13.2 Flashcards
(16 cards)
What are the 3 causes of diarrhoea? (3)
(1) damage to the epithelial cells in the intestine
(2) loss of microvilli due to toxins
(3) excessive secretion of water due to toxins
Why can diarrhoea be fatal? (3)
(1) excessive fluid is lost from the body
(2) and insufficient fluid is taken in to make up for this loss
(3) so dehydration results, which can be fatal
Why can’t you just drink water to treat diarrhoea and dehydration (that had resulted from cholera)? (2)
(1) Because water is not being absorbed from the intestine
(2) & the drinking of water doesn’t replace the electrolytes lost from the epithelial cells of the intestine
What 5 components should Oral Rehydration Solutions (ORS) contain? Explain what each ingredient does.
HINT : 1-2-2-2-1.
(5)
(1) water =
to rehydrate tissues
(2) sodium =
to replace lost sodium ions from the epithelium
& to use the alternative sodium-glucose carrier proteins
(3) glucose =
to stimulate the uptake of sodium ions from the intestine
& to provide energy
(4) potassium =
to replace lost potassium ions
& to stimulate appetite
(5) other electrolytes =
to help prevent electrolyte imbalance
What are the (not-so-health related) benefits of ORS? (3)
(1) they don’t require trained personnel
(2) they’re very accessible
(3) they can be given in large amounts without being harmed (can’t overdose)
When testing ORS samples to improve them, why must they ultimately be tested on humans? (2)
(1) Each species responds differently to the same drug
(2) because each species has different physical & chemical features
Suggest a reason why a placebo is necessary to ensure that the results of a drug trial are reliable (3)
(1) It acts as a control experiment
(2) Changes in the patients taking the real drug can be compared with patients taking the placebo,
(3) which ensures that results are due to the drug / not by chance
Suggest why the results of a double-blind trial may be more reliable than those of a trial in which the patients know whether they are taking the real drug or a placebo (2)
(1) There is no risk of any deliberate or accidental bias by the patients
(2) Those that know which drug they’re on might wrongly attribute changes in their symptoms to the drug
In error bars, if the standard deviation of the bars overlap, what does that indicate about the results? (1)
(1) results are due to chance or non-significant
In a study investigating the effectiveness of certain ORS samples, the control group was given standard ORS instead of pure water.
Suggest 1 ethical reason why. (1)
(1) Patients could become more ill / become worse / die
What are the 3 reasons rice starch should be used instead of glucose in ORS? (3)
(1) Because it’s a large & insoluble molecule that has no osmotic effect
(2) and it is readily available in many parts of the world
(3) and it has other nutrients such as amino acids, which help in the uptake of sodium ions
What’s the issue with using rice starch instead of glucose? (1)
How can this issue be fixed? (1)
(1) It produces a viscous solution so it may be hard to swallow
(2) They partly digest the starch with amylase beforehand
Why would an excess of sodium in ORS not be effective? (3)
(1) there would be excess Na+ in the lumen
(2) which increases the secretion of water
(3) diarrhoea worsens
Why would an excess of glucose and less sodium in the ORS not be effective? (3)
(1) more glucose = lower WP
(2) this increases the secretion of water
(3) dehydration = worse
Why would less glucose in the ORS not be effective? (1)
(1) less energy is released during respiration
If you need to take an ORS, you need to boil the water before mixing the powder in the water. Why? (1)
(1) to kill any diarrhoeal pathogens that make the patient’s condition worse
