21 MAY 2013 by ideonexus

 Different Cells are Replaced at Different Rates

Different types of cells have different lifespans, e.g.:  we shed our skin cells about every 35 days red blood cells live about 120 days, platelets 6 days and white cells less than a day most of the adult skeleton is replaced about every 10 years the average age of a fat cell seems to be about 10 years a 25-year-old heart replaces about 1% of all its cardiomyocytes (heart muscle cells ) over the course of a year, while a 75-year-old heart replaces about half a percent ...
Folksonomies: biology physiology
Folksonomies: biology physiology
 1   notes

Neural cells are not replaced at all.

03 MAY 2011 by ideonexus

 The Immune System VS Viruses

The immune system consists of white blood cells that come in about 10 million different types. Each type has a protein lock on it called an "antibody," which corresponds to a key carried by a bacterium called an "antigen." If a key enters that lock, the white cell starts multiplying ferociously in order to produce an army of white cells to gobble up the key-carrying invader, be it a flu virus, a tuberculosis bacterium, or even the cells of a transplanted heart. But the body has a problem. It ...
  1  notes

An excellent description of the battle going on inside our bodies.