Development of Respiratory System Flashcards
What is the lung composed of
netwrok of tubes that are intralaced with one another
How does the rate of branching intenisty change going towards the periphery
what about the size of the airways
increases
gets narrower and narrower
What does it supply
What do they conduct
pulmonary artery and veins
3 interlaced branch netwroks of tubes of which conducts gas to which blood pulmonary artery conducts enen though it shouldn’t conduct deoxiganted blood from the heart to the lung
what does the 5 stages of lung development achieve
blood gas barrier which is the interface between external envoirments the gas the blood takes that oxygen from the aulovei to your tissues and delivers carbon dioxide back to the lungs.
What is the emboynic stage of lung development
Formation of the left and right lung lobes
26 days to 6 weeks
the primordial lung develop as buds which extends outwards from the fetal foregut (oesophagus)
small long bud porturdes out is the foregut helping form that basic structure of the lung
What is the pseuogodlandular of lung dvelopment
Formation of the conduction airways of the respiratory tree
6 - 16 weeks
involves sequence of branching at different orders of magnitude for up to 21 generations
What other thngs happend during the second stage of lung development
fluid secretion into airways created distending pressure which gives mechanical support for the growth of the airways in 3 dimensions
airways and vasculture develop filling chest cavity
formation conduction airways and blood vessels
What is Irregular Dichotomous Branching
Lung is asymmetric and needs to fill an assymertic space
regular change in the dimensions of the branches but the position of the branches is irregular
why is irregular dichotmous branching important
achieves dipsersal of gas among terminal airways branches. mechanical strain dispered evenly among units
regulated increase in the number of airways at each branch disperes air flow resistance
what is in the pseuogodlandular lung
glandular airways
cappilriaes
column epitheulum
why is the pseuogodlandular open
these cells are creasitng fluids from the capillaries across the apathy into the airway lumen and provides the standing pressure
how is outstanding pressure to keep the lungs supported achieved in pseuogodlandular lungs
Chloride graident drives fluid movement into the airway lumen
Cl- accumaltes against electrochemical graident
Stages of giving support to the lungs
sodium enters and is pumped out by the K/NA pump
K enters by NKCC and leaves through baso lateral potassium channels
chloride is left inside the cell
acculamtes chloride so hyperpolarises
voltage activated CL- channels pulls CL- and sodium out the cell bringing water with it in the tight junctions brining fluid to the airway lumen
What is the Glandular stage of lung development
The formation of the blood gas barrier
dimater airway increases
decrease epitherical thickness
terminal bronchial form acini around where the alveoli will develop
myshcenichyme progress down the tree developing myoblasts fibroblasts and chondrocytes
