q&a

the cardiovascular system is a complex beast.  there is an incredible amount of anatomy and even more physiology to learn before the system can be understood, even at a basic level.  so i have decided to focus a question on the small stuff.   which type of capillary is found in the lungs?

we learned about three kinds of capillaries:
1) continuous capillaries - found abundantly in the skin and muscles, uninterrupted lining, tight junctions
2) fenestrated capillaries - same as continuous but with oval pores, permeable to fluids
3) sinusoidal capillaries - leaky, allow large particles to pass

none of these sound like the kind of capillary that would be found in the lungs, exchanging carbon dioxide and oxygen.  i did some research on the respiratory system and learned the following.  pulmonary arteries branch into pulmonary capillary networks surrounding the alveoli which are air cells of the lungs where respiratory gases are exchanged.  so i haven't determined which type of capillary is found in the pulmonary capillary network, but i did learn that the gas is not exchanged directly from the capillary, rather it is exchanged from the alveoli, which is connected to lungs via the respiratory bronchiole.