Respiratory System Function Flashcards
Function of RS
homeostasis of CO2 O2 and blood pH generation of speech warm humidify and clean air olfactory activated and deactivates some hormones heat exchange
until which generation of bronchi are there cartilage rings
5th
what is fick’s law of diffusion and how do our lungs’ structures ensure its adhered to for effectiveness
diffusion occurs more effectively with larger SA and a smaller diffusion distance
after 19th generation bronchioles’ diameter starts to remain the same, meanwhile the number of branches increases greatly - 300 million alveoli form surface are of 80-100m2 (inner surface area of lung is about 50 times larger than the outer)
diffusion distance between alveolus and pulmonary capillary is only 0.5 micrometers
what are cilia and mucous
mucous is the secretion of the mucous membrane that traps small particles, pollutants, smoke etc.
cilia are hair like structures on the membrane that move the particles up or down
where does the cilia beat (grow) upwards and where does it downwards
+ what size particles does each section of RS clean
down - nasal cavity (cleans particles larger than 10 micrometer)
up (mucous escalator) - large airways eg. larynx and trachea (5 to 10 micrometers)
respiratory bronchioles have alveolar macrophages instead of mucous and cilia (1 micrometer)
anything below this level is free floating (no structures to clean it) and its for particles under 0.5 micrometers
two types of walls within an alveolus
type I alveolar cells produces the membrane of the alveolus
type II alveolar cells produce the more inner membrane which produces alveolar fluid with surfactants
why are type II alveolar cells important
oxygen from alveoli can’t diffuse into capillaries in gas form
so these cells produce a alveolar fluid lining with pulmonary surfactant which allows the oxygen to dissolve in it, pass the outer membrane into the plasma and into the capillary along its partial pressure gradient
surfactant molecules also decrease water surface tension pressure
what is the law of Laplace
magnitude of inward directed pressure (P) in a bubble (alveolus) =
2 X Surface tension (T) / radius (r) of bubble (alveolus)
aka smaller the radius the larger the pressure
what supplies the surface tension of alveoli
the fluid (water) lining produced by type II alveolus cells
why is a pure water lining not ideal in the alveoli and what is our body’s solution
water tension would collapse the avioli
solution is surfactant molecules which are also produced by type II alveolus cells
these are mainly lipids and proteins dispensed between water molecules
since they have a different polarity, they reduce the attraction between the H2O molecules
these also reduce the water tension more in smaller avioli than in larger ones !!!
Overall surface tension with these surfactant molecules is called alveolar surface tension
three purposes of pulmonary surfactant molecules
educe lung’s renounce to recoil
increase pulmonary compliance
help maintain lung stability by preventing small avioli from collapsing into larger ones
