9)Atmospheric Pressure Flashcards
Earths atmosphere
The layers of glasses surrounding the earth
Main layers:
Stratosphere
Troposphere
Thermosphere
Troposphere
Contains More than 75% of the air
Contains all the water vapour
Height is 7-17km
Stratosphere
Contains ozone layer
Ozone arsorbs the harmful uv from the sun
Height is 80-100km
Thermosphere
Contains molecules ionised by solar radiation
Reflects radio waves
Height is 1000-13000
Composition of the atmosphere
78% nitrogen
21% oxygen
1% argon
Traces of water vapour and co2
Boltzmann distribution
N_h= N_0e^-mgh/KT
M= mass of one molecule T= temperature K= Boltzmann constant G=acceleration due to gravity N=conc of gas molecules
Due to the simultaneous effects of gravity, diffusion and atmospheric circulation
Atmospheric pressure
The weight of air column with the height of atmosphere and 1m^2 cross section
In pascals
Standard atmospheric pressure
b_0= 101325 pa
273 kelvin is temp
Sea level
45 latitude
Vibrations of atmospheric pressure with height
b_h=b_0e^ -h/ft
Effect of atmospheric pressure on the human body
Humans function at atmospheric pressure of 900-1050
Low oxygen levels lead to hypoxia
Oxygen deficiency
Effects of low atmospheric pressure
This means low pressure of oxygen
Insufficient oxygen for oxygenation of blood leads to hypoxic blood
100% at 0m
80% at 4000m
75% at 6000m
Effects of high atmospheric pressure
Results in oxygen deficiency because solubility of nitrogen in blood rises faster than solubility of oxygen
Baric chamber
Sealed chamber with wide range of controls of the air
Used for treatment of gas embolism
Investigation effects of low and high pressure on the body
Respiration
Process of talking up oxygen from air
Transport of oxygen to the cells within tissue
Transports waste co2 out the body
Lungs
Located in the chest
-elastic gas filled bags
Lungs are connected to the atmosphere by trachea and bronchi
Respiratory muscles
Main muscles:
Intercostal muscles
Diaphragm
Contraction of intercostal muscles expand the rib cage
Diaphragm contracts and flattens
The pleurae
The membrane that surrounds the lungs
The pressure inside the space between the 2 pleurae is lower than the atmospheric pressure
Lung ventilation
inhalation
On contraction of resp muscles
Volume of chest increases
Pressure in the pleural space drops below atmospheric pressure
Inner pleurae expands and increases volume of lungs
Air runs through trachea into lungs
Lung ventilation exhalation
Volume of chest is reduced
Pressure in pleural space increases above atmospheric pressure
Volume of lungs is reduced and air flows out
Alpha lecithin pulmonary surfactant
Reduces the surface tension of water and allows the lungs to expand
When missing the alveoli collapses and lungs can’t expand
Lung volume
Tidal volume
Amount of air breathed in or out during normal respiration
Inspiratory reserve volume
Additional air that can be inhaled after normal tidal breath
This is measured using a spirometer
Lung volumes 2
Exploratory reserve volume
The amount of air that can be breathed out after a tidal breath
Residual volume
The amount of air left in lungs after maximum exhalation
Artificial respiration
Positive pressure respiration
Negative pressure respiration
Positive pressure respiration
Trachea is connected to mechanical ventilator
Pumps fresh air into patients lungs
Pumps used air out of lungs
Negative pressure respirator
Pump withdraws air from the tank to produce negative pressure
Releasing pressure results in exhalation
Manual insufflation
Manually forcing air into patients lungs
Mouth to mouth
Mouth to nose
Mouth to mask
Mouth to nose and mouth
