5.2 - Gas Laws and Ventilation Flashcards
What is the total pressure of a mixture of gases?
sum of partial pressure of individual gases
What factors determine the amount of gas dissolved in a liquid?
- partial pressure of the gas
- solubility of the gas in the liquid
How is partial pressure of an atmospheric gas calculated?
P X % of gas in atmosphere
atm
What does Boyle’s law explain?
The rs b/w volume and pressure
p1v1 = p2v2
What are the driving forces of air flow during ventilation?
alveolar pressure changes which are caused by changes of the thoracic cavity during inspiration and expiration
TRUE OR FALSE:
The lungs have their own muscles by which they can change volume
FALSE:
Lungs depend on muscles located in the chest wall
What is the structure of lungs?
passive elastic structures like balloons
What factors contribute to the volume of the lungs?
transpulmonary pressure
- difference between alveolar pressure intrapleural pressure
degree of elasticity of the lungs
What is the pressure inside and outside of the lungs?
inside: alveolar pressure
outside: pressure in the intrapleural fluid
What is the function of the airways?
- warm up air to 37 degrees celcius to maintain core body temp and protect alveoli
- add water vapour to air to prevent drying of epithelia
- filter out foreign material
What is the cellular process of filtering out foreign material?
- airways are lined with ciliated epithelia that secrete watery saline solution
- cells move Cl- from ECF into cell via NKCC
- Cl- transported to lumen of airway via apical anion channel
- Na+ moves between cells from ECF to lumen
- [] gradient of NaCl draws water towards the lumen creating the watery saline solution
What are cilia covered with?
covered with mucus
What secretes mucus and how is it secreted to the digestive tract?
goblet cells secrete muscus
mucus contains immune cells that kill invaders
mucus moved up to pharynx (mucus escalator)
transfered to disgestive tract where additional bacteria are destroyed
What are medical conditions that complicate ventilation?
cigarette smoking
- paralyzes cilia
- infections lead to smoker’s cough
cystic fibrosis
- inherited condition
- mutations in Cl- channel, not transported in lumen
- prevents appropriate secretion of water into the mucus
- thick and sticky in airways
- blocks airways
- prevents removal of bacteries = repeated infections
- over active immune cells start destroying lung
What are the steps of inspiration?
- somatic motor neuron trigger contraction of diaphragm and inspiratory muscles
- thorax expands, thoracic volume increases
- alveolar and intrapleural pressure decreases
- lungs expand resulting in air flowing into lungs