1- the few cholera bacterium which survive the stomach acid reach the small intestine
2- they use their flagella to propell them selves through the mucus lining of the intestine wall
3- they produce a toxic protein
This protein has 2 parts:
- one part binds to the carbohydrate receptors on the cell surface membrane. As only the epithilial cells have these specific receptors, this explains why the cholera toxin only effects this region of the body
- the other, toxic part, enters the epithilial cells. This causes the ion channels of the cell-surface membrane to open so that the chloride ions that are normally contained within the epithilial cells flood into the lumen of the intestine
4- the loss of chloride ions from the epithilial cells raises their water potential, while the increase of chloride ions in the lumen of the intenstine lowers its water potential. Water therefore flows from the cells into the lumen.