GIT

Question 1

Stimulus, mechanical and chemical properties of digestion

Answer 1

Stimulus: Acid and Enzymes are released
Mechanical: Churning or crushing of food
Chemical:
- Stomach acid to breakdown food particles and protect against food pathogens
- Enzyme such as pepsin breaks-down ingested protein into amino acids

Question 2

covers upper abdominal pain, fullness, early satiety, bloating and nausea. It can occur with gastric and duodenal ulceration

Answer 2

Dyspepsia

Question 3

is associated with heartburn, acid regurgitation and sometime difficulty in swallowing.

Answer 3

Gastro-oesophageal reflux disease

Question 4

chemicals associated with stomach acid secretion

Answer 4

Histamine (chemical mediator of allergic reactions such as airway obstruction) via H2 receptors
Acetylcholine (neurotransmitter responsible for autonomic response) via M3 receptors
Gastrin (peptide hormone responsible for enhancing gastric mucosal growth and motility in the stomach) via CCK1 receptors

Question 5

medications that inhibits the gateways of acid secretions

Answer 5

proton pump inhibitors

Question 6

proton pump inhibitors meds

Answer 6

omeprazole
pantoprazole
lanzoprazole

Question 7

MoA of PPIs or proton pump inhibitors

Answer 7

irreversibly inhibit the H+K+ ATPase or hydrogen potassium ATPase pump (an enzyme that acidifies the stomach) causing the reduction of acid production.

Question 8

PPIs adverse effects

Answer 8

risk of GI infection
vitamin B12 (responsible for making new RBCs) deficiency leading to pernicious anaemia
diarrhoea
headache
CAN CAUSE REBOUND GASTRITIS (since receptors were up-regulated enabling them to stimulate acids even more due to prolonged inhibition) is stopped after a long treatment

Question 9

Meds only blocks H2 receptors. prevents stimulation of acid secretion caused by histamine via H2 receptors

Answer 9

Histamine H2 receptor antagonists

Question 10

H2 receptor antagonist meds

Answer 10

Famotidine

Question 11

H2 receptor antagonist adverse effects

Answer 11

diarrhoea
headaches
rashes

Question 12

medication that does not work as proton pump inhibitor however, works with actual present acids in the stomach lumen neutralising it by releasing alkaline salts to buffer pH in the stomach. Usually prevents heartburn

Answer 12

Antacids

Question 13

Antacids meds

Answer 13

Alginates such as Gaviscon
Aluminium
Magnesium
Calcium carbonate

Question 14

Antacids adverse effects

Answer 14

Aluminium - constipation
Magnesium - diarrhoea

Question 15

as food moves through the colon, the ________ absorbs water from the food while it forms _____________. Muscle contraction in the colon then push the stool toward the _____________. Stool is solid by the time it reaches the rectum as most water was absorbed.

Answer 15

colon
stool
rectum

Question 16

occurs when the colon absorbs too much water, muscle contractions in the colon are too slow or sluggish which causes the stool to move slowly resulting to become dry and hard.

Answer 16

Constipation

Question 17

Common cause of constipation

Answer 17

dehydration
low fibre diet
immobility (weakened abdominal walls)
neurological disorders
refusal to open bowels

most susceptible to vulnerable groups such as disabled, older adults and pregnant women

Question 18

medications that causes constipation

Answer 18

opioids
Anticholinergics - TCAs, clozapine
Diuretics
Iron

Question 19

complications of constipation

Answer 19

haemorrhoids
anal fissures
bowel obstruction
rectal prolapse

Question 20

Bulk laxatives MoA

Answer 20

create bulk through addition of non-absorbable matter to faecal contents
it requires large intake of water since minimal osmotic action

Meds - psyllium

adv effects - decrease appetite

Question 21

faecal softeners MoA

Answer 21

acts as a surface detergent allowing fat and water to enter and soften the stool

meds - sodium docustate, poloxamer, sodium citrate (rectal)

Question 22

osmotic laxatives MoA

Answer 22

osmotic gradient for movement of water into the small or large intestines
increases bulk and soften faecal mass
promotes peristalsis (stretching of digestive tract)

meds - lactulose, magnesium, glycerol (rectal)

adv effects - abdominal cramps and flatulence

Question 23

stimulant laxatives MoA

Answer 23

direct stimulant of myenteric plexus (responsible for peristalsis of bowel movement)
increases peristalsis

meds - senna, bisacodyl (rectal)

adv effects - stomach cramps, dependency when long-term use

Question 24

occurs from overstimulation of muscle and nerves where there is less reabsorption of water in the body causing too much water in the stool

Answer 24

diarrhoea

Question 25

diarrhoea treatment

Answer 25

REHYDRATE
anti-motility agents - opioid agonists (loperamide and codeine phosphate)

Question 26

antidiahhroeal (loperamide) pharmacodynamics

Answer 26

binds to GI receptors to inhibit the release of acetylcholine via MU receptor > decrease peristalsis and increase transit time