Lungs and Disease
- Created by: Blackcurrant.
- Created on: 09-11-12 17:43
What structures do the lungs consist of?
Trachea, Cartilage Rings, Bronchi, Bronchioles, Alveoli, Internal/External Intercostal Muscles, Diaphragm
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What is the purpose of the human respiratory system?
Allows us to obtain the oxygen we need and get rid of carbon dioxide
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What is meant by ventilation?
Breathing - the movement of the ribs and diaphragm to allow air to move in and out of the lungs
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What happens during inhalation?
The external intercostal muscles contact moving the ribcage up and out, the diagphragm contracts and moves down which increases the volume of the thorax creatig a lower pressure inside the lungs than out, therefore causing air to move in
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What happens during exhalation?
The external intercostal muscles relax moving the ribcage down and in and the diaphragm relaxes and moves up decreasing the volume of the thorax so forcing air out of the lungs
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What is the function of the C-shaped cartilage rings?
To provide support for the trachea
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How are the lungs protected?
Tiny hairs in the nose, Cilliated cells and Goblet cells
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How do hairs in the nose protect the lungs?
Air is filtered by tiny hairs in the nose to remove dust and microbes before it reaches the lungs
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How do ciliated cells and goblet cells protect the lungs?
Goblet cells secrete mucus which traps dirt and microbes in the trachea, ciliated cells sweep the mucus up and out of the trachea into the mouth where it is swallowed and passed into the stomach where the microbes are killed by the acid there
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What is the purpose of the cough reflex?
To remove unwanted particles from the trachea
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Why does the cough reflex apply to smokers in particular?
Smoke paralyses ciliated cells so mucus isn't swept out of the lungs therefore there is often lots of unwated particles in the trachea which need to be removed
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What happens if dirt or microbes enter the alveoli?
White blood cells (Wandering Alveolar Macrophages) engulf them
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What are some properties of the alveoli?
Large suface area, One cell thick, Moist walls, Lots of capillaries, Lined with squamous epithelium, Maintain high concentration gradient, Fully permeable,
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Why do the alveoli have moist walls?
Carbon dioxide and oxygen dissolve in the liquid therefore diffuse quicker
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Why do the alveoli have thin walls?
So that there is a shorter diffusion pathway
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Why do the alveoli have squamous epithelium?
They are very thin so allow gases to diffuse across them easily
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Why do the alveoli have lots of capillaries?
So that there is a constant supply of red blood cells to maintain the concentration gradient, also reb blood cells have to slow down to squeeze through narrow capillaries which allows longer time for diffusion
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Why do gases have to diffuse across more than one layer of cells at the alveoli?
One cell thick capillary + One cell thick squamous epithelium = Two cells
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What are the main 4 types of lung disease?
Emphysema, Asthma, Pulmonary Tubercolosis, Pulmonary Fibrillation
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What is the cause of pulmonary tubercolosis?
The bacteria Mycobacterium tubercolosis or Mycobacterium bovis
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Why can TB lie dormant for many years?
The bacterium are protected by a thick waxy coat
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What are the symptoms of TB?
Persistent cough, Tiredness, Loss of apetite, Weightloss, Fever, Coughing up blood
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How is TB identified?
Cloudy lungs on an x-ray
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How is TB transmitted?
Water/droplet infection (can survive weeks after droplets dry out), Bovis version can be passed from cows to humans in milk
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What is the cause of primary infection with TB?
The bacteria are inhaled, they grow and divide in the lungs, WBCs accumulate at the site of infection causing inflammation therefore breathlessness
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When does primary infection of TB occur?
Usually in childhood
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What is meant by the post primary infection of TB?
After primary infection some dormant bacteria remain which re-emerge years later causing a second infection, destroying lung tissue which is coughed up
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How is TB controlled and prevented?
People are informed that they need to complete the course of antibiotics to get rid of all dormant bacteria, Vaccination, Improved health facilities, Better housing, Better nutrition, Pastuerisation of Milk
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What causes Pulmonary Fibrosis?
Scars on the epithelium lining of the lungs thickens the tissue so there is a longer diffusion pathway and a reduced rate of diffusion
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What are the symptoms of Pulmonary Fibrosis?
Breathlessness, Dry Cough, Chest Pains, Tiredness
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Why is breathlessness associated with Pulmonary Fibrosis?
The lungs lose their elastic recoil so the volume of air that they can hold is less so it is more difficult to inhale
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What is Pulmonary Fibrosis caused by?
Microscopic injuries to the lungs, genetics
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How is pulmonary fibrosis treated?
It cannot be treated as scarring is permanent - only option is a lungs transplant if very serious
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What is asthma?
A localised allergic reaction to dust, pollen, animal fur etc
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What is asthma triggered by?
Stress, exercise, anxiety, pollutants, cold air, infection
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Explain how asthma occurs.
Allergens cause WBCs in bronchioles to release histamines -->airway linings become inflammed -->epithelial cells secrete XS mucus, fluid leaves capillaries--> blocks airways. Muscles contract constricting airways making it hard to inhale
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What are the symptoms of asthma?
Breathlessness, Wheezing, Tight feeling in the chest, Coughing
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What are the symptoms of asthma due to?
Constriction of airways and being unable to properly ventilate the lungs
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How is asthma treated?
Bronchiodilators (steroids) which dilate the bronchioles, antihistemines taken everyday to reduce the effect of histemine secretion
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What is emphysema?
Enlarged avleoli so loss of elasticity
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What are the symptoms of emphysema?
Breathlessness, chronic cough, barrel shaped chest, bluish skin
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How is emphysema caused?
Smoking, factory fumes etc
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What are the treatments for emphysema?
No complete cures but Bronchiodilators help with breathlessness, Stop smoking
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What are the risk factors of emphysema?
Smoking, air pollution, occupation, genetic predisposition, infections
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What is spirometry?
Measuring lung capacity
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What is tidal volume?
The volume of air that moves in/out of the lungs during quiet/normal breathing
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What is vital capacity?
The maximum amount of air that moves in/out of the lungs when forced
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What is pulmonary ventilation?
The amount of air that moves in/out of the lungs per minute
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How do you calculate pulmonary ventilation?
tidal volume x ventilation rate (breaths per minute)
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How do you calculate the total lung capacity?
vital capacity + residual volume
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What is the inspiritory reserve volume?
The difference between the vital capacity and tidal volume
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Other cards in this set
Card 2
Front
What is the purpose of the human respiratory system?
Back
Allows us to obtain the oxygen we need and get rid of carbon dioxide
Card 3
Front
What is meant by ventilation?
Back
Card 4
Front
What happens during inhalation?
Back
Card 5
Front
What happens during exhalation?
Back
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