so some cells of the epidermis is alive? if so how does it recieve oxygen? i know it can get some nutrients by diffusion, but how does it get oxygen if red blood cells can't diffuse leave the blood vessels?
...The epidermis is comprised of dead cells. It doesn't need blood vessels.
Capillaries are how they get oxygen. It allows 1cell through at a time.i guess my real question is how the cell groups without blood vessels recieve oxygen when red blood cells are too big to leak out of blood vessels, does hemoglobin or oxygen diffuse out?
*facepalm* Yes there is something of a mild oxygen diffusion gradient. It's a very low degree of diffusion because skin does not require a large amount of oxygen at all which is why you can place a tourniquet on a limb for several hours to a day and have no significant complications (and even when they do it's normally the muscles that are the source of the problem and not the skin). No hemoglobin does not "leak out" because they would require the erythrocytes (red blood cells) to rupture. This is called hemolysis and is a bad thing if it occurs with any regularity.i guess my real question is how the cell groups without blood vessels recieve oxygen when red blood cells are too big to leak out of blood vessels, does hemoglobin or oxygen diffuse out?
Actually, it doesn't "off-load into the plasma" of the blood. It offloads either into cells (JP or Veneficus can correct me if I am wrong but I believe it involves the cytochrome P450 enzyme or something like that....I hate cell biology). Now there is oxygen normally carried diffused in the plasma but it is a minority by a vast, vast percentage (see the bolded portion of the equation below for arterial oxygen concentration).Something not well covered in Basic class (or for that matter, some medic classes) is that O2 does not unload directly off of RBCs into the cell. It unloads off of RBCs into the plasma, and the into the cells. This is how diffusion occurs, and