Recent content by Smachine

I think its to do with DNA protection, as melanin is located at the top of nucleus in the keratinocytes. Europeans are normally exposed to less sunlights UV radiation so they normally don't need that much of it.

Hello! Ive been trying to understand mechanisms of blood pressure and so far the more I read the more confusing it gets. What I really don't understand is this - why does the pressure drop is largest in arterioles? The physiology book I use says that they constitute a high resistance and as...

To add on what's already been said, lymphocytes are found in the blood as already mentioned and there are many lymphoid organs that contain many lymphocytes (mostly B and T helper), like lymph nodes, spleen, tonsils, MALT (mucosa associated lymphoid tissue) which is mostly gastrointestinal...

Hi! I have heard this many times, even from quit educated people, that lack of calcium causes brittle nails. I know that nails contain protein - keratin, not calcium. And even if the body lacked calcium resorption from bones would first happen? So I don't see how it can cause brittle nails, but...

Epithelium that lines something like intestine means that its the last layer of cells in case of intestine facing the lumen. The villi are actually all covered with epithelial cells, this image of small intestine villi might help to see how they line them...

Im not sure which part of the mechanism are you not understanding, but the general idea is quit simple. ATP energy is spent to create concentration and possible also electrical gradient for one substance across cell membrane and the other substance is transported together with the first...

Actually there are really many applications of viruses, like gene therapy or using bacteriophage to treat some bacterial infections is another potential use. Also the RNA virus enzyme - reverse transcriptase is used a lot in molecular biology to get DNA version of RNA.

Glucose is a polar molecule so without any protein it cannot cross membrane. In case of intestine there is also an electrochemical gradient that drives the transport. There is less Na+ in intestine epithelial cells due to the presence of Na+/K+ pumps in basal cell membrane. Glucose is...

Thanks for replays guys. Yes, i know about voltage gated/ligand gated ion channels and Na+/K+ pump. And I understand how they work together to create both resting and action potentials. What I don't understand is how you can detect changes in membrane potential when those channels open and...

Hey, first post in this forum! Ive been reading a lot of books related to biology and the more I read the more confusing the subject of electricity in living organisms gets. For example, a lot of books introduce membrane potentials as something that can be measured using two microelectrodes...