Boyle’s Law states that..
The pressure exerted by a gas is inversely proportional to the volume
Dalton’s Law states that…
the total pressure of a gas mixture is the sum of the pressures of each individual gas
Which way would a gas move?
From an area of high pressure to an area of low pressure
Charles Law states that…
The volume occupied by a gas is related to the absolute temperature
Henry’s Law states..
The amount of gas dissolved in a liquid is determined by the pressure of the gas & its solubility in liquid
What is the name of the cavity which contains pleural fluid?
Pleural cavity
Which membrane is in contact with the lungs?
Visceral pleura
Which membrane is in contact with the rib cage?
Parietal pleura
Name the different interfaces of the parietal pleura
Diaphragmatic (inferior)
Mediastinal
Costal
Cupular
What is the function of pleural fluid?
Lubricates pleural layers, reducing friction
Prevents membranes from separating
What is pleurisy?
Inflammation of the pleura
Intrapleural pressure is always positive or negative?
Negative- (subatmospheric pressure)
Which Law is the mechanics of breathing based upon?
Boyle’s Law - inc volume, decreased pressure allowing gases to move from high to low pressure.
What muscles are used in inspiration?
Diaphragm External intercostals (Scalene & sternocleidomastoid muscles)
What muscles are used in expiration?
At rest - passive (elastic recoil)
With inc respiratory load require internal intercostals & abdominal muscles
During inspiration, the diaphragm..
Contracts and moves inferiorly inc. thoracic volume.
During expiration, the diaphragm..
Relaxes and decreases thoracic volume, moving superiorly
Using inspiration, the external intercostals move the rib cage..
Upwards & outwards
The “bucket handle” motion alters the rib cage in which plane?
Medial/Laterally
On expiration, the internal intercostals move the rib cage…
Down & inwards
The “pump handle” moves the sternum in which plane?
anterior-posterior motion
What happens to the airways in asthma?
Overreactive constriction of bronchial smooth muscle, increasing resistance & difficulty of expiration.
Penetration of the thoracic cavity results in what medical condition?
Pneumothorax (collapsed lung) due to the disruption of the cohesive forces between pleural membranes. Loss of sub atmospheric intrapleural pressure.
Intra-thoracic (alveolar) pressure PA is positive or negative compared to atmospheric pressure?
It can be both
