Search found 32 matches
The answer to your question is yes. Normally, the b-b barrier cannot be passed by the immune cells. When infection occurs such as meningitis or encephalitis, because of the inflammation caused by bacterial toxins, destroyed neurons and endogenous substances, the endothelial cells become more permeab...
- Sat Jun 02, 2007 10:46 pm
- Forum: Physiology
- Topic: simple diffusion and skin cells
- Replies: 5
- Views: 10181
About 1% of respiration occurs through skin. This is an extremely low value if you take in consideration that the skin is almost always in contact with air and it has a very large surface. Skin is impermeable to water and solutes but liposoluble substances (including gases) can pass.
Other differences include blood composition : annelids have free hemoglobin in their blood, arthropods don't have any pigment in their blood since they have tracheal respiration and the others have hemocyanine as respiratory pigment (also circulating free in the blood).
- Mon Mar 05, 2007 5:11 pm
- Forum: Human Biology
- Topic: Antibodies in breast milk
- Replies: 16
- Views: 12577
Ph in the baby's stomach is higher than in the adult stomach (about 4.5-5 instead of the normal 1.5-3). Lower pH is needed for pepsin to be activated, so at a pH of 4.5-5 pepsin has little activity, so many proteins can escape digestion.
Well, in fact there are two different theories, one that states that mast cells are derived from basophyls and other that states that mast cells are derived from mastoblasts from the bone marrow (mastoblast->promast cell->mast cell)
Normally, some of the glucose passes away along with the glomerular ultrafiltrate in the proximal urinifer tubule . Then, all the glucose is actively reabsorbed so the final urine has no glucose. If the blood concentration of glucose is higher than a certain value (about 300 mg/dl but I'm not sure),...
Cancer cells have an altered cell cycle, having rapid division and lacking the mechanisms for apoptosys so we could say that they're immortal. Anyway, if an organism lives long enough, even without an ageing mechanism it will eventually die because of negative mutations. Mitochondrion DNA cannot be ...
The Marfan sindrome is caused by an autosomal dominant allele. The location of the defective gene seems to be the 15th chromosome. Being a dominant allele, it means that the child might be affected only if one of the parents has the disease (meaning that it has the gene). If one of the parents is mo...
A way for stopping an ion either from entering or from exiting a cell are voltage dependent channels (they open and close only at certain values of the cell potential). So equilibrum can't occur since at a certain voltage value the channel closes, even if the concentration gradients aren't met.
For #3: Usually equilibrum never occurs, since equilibrum is equivalent with maximum entropy (so maximum disorder), and organisms are ordoned systems. The gradients of concentration are maintained through active transport systems. For example, the gradient for Na and K is maintained by the Na/K pump...