Lung Function and lung disease
- Created by: Rachel98
- Created on: 18-05-15 15:23
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- Lung Function and Disease
- Lungs are specialised for gas exchange
- 1) Air enters the trachea when we breath in
- 2) The trachea splits into two bronchi. One bronchus leads to each lung
- 3) Each bronchus then branches off into bronchioles which are smaller tubes
- 4) The bronchioles end in alveoli which are small air sacs where gas exchange occurs.
- Ventilation is breathing in and out
- Inspiration
- 1) The diaphragm and the intercostal muscles contract
- 2) Causing the ribcage to move upwards and out while the diaphragm flattens. Increasing the volume of the thorax
- 3) As the thorax cavity volume increases, the lung pressure decreases to below atmospheric pressure
- 4) This cause air to flow into the lungs
- This is a active process: It requires energy
- Expiration
- 1) The diaphragm and intercostal muscles relax
- 2) The ribcage moves downwards and inwards while the diaphragm becomes curved again
- 3) The thorax volume decreases, causing air pressure in the lungs to increase above atmospheric pressure.
- 4) This causes air to be forced out of the lungs
- This is a passive process: It doesn't require energy
- Inspiration
- Alveoli are adapted for gas exchange
- A thin exchange surface - the alveolar epithelium is only one cell thick.
- Reducing diffusion distance
- Increasing rate of diffusion
- Large surface area - There are many alveoli which increase surface area for gas exchange to occur
- Increasing rate of diffusion
- Reducing diffusion distance
- Large surface area - There are many alveoli which increase surface area for gas exchange to occur
- Good transport system- there are many capillaries surrounding all of the alveoli
- Maintaining the concentration gradient of oxygen and carbon dioxide
- Increasing rate of diffusion
- Increasing rate of diffusion
- Maintaining the concentration gradient of oxygen and carbon dioxide
- A thin exchange surface - the alveolar epithelium is only one cell thick.
- Pulmonary Tuberculosis
- Infection
- 1) When a person is infected with the tuberculosis bacteria, the immune system cells build a wall around the bacteria in the lungs.
- Forming small, hard lumps called tubercules
- 2) Infected tissue within the tubercles dies.
- The gas exchange surface is damaged so tidal volume is decreased
- 3) Tuberculosis also causes fibrosis, further decreasing tidal volume
- 4) If the bacteria enter the bloodstream, they can spread to other parts of the body.
- 1) When a person is infected with the tuberculosis bacteria, the immune system cells build a wall around the bacteria in the lungs.
- Symptoms
- Persistent cough
- coughing up blood and mucus
- chest pains
- shortness of breath
- fatigue
- fever
- Many lose weight due to a loss of appetite
- Transmission
- Transmitted by droplet infection
- If an infected person sneezes or coughs, droplets of saliva and mucus containing bacteria are released
- If an uninfected person breaths in these droplets, the bacteria is passed on to them
- If an infected person sneezes or coughs, droplets of saliva and mucus containing bacteria are released
- TB tends to be more widespread in areas where hygiene levels are poor and where conditions are crowded
- TB can be prevented with the BCG vaccine and can be treated with antibiotics
- Transmitted by droplet infection
- Infection
- Fibrosis
- This is the formation of scar tissue in the lungs.
- It results from an infection or exposure to irritants such as dust and asbestos
- Scar tissue is thicker and less elastic than normal lung tissue
- SO the lungs are less able to expand meaning that they can't hold as much air as normal. the tidal volume is reduced
- It is also harder to force air out of the lungs.
- Rate of gas exchange is reduced due to a thicker exchange surface and a lower concentration gradient
- Both of these are factors which will reduce the rate of diffusion according to Fick's Law.
- Rate of gas exchange is reduced due to a thicker exchange surface and a lower concentration gradient
- It is also harder to force air out of the lungs.
- SO the lungs are less able to expand meaning that they can't hold as much air as normal. the tidal volume is reduced
- Symptoms
- shortness of breath
- dry cough
- chest pains
- fatigue/ weakness
- sufferers have a faster breathing rate than normal.
- This is to allow the to get enough oxygen to oxygenate their blood
- This is the formation of scar tissue in the lungs.
- Asthma
- a respiratory condition were the airways become inflamed and irritated.
- usually caused by an allergic reaction to dust or pollen
- During an attack the smooth muscle lining the bronchioles contract
- And a large amount of mucus is produced.
- This cause constriction of the airways making it difficult to breath
- Air flow into the lungs is severely reduced so less oxygen enters the blood
- Symptoms
- weezing
- tight chest
- shortness of breath
- Treatment
- Symptoms come on very suddenly during attacks and can be relived by drugs
- Usually an inhaler.
- Relaxes the muscles in the bronchioles to open up the airways
- Symptoms come on very suddenly during attacks and can be relived by drugs
- Relaxes the muscles in the bronchioles to open up the airways
- Symptoms
- Air flow into the lungs is severely reduced so less oxygen enters the blood
- During an attack the smooth muscle lining the bronchioles contract
- usually caused by an allergic reaction to dust or pollen
- a respiratory condition were the airways become inflamed and irritated.
- Emphysema
- A lung disease caused by long term exposure to irritants such as air pollen or smoking.
- Foreign particles in the air become trapped in the alveoli.
- This causes inflammation which attracts phagocytes to the area.
- The phagocytes then release an enzyme that digests the elastin in the walls of the alveoli
- This results in the loss of elasticity in the lungs.
- This means that the alveoli can't recoil and expel as well.
- It also leads to the break down of walls. Increasing the diffusion distance and decreasing surface area.
- Increasing rate of diffusion and reducing the efficiency of gas exchange.
- It also leads to the break down of walls. Increasing the diffusion distance and decreasing surface area.
- This means that the alveoli can't recoil and expel as well.
- Symptoms
- shortness of breath
- wheezing
- increased breathing rate in order to gain enough oxygen into the lungs to oxygenate the blood.
- This results in the loss of elasticity in the lungs.
- The phagocytes then release an enzyme that digests the elastin in the walls of the alveoli
- This causes inflammation which attracts phagocytes to the area.
- Foreign particles in the air become trapped in the alveoli.
- A lung disease caused by long term exposure to irritants such as air pollen or smoking.
- Lungs are specialised for gas exchange
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