Bio 5.2 Flashcards
What is air
a mixture of gases
Total pressure of a mixture of gases =?
= sum of the partial pressure of individual gases
How does gas move
moves from areas of high pressure to areas of low pressure
how is the volume and pressure of a gas related
inversely related
wha determines the amount of gas that will dissolve in a liquid
a. partial pressure of the gass
b. soluility of the gas in the liquid
what is the eqn for partial pressure of an atmospheric gas
= patm x % of the gas in atmosphere
wht is boyle’s law and what does it describe
pressure-volume relationphips are described by it
P1V1=P2V2
As volum increases
pressure decreases
why is pressure-volume relationship important (alveolar pressure)
talk about alveolar pressure
it is critical for ventilation
During inspiration and expiration, the volume of the thoracic cavity changes
- this causes changes in the alveolar pressure
- changes in the alveolar pressure are the driving force for air flow
How does the volume change in lungs
there are no muscles in the lung so they cant change volume on their own
the muscles are in the chest wall and will contract to change the thoracic volume
the lungs are passive elastic structures (like ballons)
What does volume depend on:
- the transpulmonary pressure - difference between alveolar presssure and intrapleural pressure
- the degree of elasticity of the lungs
what is the alveolar pressure
the pressure inside the lungs
what is the pressure in the intraplueral fluid
the pressure outside the lungs
How does air get in
oral cavity or nasal cavity
what is ventilation
the exchange of air betweeen the atmosphere and lungs
where and to what do the air need to be conditioned to before it reaches the lungs
Airways serve an importante role in conditioning the air
air needs to:
- Warm 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 foreighn materials
How does the airway condition the air ( Ck- form ECCF stuff and cila)
airways are lined with ciliated epithelia that secrete a watery saline solution
- cells move from Cl- form ECCF into the cell via the NKCC-Cl- transported to the lumen of airway via apical anion channels
- Na+ moves beweeen cells from ECF to lumen - gradient og NACL draws water towards the lumen creating the watery saline solution
Cilia are covered with mucus that is secreted by goblet cells
- mucus contains immune cells that kill invaders
- mucus is moved up to the pharynx (mucus escalator)
- transferred to the digestive tract where additional bacteria are destroyed.
What are the 2 steps of the respiratory cycle and in which do muscles conract
inspiration (contract) and expiration (dont contract)
Explain inspiration
activetransport
- Somatic motor nuerons trigger contraction of diaphragm and inspiratory muscles
- Thorax expands - thoracic volume is up
- Alveolar and intrapleural pressure decreases
- Lungs expand resulting in air flowing into lungs
Explain expiration
- Impulses from somatic motor neurons stop
- Diaphragm and thoracic muscles relax which returns thorax to their original position - volume down (elastic recoil)
- Alveolar and intrapleural pressure increases
- Elasticc recoil of the lungs decreases lung volume - air flows out of the lungs
when is expiration passsive and active
quiet breathing passive
active breathing- excercise or heavy breathing
Where is intraplueral pressure normally and when does int arise from
is normally sub-atmospheric and arises during feotal development
wha helps keep the lung expaneded and open
having lower pressure in the plueral fluid (outside the lung) than inside the lung (at rest)
What happens if air gets into the plueral cavity
intraplueral pressure increases
what happens if pressure difference is abolished what is it called and how could it be treated
the lung collapses, called pnuemothoraxm, and to treat apply suction to remove the air and seal the hole
the work required to breathe depends on two main factors:
- compliance (stretchability of the lungs
- the resistance to air flow in the airway
