bloodflow
3. Aneurysm
  1. This is a blood-filled balloon like swelling of the coronary arteries
    1. If this pops, it could lead to severe blood loss
4. Mycardial infarction
  1. This is the death of a heart muscle, in other words a heart attack
  2. It occurs when insufficient oxygen and glucose are supplied via the coronary arteries to the heart cells.
  3. They can't respire and so the heart muscle will die
Lung Disease
1. We know that gas exchange occurs by diffusion
  1. Therefore, anything that affects the rate of diffusioni.e. slows it down, will slow down the rate of respiration and so less ATP will be prduced and the individual will have less energy.
2. Asthma
  1. This is caused by allergens
    1. Smoke
    2. Pollen
  2. It's where the airways become narrow and this causes less oxygen to enter the lungs per breath
    1. 1. The muscles in the bronchi contract so the diameter of the airways is reduced.
      1. More mucus is secreted by the cells that line the bronchi and this also narrows the airways
        A chemical called histamine is released which causes the swelling of the bronchi
        This reduces the airways further
        Less oxygen will diffuse into the blood and so the rate of respiration will be lower.
  3. Consequences:
    1. Breathing is made more difficult
      1. Wheezing sounds as air is forced out through narrow airways
        Weaker patient
  4. Treatment
    1. Patients are given inhalers that are drugs that widen the airways again
      1. Avoding the allergen
3. Pulmonary Fibrosis
  1. This is where the alveolar epithelium becomes thicker.
    1. The diffusion pathway is longer and so there is a lower rate of diffusion
      1. The elasticity of the lung is reduced. It doesnt inflate or deflate properly
        The fact that it doesnt deflate properly is a problem because it means the stale air in your lungs arent removed.
        This reduces the concentration gradient and reduces the rate of diffusion
        Scarring may also cause a smaller surface area
  2. This may cause shortness of breath, especially during exercise
    1. This is because the volume of the lung is reduced, so less oxygen can diffuse through and so there is a lower rate of respiration, so less ATP is produces and less energy is released.
  3. Causes: Inhaling lots of fine dust over long periods of time
    1. e.g. working in the mining industry
4. Pulmonary Tuberculosis
  1. Caused by a bacterium called mycobacterium and is passed on through inhalation
    1. i.e. when the infected person sneezes, coughs, talks etc.
  2. Symptoms;
    1. Coughing up blood
      1. Chest Pain
        Fever
  3. In the lungs, the bacteria multiply
    1. The immune system responds and the bacteria are engulfed and are encased in a granuloma
      1. Some bacteria are destroyed, but some remain dormant
        A few years later, they may become active again, abdwukk multiply
        They destroy the alveoli and capillary walls. Can lead to the formation of scar tissue
  4. Antibiotics are the treatment
5. Emphysema
  1. Said to be caused by tobacco
  2. This is caused when you get fewer, larger alveoli
    1. This reduces the surface area and leads to a lower rate of diffusion
  3. The elastic tissue in the alveoli is reduced, making ventilation, especially breathing out difficult.
  4. Shallow breathing
    1. Weakness and fatigue
Immunology
1. Pathogens:
  1. Virus
  2. Fungi
  3. Bacteria
  4. Release toxins
  5. Damaging cells of the host
  6. We can prevent their entry by:
    1. Having our skin; it acts as a barrier
    2. Tears: Contain a digestive enzyme
    3. Nasal hairs: traps pathogens
  7. Pathogens may enter through the gas exchange system or the digestive system
2. Non-specific immunity
  1. Phagocytosis
    1. The phagcytes recognise the antigen on the bacteria as a non-self antigen
      1. The phagcytes engulf the bacteria
        Traos it in a vacuole called the phagosome
        Lysosomes attatch to it and releases its digestive enzymes
        This destroys the bacteria and its products are digested by the cell
3. Specific immunity
4. Antigen: a complex molecule that triggers an immune response
  1. May be found on the surface of your own cell
    1. On the surface of a virus
      1. On the surface of a bacterium
        On it's own
        On a transplant organ
  2. You have your own self antigens so that you're able to recognise foreign ones
Risk
1. Cancer
  1. Exposure to too much sun
  2. Obesity
  3. Cigarette smoking
  4. Stress
  5. Lack of exercise
2. CHD
  1. High blood pressure
    1. The walls of your arteries get thicker, which narrows your lumen
      1. Your heart has to work harder to pump blood around your body
        May lead to heart failure
        It also increases your chances of getting atheroma
    2. High Salt
  2. Bad Diet
    1. High Salt
    2. High in LDL
      1. Transports fats to your arteries, increases chances of atheroma
        HDL will take cholesterol and take it to you liver to be removed, so that's the good cholesterol
  3. Cigarette smoking
    1. Nicotine makes your blood cells thicker, increases chances of thrombosis
    2. Carbon monoxide will make the artery walls thicker and reduces the ability of the artery to dilate, restricted blood flow in the lumen

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	Created by bilkis-21 about 11 years ago