Cholera

Question 1

Cholera -

Answer 1

caused by bacteria called Vibrio cholerae

• usually killed by acidic conditions in the stomach
• few may survive, causing the disease

Question 2

How the bacteria causes diarrhoea and dehydration?

Answer 2

1) bacteria use their flagella to bury through the mucous lining of the intestine wall
2) release toxins that bind to glycoproteins and cause the ion channels to open
3) chloride ions leak into the lumen increasing the water potential of the epithelial cells
4) water moves out of the epithelial cells by osmosis
5) concentration gradient is established, chloride ions move into the epithelial cells from blood and surrounding tissues, water loss from blood and tissues by osmosis
6) severe diarrhoea and dehydration

+toxins cause loss of microvilli - decreased SA - less absorption - higher chances of dehydration and diarrhoea

Question 3

Oral rehydration therapy contains:

Answer 3

• water - to rehydrate tissues
• sodium - to replace the lost ions using the alternative sodium-glucose carrier proteins
• glucose - to stimulate the uptake of sodium ions and provide energy
• potassium - replace the lost ions and stimulate appetite
• electrolytes - to replace lost chloride and other ions