Other Sensors With Pulmonary Implications – Control & Regulation of Breathing

00:00 Now, we need to discuss in a little bit more detail what some of those receptors were that give feedback besides chemoreceptors.

00:10 So one of the big ones were irritant receptors.

00:11 So these are located not only in the mouth, in the throat, and down some portions of the respiratory tract, that will sense things like dust, cold air, various chemicals.

00:24 But when they’re engaged, the big process that happens is you either cause coughing or bronchoconstriction.

00:31 So coughing would be to try to get that substance out of the lungs.

00:37 Bronchoconstriction would decrease the diameter of the bronchus.

00:41 In that way, you have less airflow travelling down it.

00:46 The joint and muscle receptors that are located in the various muscles, these help you to determine what the chest wall position is as well as the amount of muscular tension.

00:59 These usually will help give you feedback on the depth of breath and how hard the muscles are working.

01:06 When you look at stretch receptors, these are going to be in response to lung inflation.

01:12 And the important thing is to terminate inflation before you overinflate certain portions of the lung and damage them Finally, J receptors.

01:22 These particular ones are very interesting because they respond to both chemicals and stretch but I think even more importantly from a clinical perspective, they are responding for or responding during pulmonary edema.

01:36 So if a person has pulmonary edema, they are engaged just like if there was overstretching that happens or a chemical response.

01:47 This causes a shallow breathing such as this.

01:51 Bronchoconstriction, which decreases again the luminal diameter of the airway and increases the amount of mucus that is secreted into those particular airways.

02:03 So another problem with pulmonary edema is this effect with the J receptors.

02:08 So here’s an overall view of all the different receptors from irritant to stretch receptors to joint and muscle receptors to J receptors.

02:19 And I think you should have this question in your mind, is why in the world do you have all these particular receptors? I think the important thing to think about here is you want to protect the lungs and you want to protect what gets into the lungs because the lungs are very delicate.

02:34 There’s a very, very small diffusion distance and you can very easily get things or particles, bacterial or viruses across the lung membrane and cause infections.

02:47 The final clinical aspect that I’d like to discuss has to do with respiratory control.

02:55 There is something known as sleep apnea, which is becoming more prevalent in our population.

02:59 And in obstructive sleep apnea, here are two different diagrams.

03:03 One denotes airflow and the other is pleural pressure.

03:08 Pleural pressure is going to be the drive to breathe.

03:11 So as pleural pressure goes down, there should be airflow coming in, right? However, during obstructive sleep apnea, something blocks the airway so even though you’re trying to breathe in and you’re even breathing in more and more and more, you’re not getting any airflow.

03:29 And this is a very problematic condition in which you could cause a hypoxic and hypercapneic environment.

03:38 But we can compare and contrast obstructive sleep apnea to something known as central sleep apnea.

03:45 In central sleep apnea, you don’t have the drive to breathe.

03:49 There’s no problem with obstruction of the airways.

03:52 You simply stop that drive to want to breathe.

03:58 And this is also a dangerous condition which can cause both hypoxia as well as hypercapnea.

04:06 Comparing and contrasting centeral versus obstructive sleep apnea helps register in your mind the importance of the control and regulation of breathing versus simply blocking in an airway.

04:19 Showing both of these graphs here, looking at this obstructed airway versus this periodic cessation of airflow due to the lack of ventilatory drive.