The graph shows the relationship between gastrointestinal (GI) damage and gastric acidity in 37 healthy human volunteers.
[Source: Republished with permission of Elsevier Science and Technology Journals, from ‘Integrated gastric acidity can predict the prevention of naproxen-induced gastroduodenal pathology in normal subjects’, John Plachetka, Gaetano Morelli, Carolyn Hines, Julie Borland, Alison Lyke, Diane Littlefield, Jerry D. Gardner Gastroenterology, Vol. 124, Issue 4, 2003; permission conveyed through Copyright Clearance Center, Inc.]
State the relationship between gastric acidity and GI damage.
GI damage can include ulcers. Outline the treatment of stomach ulcers.
Other than gastric acidity, state a primary cause of stomach ulcers.
probability of GI damage increases with increased «gastric» acidity
Do not accept “directly proportional”
a. proton pump inhibitors reduce stomach acid «production»
b. antacid/medication to neutralize/decrease acidity
c. «lower acidity» allow GI damage/ulcers to heal
d. antibiotics for H. pylori/bacterial infection
e. diet/lifestyle changes/eliminate smoking/alcohol
f. surgery needed with extensive gastric damage
Accept “cauterization” for marking point f
[Max 3 Marks]
a. Helicobacter pylori/H. pylori «infection»
b. use of non-steroidal anti-inflammatory drugs/NSAID/aspirin/ibuprofen
Accept valid examples of NSAID but do not accept trade names
[Max 1 Mark]
The diagram shows a cell in the lining of the stomach.
Outline the importance of the proton pumps in the digestion of foods.
Explain the use of proton pump inhibitors to treat patients complaining of stomach pain.
a. pumps protons/H+ into the stomach
b. allows for the production of «hydrochloric» acid
c. «hydrochloric» acid accelerates digestion/activates enzymes
d. gives optimal pH for pepsin/enzyme digestion
a. proton pump is a «transmembrane» protein
b. proton pump inhibitors bind to the proton pump
c. hydrogen ions are not sent into stomach lumen
reduction of «gastric» acid production
d. increase in pH of stomach
e. relieve symptoms of acid reflux/gastritis/ulcers
State two roles of hydrochloric acid in gastric juice.
Pancreatic juice is secreted into the pancreatic duct which carries these secretions to the small intestine.
The hormone secretin is released by the small intestine when hydrochloric acid enters it from the stomach. The data below show the volume of pancreatic juice released after an injection of secretin.
Pancreatic secretions contain sodium hydrogen carbonate, making them basic.
Deduce the significance of the response by the pancreas to secretin.
State one cause of stomach ulcers.
a. activation of enzymes/protease/pepsinogen
b. bactericidal action / kills pathogens
c. hydrolysis / breakdown of food
a. secretin stimulates an increase in pancreatic secretions
b. pancreatic secretions are released rapidly / within 10 minutes
c. «NaHCO3 in pancreatic secretions» neutralises stomach acid / HCI
d. provides optimal conditions for digestion / enzymes «in the small intestine»
e. by 40 minutes no more hydrochloric acid enters the small intestine
an infection by Helicobacter pylori / H. pylori
overuse of NSAIDs /aspirin / ibuprofen
Outline the importance of acid conditions in the stomach.
Suggest one reason for a correlation between a low-fibre diet and a higher incidence of gastrointestinal problems.
Acidity activates digestive enzyme «pepsinogen»
Hydrolysis/breakdown of food
Acidity destroys unwanted bacteria/pathogens
Provides optimum pH for enzymes/pepsin to function
Increased contact time between intestinal wall and food
Increase interaction with surface and undesirable food chemicals
The density/hardness of the stool can make it harder to egest causing damage to tissues
Increases digestive tract conditions/diseases/constipation
Elderly people lose bone mineral density (BMD) with age, and this is the source of many health issues, including higher risk of bone fractures. Researchers measured the change in BMD amongst elderly men considering many factors, over a period of four years. The results presented below show the difference between bone density change due solely to vitamin C intake and bone density loss considering a combination of the other factors represented by the baseline (zero). BMD was measured in the spine and at two femur (thigh bone) locations (femoral neck and trochanter) using scanner images. Daily intake of total vitamin C was categorized as high, medium or low.
Outline the effect of vitamin C intake on changes in bone density in the spine.
Compare the changes in bone density of the femoral neck with those of the spine.
Evaluate the evidence provided by the data that the intake of vitamin C supplements may reduce bone density loss in elderly people.
a. high (vitamin C) causes a positive change (in BMD) whereas medium/low causes negative change;
b. inversely proportional (for relative change);
c. if vitamin C intake increases, BMD increases;
a. positive change/reduced loss for femoral neck at all levels whereas only at high intake for spine;
b. higher values for femoral neck for each intake category;
c. inversely proportional for both;
d. no overlap between range/standard deviation / clear distinction of protective effect between femoral neck and spine (for high/all intake categories);
a. high intake results in positive value (for all locations);
b. protective effect proportional to intake;
c. proportion of vitamin C intake from supplements / influence of other factors not stated;
d. only a few bone locations measured / sample size unknown / high medium and low not defined;
At least one implication and one limitation required.
Outline the importance of fibre as a component of a balanced diet.
Distinguish between minerals and vitamins.
fibre/cellulose cannot be digested;
aids peristalsis/helps to prevent constipation/adds bulk;
prevents obesity by increasing bulk in the stomach;
reduces the risk of appendicitis/cancer/hemorrhoids;
slows the rate of sugar absorption/helps prevent diabetes;
minerals are inorganic elements (simple compounds from elements in ionic form) and vitamins are organic compounds (which cannot be synthesised by the body);
minerals are all water soluble but only some vitamins are water soluble (others are lipid soluble);
some vitamins are destroyed by exposure to oxygen, minerals are not;
List two possible variants in the molecular structure of unsaturated fatty acids.
State one reason to include fibre in the diet.
Describe the health consequences of a diet rich in proteins.
number of carbons (in the chain/length of chain);
number of double bonds (in the chain) / may be monounsaturated/ polyunsaturated;
cis/trans structure in unsaturated fatty acids / OWTTE;
location of double bonds;
counting inwards from opposite end of COOH group/omega 3/omega 7;
(bulk) may help regulate digestive process/peristalsis/prevent constipation;
may lower risk of colon/intestinal cancer/appendicitis/diabetes/cardiovascular disease;
may decrease hunger (helping with control of food intake);
quick drop in weight (through loss of body fluids);
important for children/pregnant/breastfeeding women;
loss of calcium ions in urine / possible risk of osteoporosis;
unbalanced diet / lack of essential nutrients;
e.g. essential vitamins/minerals/fibre;
possible rise in blood pressure;
release of ketones into bloodstream/ketosis (causing loss of appetite);
possible risk of kidney/liver disorders/stones/reduced functioning;