Respiratory 3 Flashcards
What are Alveoli?
Tiny, thin-walled capillary ruch sacs in the lungs where the exchange of oxygen and carbon dioxide takes place
What is the netting around alveoli made of?
Blood vessels
When does the amount of blood in capillaries increase?
During physical activity
What are the two types of Alveolar cells?
Type I and Type II
What kind of alveolar cells are the walls of Alveoli made of?
Type I alveolar cells
What are the characteristics of Type I alveolar cells?
- Continuous monolayer of flat epithelial cells
- Cell do not divide
- Susceptible to inhaled or aspirated toxins
How many of each type of alveolar cells are there?
There are way more type I alveolar cells than type II alveolar cells
What do Type II alveolar cells do?
- Produce surfactant
* Act as progenitor cells
What is surfactant produced by Type II alveolar cells?
A detergent like substance made of lipoproteins that reduces the surface tension of alveolar fluid
What occurs when there is injury to type I cells?
Type II cells can multiply and eventually differentiate into Type I cells
How wide is the blood vessels in alveoli?
They are just wide enough for one blood cell to pass
How long does each RBC spen in the capillary?
0.75 seconds and travers 2 or 3 alveoli
What must O2 and CO2 go through for gas exchange in the alveoli?
The respiratory membrane
What makes up the respiratory membrane?
- Surfactant
- Epithelial cells
- Basement membrane
- Interstitial space
- Basement membrane of capillary
- Capillary epithelium
Why is the thickness (it’s very thin) of the respiratory epithelium a problem?
Because it can be easily damaged by high blood pressure causing plasma and RBCs to go into the lungs
