Respiratory System Flashcards
(47 cards)
What are the main functions of the respiratory system
- Gas exchange between the environment and blood
- Control of the acidity of the body
- Filtering of the air inhaled
- Vocalisation
How many lobes are in each lung
Right - 3
Left - 2
What fills the thoracic cavity
Lung tissue (with the exception of the mid-sternal line where the heart, major vessels and oesophagus are)
What is the pleural sac
A double-walled enclosure of the lungs filled with fluid (pleural fluid)
What is the role of the pleural sac
Reduces friction from movement on the surface of the lungs
Fixes lungs firmly on the thoracic wall without any physical attachments
Role of rib cage and spine
Offer rigid protection to sensitive organs (heart and lungs)
Role of the muscles (diaphragm, intercostals and abdominals)
Support the rib cage and turn the chest into a pump that drives air flow
Functions of the airways
- Warming of inspired air
- Humidification of dry inspired air
- Filtration of inhaled foreign materials
What are the turbinates (conchae)
Bony dividers that increase the SA of the nasal cavity
What is the vestibule
The entrance to the nasal cavity that is the first line of airway defence
Small hairs and mucus in the vestibule help trap inhaled particles so they can be blown back out
What is Boyle’s law
P1 x V1 = P2 x V2
What is airflow directly proportional to
The pressure difference between two points
What is airflow inversely proportional to
The resistance that is created by the airways
What factors affect airway radius
Bronchodilation - CO2, epinephrine (via b2 receptors)
Bronchosriction - parasympathetic stimulation (via muscarinic receptor), histamine
What happens to the diaphragm during inspiration
It contracts
What happens to the diaphragm during expiration
It relaxes
What is the law of LaPlace
Pressure = (2xT(surface tension))/radius
What does surfactant contain
Proteins that disrupt the forces between water molecules, the result is a reduction in the surface tension of alveolar walls
What does reduced surface tension mean
- The alveolar spaces are less prone to collapsing
- The lung is more complaint and is inflated easier
What is spirometry
Spirometry is used to measure lung volumes but also to evaluate lung function by measuring variables such as the forced expired volume in one second (FEV1)
What measures cannot be measured using a spirometer
The functional residual capacity and residual volume
What is anatomical dead space
Refers to the part of the airways where gas exchange does not take place and is a fixed volume ~150ml
What is alveolar dead space
Refers to the areas of the lungs where gas exchange can take place but that are not properly perfumed with blood (eg, apex of upright lung)
What is minute ventilation
The amount of air that is moved by the lungs in one minute
