Internal Respiration (Nursing)

00:01 So now that we talked about external respiration, let's switch gears and talk about internal respiration, which is going to be the gas exchange between our blood capillaries and our body's tissues.

00:16 This is also going to be affected by partial pressures and diffusion gradients except this time instead of with external respiration where oxygen is going in and carbon dioxide is going out.

00:28 We're going to switch it.

00:30 And oxygen is going to be going out into the tissues and carbon dioxide is going to be going into the blood so that it can be returned to the alveoli.

00:40 This happens because the partial pressure of oxygen in our tissues is lower than that of arterial blood.

00:48 Recall the partial pressure of oxygen and tissue is about 40, whereas in arterial blood the partial pressure is about a hundred.

00:57 So the oxygen is going to move out of the blood and into the tissue down its diffusion gradient.

01:05 The tissue partial pressure of carbon dioxide on the other hand is higher than that of arterial blood.

01:12 Remember our partial pressure of carbon dioxide in our tissues is 45 compared to 40 in our arterial blood.

01:21 So the carbon dioxide is going to move down its concentration gradient out of the tissues and into the blood.

01:28 From there, the veins are going to return that blood to the heart and eventually to the lungs so that we can now go through this process of external respiration again, and then we start the cycle all over again.