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Flashcards do conjunto (20)
- 1Describe and explain the adaptation of human lungs in relation to Fick's Law 5 MARKS-Short diffusion pathway (1)
-caused by thin squamous epithelial cells (1)
- large concentration gradient (1)
- caused by the constant removal of oxygen by the blood and constant renewal of oxygen by the alveoli (1)
-large surface area (1)
-caused by many small alveoli (1) - 2Describe the pathway of oxygen from an alveolus to the blood 3 MARKS- Diffuses (1)
-Through the alveolar epithelium (1)
- Into the blood via capillary endothelium (1) - 3Explain how ventilation maintains a concentration gradient 2 MARKS- Air high in oxygen is constantly entering the alveoli (1)
- Air low in oxygen is continuously being removed from the alveoli (1)
- Blood high in oxygen is constantly being removed - 4Describe and explain the process of inspiration 5 MARKS- Intercostal muscles contract (1)
- Therefore the ribs move up and out) (1)
- Diaphragm muscle contracts and diaphragm flattens
- Volume increases (1)
- Pressure increases relative to atmospheric pressure so air moves in (1) - 5Describe and explain the process of expiration 5 MARKS- The intercostal muscles relax (1)
- Therefore the ribs move down and in (1)
- The diaphragm muscle relaxes and the diaphragm returns to a dome shape (1)
- Volume decreases (1)
- Pressure increases relative to atmospheric pressure so air moves out (1) - 6Explain how paralysis of the diaphragm leads to breathing difficulties 2 MARKSDiaphragm will not flatten (1)
So lung volume will not increase (1) - 7Describe and explain the effects of pulmonary fibrosis 4 MARKS- Elastin may be destroyed so lungs no longer able to force air out of alveoli (1)
- A lack of ventilation means the concentration gradient cannot be maintained (1)
- Scar tissue (1)
- Increase length of diffusion pathway (1) - 8Explain why during an asthma attack less oxygen diffuses into the blood 2 MARKS- Airways restricted (1)
- Air in alveoli not replaced, so less oxygen (1)
- Concentration gradient not maintained (1)
- Rate of diffusion is lower (1) - 9Explanation of symptoms of asthma 4 MARKS- Difficulty breathing due to constricted bronchioles (1)
- Wheezing sound caused by air passing through restricted bronchioles (1)
- Tight feeling in chest, not being able to ventilate the chest adequately (1)
- Coughing, a reflex response to obstructed bronchioles (1) - 10Explain the effects of allergies on asthma 5 MARKS- Allergens cause white blood cells lining the bronchioles to release histamine (1)
- Lining of bronchioles becomes inflamed (1)
- Cells of epithelial lining secrete mucus (1)
- fluid leaves capillaries and enters airways (1)
- muscles surrounding bronchioles contract and constrict airways (1)
- Lack of ventilation means conc. gradient is not maintained (1) - 11Explain the effect of emphysema 4 MARKS- Elastin in the lung tissue has been permanently stretched (1)
- Lungs no longer able to force out air (1)
-Lack of ventilation means concentration gradient is not maintained (1)
- Surface area of alveoli is reduced and they sometimes burst (1)
- Diffusion of gases is less efficient (1) - 12Explain the symptoms of emphysema 3 MARKS- shortness of breath due to difficulty inhaling, due to loss of elasticity in the lungs (1)
- chronic cough due to body's effort to remove damaged tissue (1)
- bluish skin colouration due to low level of oxygen in blood as a result of poor gas exchange (1) - 13Describe the course of infection of TB 6 MARKS- bacteria grow in upper regions of lungs where there is a plentiful supply of oxygen (1)
- white blood cells accumulate at site of infection (1)
- leads to inflammation and enlargement of the lymph nodes (1)
-years later bacteria may re-emerge and cause a second infection (1)
- bacteria can destroy lung tissue, can result in cavities and scar tissue (1)
- sufferer can cough up damaged tissue with blood (1) - 14Explain the symptoms of pulmonary fibrosis 4 MARKS- shortness of breath due to a considerable volume of lungs being occupied by fibrous tissue (thickened epithelium - diffusion pathway increased )(1)
- chronic dry cough due to fibrous tissue obstructing the airways
- pain and discomfort in chest due to pressure and scarring due to coughing (1)
- weakness and fatigue due to reduced intake of oxygen in the blood (1) - 15What is Fick's Law? 1 MARKrate of diffusion =
surface area x conc. grad.
/ length of diffusion pathway
(1) - 16Calculate pulmonary ventilation 1 MARKPV = tidal volume x ventilation rate
- 17What is tidal volume ? 1 MARKThe volume of air taken in at each breath when resting in 0.5 dm3 (1)
- 18What is ventilation rate? 1 MARKThe number of breaths per minute (Exam tip - usually between 12 - 20) (1)
- 19What are the risk factors of lung disease? 5 MARKS- smoking (1)
- air pollution (1)
- genetics (1)
- infections (1)
- occupation (1) - 20Who may be more vulnerable to TB ? 5 MARKS- Young children (1)
- Elderly / patients (1)
- Pregnant women (1)
- People with HIV/AIDS (1)
- People undergoing chemotherapy (1)
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- Model Answers for exam questions for The Lung and Lung Disease Section
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