Module 6a Flashcards
How many Australians have some form of lung disease?
1 in 10
What Australian population is 3x more likely to die of lung disease than any other?
Indigenous
What structures make up the upper airway?
Nasopharynx
Oropharynx
Laryngophaeynx
Larynx
What structures make up the lower airway?
Trachea
Bronchial tree
Alveoli
Lungs
What is the process of inspiration?
- Contraction (flattening) of the diaphragm that increases the size of the thoracic cavity. (Intercostal muscles assist in times of increase demand)
- The lungs expand increasing the anterior-posterior thorax dimensions
- Pressure drops enhancing pressure gradient
- Pressure drops enhancing pressure gradient
- Atmospheric pressure is now greater than intrapulmonary pressure and atmospheric air moves into the lungs.
What are the accessory breathing muscles?
- Sternocleidomastoid
- Scalene
- Pectoralis minor
- Serratus (inspiration)
- Abdominal muscles (expiration)
Define tidal volume (TV)
Air volume inspired in a normal breath (av. 500ml)
Define minute volume
Tidal Volume X respiratory rate over 1 minute
Define inspiratory reserve volume (IRS)
Maximum amount of air that can be forcibly inhaled in excess of normal inspiration (3000ml)
Expiratory reserve volume (ERV)
Maximum volume of air expired following a passive expiration (1100ml)
Define Residual Volume
Air remaining in lungs after forced expiration
Define Vital Capacity
Maximal amount of air expired following a maximal inspiration (4600ml)
Define total lung capacity
Volume in the lungs after maximal inspiration (5800ml)
What is ‘dead space’ in relation to the respiratory system?
Areas of the respiratory system that do not partake in gaseous exchange.
Anatomical - nasal passage, bronchi
Pathological - obstruction, collapse/disease of alveoli
What are the ventilation controls and what parts do they play?
Medulla Oblongata
- sets basic rate & rhythm
- fine coordination centre in Pons
Inspiratory Centre
- phrenic: supplies diaphragm
- intercostal: supplies intercostal muscles
Expiratory Centre (only in forced expiration) - usual expiration passive as inspiration stops -
What factors influence ventilation control?
- Drugs and medication
- CNS depression
- Stress and emotions
- Stretch receptors of the lungs
- Voluntary control - limited
What is the respiratory control cycle?
- Holds breath
- Increased Pco2 in blood and CSF
- Stimulates central chemoreceptors in medulla
- stimulates inspiratory muscles
- Increases respiratory rates
- Removes more CO2
- Decreased Pco2
- Decreased chemoreceptor stimulation
- Slow respirations
- Retain more CO2
What is pulmonary respiration?
The exchange of gases between the cells of the body and the outside environment is the essence of respiratory pathophysiology. Air must move freely in and out for this to occur.
What factors affect the pulmonary respiration?
- Structure and function of the chest wall
- Central nervous system control
- Acid-base balances
What is a V-Q mismatch?
A defect which occurs in the lungs whereby ventilation (the
exchange of air between the lungs and the environment) and perfusion (the
passage of blood through the lungs) are not evenly matched
What is a high VQ mismatch?
The patient has an adequate ventilation but reduced perfusion. This leads to ‘dead space’ where the ventilation is essentially wasted. E.g. A pulmonary embolism - Ventilation wont be effected however perfusion will be as blood wont be able to travel pass the clot.