Blood Supply and Lymphatic Drainage of the Pulmonary Lobule

00:00 this surfactant. Finally, I just want to mention a little bit about the blood supply.

00:05 There is a description on the right-hand side of this blood supply as we go through that you can read in your own time, but I just want to emphasize a couple of points. One is the pulmonary artery coming all the way down into the lungs accompanies the bronchi and the bronchioles, all the way down towards the respiratory bronchioles. This pulmonary artery remember, comes from the right ventricle carries deoxygenated blood. So all the blood passing into the capillaries is then oxygenated. It then forms into the pulmonary venules and finally the veins. Well the pulmonary vein leaves the lung along the outer components or the outer extremity of the lobule through the connective tissue septum between the lobules even though they are often very hard to find. So when you see a section through the lung and you see an air passage way, a bronchus or a bronchiole and the vessel next toward you can be pretty sure it is a component or a branch of the pulmonary artery. Whereas if you see a vessel on the outskirts on its own, not surrounded by the airway, then it is probably a pulmonary vein. And finally you can see in this diagram a lot of lymph vessels that drain fluid back from the lung alveoli and the interstitium I mentioned before, back, out of the lungs to return back to the vascular system. And then finally at the base you can see the pleura.

01:56 The pleura of the lung consists of two components, a mesothelial component, a visceral pleura against the lung to stop air from leaking into the thoracic cavity and then a pleurital pleura that forms a serous cavity in which the lungs will move during expiration and inspiration. So in summary then, it is important that you understand the structure and function of respiratory epithelium, that you understand the importance of chonchae in warming, moistening and cleaning the air. That you understand the structure and function of the olfactory epithelium and the components of the vocal cord or the larynx. And you recognize the importance of the epiglottis, that elastic flap that seals entry into the larynx and trachea when we swallow. And then it is also important you understand all the conducting passages into the lung, the difference between bronchus and bronchioles and respiratory bronchioles and then the importance of the different cell types that are at the interphase between the exchange of air and blood. And then finally just recall the difference in the blood supply, the difference in identifying pulmonary arteries and pulmonary veins if you look at a section through the lung.

03:21 Well thank you very much for listening. I now hope you have a very good knowledge of the histology of the respiratory system.