Lungs and Lung Disease

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  • Created by: Steph
  • Created on: 05-01-13 12:35
During inspiration, do the intercostal muscles contract or relax?
Contract
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During expiration, what happens to the volume in the thorax and what happens to the air pressure?
The volume in the thorax decreases and the air pressure increases to above atmospheric pressure
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How are gases exchanged in the body?
Oxygen diffuses out of alveoli, across alveolar epithelium and capillary epithelium and into haemoglobin in blood. CO2 diffuses into alveoli from the blood and is breathed out.
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What is the structure of the gas exchange system?
Air is breathed in and enters the trachea. Trachea splits into two bronchi (one leading to each lung), each bronchus branches off into smaller tubes called bronchioles. Bronchioles end in small 'air sacs' called alveoli
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Inspiration is an active process. What does this mean?
It requires energy
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Name 3 adaptions of alveoli for gas exchange
1. Thin exchange surface (short diffusion pathway) 2. A large surface area (large number of alveoli) 3. Steep concentration gradient of O & CO2 between alveoli and capillaries (increases rate of diffusion. Maintained by flow of blood and ventilation)
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What happens to the diaphragm for it to change shape between inspiration and expiration?
The diaphragm muscles contract and the diaphragm moves down and flattens
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How does the diaphragm cause air to move into the lungs during inspiration?
It flattens and moves down, so the volume in thorax increases and there is a decrease in pressure to below atmospheric pressure. Air flows in from high to low pressure.
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What is the function of cilia?
To trap mucus and other particles and beat it down to the back of the buccal cavity where it is swallowed
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What is the tidal volume?
The volume of air inspired per breath when at rest
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What is residual volume?
The amount of air in the lungs that is contained after exercise, which cannot be expired
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How do you calculate pulmonary ventilation (minute ventilation rate)?
Tidal volume x number of breaths per minute
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Other than surface area, membrane thickness and steep concentration gradients, name 2 other features of the gas exchange surface
Very good blood supply, permeable membrane
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Name 5 ways to prevent Tuberculosis
Vaccination, good education about it, better housing, better healthcare, better nutrition.
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How is the tuberculosis bacterium transmitted?
In air droplets by choughing, sneezing and speaking
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What do the TB bacteria do to the body?
They destroy the lung tissue
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How does emphysema reduce the efficiency of gas exchange in the lungs?
Loss of elasticity of the lungs (damaged airways), thin walls of alveoli are broken down, this decreases the total surface area for gas exchange, meaning the rate of diffusion is slower
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What is the course of infection of TB?
Bacteria engulfed by phagocytes and encased in tubercle. They replicate and destroy epithelial cells if immune system is weak. Leads to fibrosis- less surface area so less diffusion. This damage allows bacteria to enter the blood
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Why may people who suffer from emphysema feel weak and tired?
Thin walls of alveoli have been broken down, so total surface area decreases. Less air breathed out because of loss of elasticity, less oxygen enters blood, less respiration and so less ATP produced
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What is the main cause of emphysema?
Continuous smoking (from teenage years until mid-40s)
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Other cards in this set

Card 2

Front

During expiration, what happens to the volume in the thorax and what happens to the air pressure?

Back

The volume in the thorax decreases and the air pressure increases to above atmospheric pressure

Card 3

Front

How are gases exchanged in the body?

Back

Preview of the front of card 3

Card 4

Front

What is the structure of the gas exchange system?

Back

Preview of the front of card 4

Card 5

Front

Inspiration is an active process. What does this mean?

Back

Preview of the front of card 5
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