Lung development, structure and gas movement Flashcards
What are the three tubular systems that are packed within the lungs called?
Airway
Pulmonary blood supply
Bronchial blood supply
Name the 5 stages during lung development
1) Embryonic
2) Pseudoglandular
3) Canalicular
4) Saccular
5) Alveolar
Describe the embryonic stage of lung development
- Formation of left and right lung lobes 26days-6weeks
- The primordial lung (lung anlage) develop as buds whihc extend outwards from the fetal foregut (oesophagus)
Describe the Pseudoglandular stage
- Formation of the gas conducting airway of the respiratory tree
- Fluid secretion into the airways creates a distending pressure that provides support for growth
What does Irregular dichotomous branching mean?
- Allows airways to fill spaces of varied dimensions which achieves even distribution of gas
- Allows distributuion of mechanical strain of breathing evenly
What gradient drives fluid movement into the airway lumen giving mechanical support for 3D growth?
Chloride gradient
Cl- is accumulated against its electrochemical gradient. Is there a higher number of Cl ions in the blood plasma or Airway lumen
Higher in blood plasma
Describe the canalicular stage?
Airways and blood vessels meet to form an interface. The blood-gas barrier
Describe the formation of the blood gas barrier
- Epithelial cells begin to differentiate
- Basement membrane forms
- Capillaries adhere beneath basement membrane
What type of cells are formed to make the barrier to capillary making the gas exchange surface?
Type I pneumocyte
Where does deoxygenated blood from the body return to?
The right atrium of the heart, contraction of the right atrium pushes blood tp the right ventricle, then sends blood through pulmonary artery to the lung
Why is the pulmonary artery called an artery?
Conducting blood from heart and sending to an organ
After the pulmonary artery brings the deoxygenated blood to the lung, what happens?
Lung oxygenates the blood and then returns to the left atrium along the pulmonary veins
Why is the pulmonary vein called a vein?
Conducting blood from an organ to the heart
What happens to the oxygenated blood in the left atrium?
Contraction of the left atrium pumps blood into the left ventricle which then contracts and circulates the blood around the body
The lining of the alveolar space is called what?
The pulmonary surfactant
What type of environment is the lung?
Sterile