Lung Function 1.4 Flashcards
Outline exspiration.
The intercostal and diaphragm muscles relax, the ribcage moves downwards and inwards, the diaphragm becomes curved again. The thorax volume decreases, causing the air pressure to increase. Expiration is a passive process.
How are the alveoli adapted for gas exchange?
They have a thin exchange surface
Large surface area
Steep concentration gradient of oxygen and carbon dioxide between the alveoli and the capillaries.
What is pulmonary ventilation and how is it calculated?
PV is the volume of air taken into the lungs in one minute.
PV= tidal volume x ventilation rate
What is tidal volume?
The volume of air in each breath
What is Ventilation rate?
The number of breaths per minute.
Outline the transmission and course of infection for pulmonary turberculosis.
When someone becomes infected with TB, the immune system cells build a wall around the bacteria in the lungs, this forms small hard lumps, tubercles. Infected tissue within the tubercles dies, the gas exchange surface is damaged so tidal volume is decreased. TB is transmitted via droplet infection.
What are the symptoms of TB?
Persistent cough, coughing up blood or mucus.
Chest pains
Shortness of breath, fatigue
Fever
Outline the transmission and course of infection of fibrosis.
Fibrosis can be the result of pulmonary TB or exposure to substances like asbestos or dust. Fibrosis is the formation of scar tissue in the lungs. Scar tissue is thicker and less elastic than normal lung tissue. This means that the Lungs are less able to expand, so the tidal volume is reduced, there is also a reduction in the rate of gas exchange.
What are the symptoms of fibrosis?
Shortness of breath, dry cough
Chest pain
Fatigue and weakness
Outline inspiration.
The intercostal muscles and diaphragm contract, this causes the ribcage to move upwards and outwards, the diaphragm flattens. As the volume of the thorax increases the lung pressure decreases. Inspiration is an active process.
What is asthma?
Asthma is a respiratory condition where the airways become inflamed and irritated. The causes vary but it’s usually because of an allergic relation.
What happens during an asthma attack?
During an asthma attack, the smooth muscle lining the bronchioles contracts and a large amount of mucus Is produced. This causes constriction of the airways, making it difficult for a sufferer to breathe properly.
What are the symptoms of asthma?
Wheezing
A tight chest
Shortness of breath
What is emphysema?
It is a lung disease caused by smoking or long term exposure to air pollution- foreign particles In the smoke or air become trapped in the alveoli.
Describe the course of infection for emphysema?
The foreign particles in the alveoli causes inflammation, a which attracts phagocytes to the area. The phagocytes produce an enzyme that breaks down elastin, this also leads to the destruction of the alveoli walls which reduces surface area. The gas exchange decreases.
