A2 Respiratory system Flashcards
Name the organ responsible for gas exchange in humans
Lung
Where in the lungs does gas exchange take place?
Alveolus
Describe the pathway taken by air as it travels to the alveolus
Mouth/nose
Trachea
Bronchus
Bronchiole
Alveolus
Name structure A
Trachea
Which gas diffuses into the blood in the alveoli?
Oxygen
How is the alveolus adapted for its function?
Large surface area
Thin walls - one cell thick
Rich blood supply
Name structure B
Bronchus
Name structure C
Bronchiole
What is the function of the pulmonary surfactant
Lowers the surface tension and prevents alveolar collapse
Describe the process of inspiration
Diaphragm muscle contracts
Diaphragm moves downwards
External Intercoastal muscles contract
Rib cage moves out and up
Increases the volume of the thorax
Decreases the pressure in the thorax
Air moves into the lungs
Describe the process of expiration
Diaphragm relaxes
Diaphragm moves into a domed position
Intercostal muscles relax
Rib cage moves down and in
Volume of thorax decreases
Pressure in thorax increases
Air is forced out of the lungs
What is the function of the pleural membranes?
Surround the lungs and contain pleural fluid
What is the role of the cartilage rings in the trachea
Keeps the trachea open
What is the function of the cilia?
Waft the mucus upwards towards the top of the trachea
Name the cells that produce mucus in the respiratory system.
Goblet cells
What is the function of the mucus found in the respiratory system?
Sticky
Traps pathogen and particles in the air
How thick is the alveolus wall?
One cell thick
Reduces the diffusion pathway
What type of chemical is the pulmonary surfactant?
Phospholipid
How is a steep concentration gradient maintained at the gas exchange surface?
Lungs continuously ventilated
Ensure high concentration of oxygen in the alveolus
Blood containing very little oxygen is continuously delivered to the alveolus
Give the equation for pulmonary ventilation
Tidal volume x ventilation rate
What can spirometry be used to measure?
Amount of air exhaled n one second
Total volume of air that can be exhaled in one forced breath
Which lung diseases can spirometry be used to test for?
Asthma
Pulmonary fibrosis
Cystic fibrosis
COPD
How is a spirometry test carried out?
Explain the procedure to patient
Gain consent
Patient seals lips round mouth piece
Start with period of quiet breathing in and out
Take deep breath and then exhale as hard as possible for 6 seconds
Rapid inhalation and forced exhalation used to assess airway obstruction eg asthma COPD
Repeat results
What is the function of the pleural fluid?
Lubrication
Asthma causes difficulty in breathing. What happens in the respiratory system to cause this difficulty in breathing?
Inflammation of the bronchioles
Increases friction
Decreases volume of air in alveolus
Name the physiological test that can be used to diagnose/assess asthma
Peak flow
Spirometry
What are the symptoms of asthma?
Difficulty in breathing
Wheezing sound when breathing
Tight feeling in chest
Coughing
Describe in detail what happens in an asthma attack
Muscles in bronchiole wall contract
Constricts the diameter of the bronchiole.
Less air travels to the alveolus for gas exchange
How is asthma treated?
Bronchodilators - relax muscles in walls
Corticosteroid - reduce inflammation
What causes asthma?
Localised allergic reaction
Triggered by a variety of allergens
Give the cause of tuberculosis
Bacterial infection
Caused by Mycobacterium tuberculosis or Mycobacterium bovis
Give the symptoms of pulmonary fibrosis
Shortness of breath
Chronic dry cough
Pain in the chest
Weakness or fatigue
How is TB spread from person to person?
Air borne transmission
eg coughing sneezing
How does TB affect the lungs?
Infection causes inflammation
Tubercles formed
Scarring reduces elasticity of the lungs
Thickening of the epithelium
Give the symptoms of TB
Persistent productive cough
Tiredness
Loss of appetite
Fever
Coughing up blood
How is TB treated?
Antibiotic drugs
Vaccination
TB is more common in developing countries or poor living conditions. Why?
Lack of education for completing courses of drug treatment
Cramped living condition
Poor ventilation
Poor health facilities
Poor diet
Which respiratory disease causes the epithelium of the alveoli to thicken?
Pulmonary fibrosis
Which occupations can increase the incidence of pulmonary fibrosis?
Any job where particles are in the air
Asbestos fibres - builders
Coal dust - miners
Grain dust - farmers
Bird and animal droppings - farmer/zoo keeper
What is the biggest cause of emphysema?
Smoking
Give the symptoms of emphysema
Shortness of breath
Shallow rapid breathing
Chronic cough
Which lung disease results in a loss of surface area of alveoli?
Emphysema
Describe in detail how alveolus are destroyed in emphysema
Cigarette smoke stimulates white blood cells to release enzymes
Enzymes break down walls of alveoli
Loss of elasticity as elastin is broken down
Reduces ability of lungs to reoil
Air cannot be removed from the alveoli
What does peak flow measure?
Rate that air can be exhaled by a person
Give the units used in measuring peak flow
Litres per minute
What does a pulse oximeter measure?
Oxygen level (saturation) of blood
Give the normal adult score for peak flow
400-600 litres per minute
Describe how a peak flow test is carried out
Record patients height and age
Explain procedure and gain consent
Set pointer on peak flow meter to zero
Patient takes a deep breath and seal mouth round mouth piece
Keep meter horizontal
Breathe out as hard as possible
Take reading
Repeat
Use the highest volume gained
