Page 153 - The Miracle in the Cell Membrane

Cells extending
along an air
cavity
Air cavity

Normal cells and the departure
of chloride ions

Air cavity

Defect in the cells and chloride ion departure of someone with cystic fibrosis.

The fatal disease of cystic fibrosis results in closure of airways in the lungs due to
an increase in fibrous connective tissue between cells. At the same time, this dis-
ease may also lead to blocked channels in the liver and pancreas. There is cur-
rently no cure. The researcher Paul Quinton determined that the cause of this dis-
ease is the faulty working of a protein in the cell membrane.

In healthy individuals, sodium ions enter the channel in the cell membrane by being
transported by the sodium-potassium pump. Chloride ions follow through a passive
channel. In cystic fibrosis sufferers, the potassium pump carries sodium ions into the
channel, but chloride ions cannot enter through the cell membrane. In other words, the
passive chloride channels do not function properly. (Sandra S. Gottfried, Biology
Today, Mosby-Year Book Inc., ABD, 1993, p. 70.)

As you have seen, a defect in just one passage through the cell membrane can have
fatal consequences. Countless conditions need to be met at the same time for you to
survive.

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