SBI242 Week 8 - Pharmacology of the Gastrointestinal Tract

All of the above

What are the primary functions of the gastrointestinal tract?

Myenteric plexus and Submucosal plexus

What are the two main nerve plexuses in the intrinsic nerve plexuses of the gastrointestinal tract?

D) Both b and c

What does the submucosal nerve plexus primarily regulate?

Muscular contractions and motility of the digestive tract

What does the myenteric nerve plexus primarily control?

Sympathetic: inhibits digestion; Parasympathetic: stimulates digestion

What are the effects of sympathetic and parasympathetic impulses on digestive activities?

Acetylcholine, nitric oxide, 5-hydroxytryptamine (5-HT, serotonin) and substance P

What are some neurotransmitters found in the enteric nervous system?

Carbohydrate digestion

What is the primary function of salivary alpha-amylase?

An antiseptic (e.g. alcohol, cetylpyridiniumchloride or chlorhexidine gluconate), an anaesthetic (e.g. benzocaine, lignocaine hydrochloride), an analgesic (e.g. choline salicylate) or an anticaries agent (sodium fluoride).

What is a common ingredient found in mouthwashes/gargles?

Providing temporary relief for dry mouth

What is the primary function of saliva substitutes?

Inhibiting viral DNA polymerase

How does aciclovir function in treating viral infections?

Binding to ergosterol in cell membrane, leading to the formation of pores or channels resulting in leakage of essential intracellular components

How does Nystatin treat fungal infections?

Inhibiting ergosterol synthesis, resulting in inhibition of fungal growth, interference in nutrient transport and death

How does Fluconazole treat fungal infections?

Secretion of pepsinogen, HCl, and mucus

What are the secretory functions of the stomach?

Secretion of Gastrin, Serotonin, Somatostatin

What is a key endocrine function of the stomach?

Hydrochloric acid (HCl) and Intrinsic factor

What do parietal (oxyntic) cells secrete?

Pepsinogen, gastric lipase

What do peptic (chief) cells secrete?

Facilitating vitamin B12 absorption

What is the primary function of intrinsic factor?

Initiation of hydrolysis of dietary proteins

What is the primary function of pepsin?

Initiation of hydrolysis of dietary lipids

What is the primary function of gastric lipase?

Heartburn

What is a common symptom of Gastro-oesophageal Reflux Disease (GORD)?

Mucosal damage → Inflammation → Neutrophil infiltration

What is the typical order of events in acute gastritis?

Urease and ammonia production

What is the buffering mechanism of Helicobacter pylori?

Motility, Ammonia production and adhesion, Toxins (local tissue damage)

What are some H. pylori virulence factors?

All of the above

What are some stimulants to gastric acid secretion?

D) A and B

What are some chemical inhibitors of acid secretion?

With gastric ulcers, the ability of the gastric mucosa to protect and repair itself seems to be defective; in duodenal ulcers, hypersecretion of acid and pepsin is responsible for the erosion of the duodenal mucosa

What is the difference between gastric and duodenal ulcers?

An increased mucosal permeability to hydrogen ions

What is the primary defect in gastric ulcer pathophysiology

A harder outer layer of tooth enamel that is more resistant to demineralization

What is the result of fluoride ions exchanging for hydroxyl or citrate (anion) ions?

Chemical compounds that buffer or neutralise hydrochloric acid in the stomach and thereby raise the gastric pH

What are antacids?

Enhance the protection afforded by the mucus layer or provide a physical barrier over the ulcerated surface

How do Cytoprotective Agents work?

Competitively block histamine from stimulating the H2 receptors located on the gastric parietal cells, reducing (~70%) gastric acid secretion, particularly nocturnal secretion

How do H2-Receptor Antagonists work?

Suppress gastric acid secretion by inhibiting the proton pump (H+, K+ ATPase enzyme system) at the secretory surface of the gastric parietal cells

How do Proton Pump Inhibitors work?

All of the above

What are some triple regimen combinations for antibiotic therapy for H. pylori-induced duodenal ulcers?

All of the above

Name the Sites and Mediators involved in Nausea and Vomiting

Blocking neurotransmitter receptors in the chemoreceptor trigger zone (CTZ)

How do antiemetics work?

Granisetron

What are NOT some dopamine antagonists used as anti-emetic drugs?

Metoclopramide

Which drug is NOT a 5-HT3-receptor antagonists used as an anti-emetic?

Fluconazole

What are NOT some NK1 (Neurokinin) receptor antagonists used as anti-emetic drugs?

All of the above

What are some causes of constipation?

All of the above

List some causes of diarrhoea:

Increasing water penetration into stool, softening it

How do fecal softeners work?

Increasing fibre content and water absorption, softening stool

How do bulk-forming (high-fibre) agents work?

Stimulating intestinal motility and secretion

How do Stimulants work to treat constipation?

Drawing water into the intestinal lumen, softening stool

How do Osmotics work as laxatives?

Coating and softening stool, facilitating passage

How do Lubricants/faecal softeners work as laxatives?

Decreasing gut motility

How do Opioid Anti-diarrhoeals work?

Infectious, immunologic (anticolon antibodies), dietary, genetic (supported by family studies and identical twin studies)

What are some suggested causes of Ulcerative Colitis?

All of the above

What is the Pathogenesis of Ulcerative Colitis?

Anaemia

What can result from malabsorption of vitamin B12 and folic acid due to involvement of the ileum in Crohn's Disease?

All of the above

What are some drug therapy options for Inflammatory Bowel Disease (IBD)?

Inhibition of prostaglandin synthesis and scavenging of reactive oxygen species

What is the MOA of Sulfasalazine?

Inhibition of dihydrofolate reductase (DHFR), reducing DNA synthesis

What is the MOA of Methotrexate?

Inhibition of purine synthesis, reducing lymphocyte proliferation

What is the MOA of Azathioprine (AZA)?

Inhibits mRNA responsible for interleukin-1 formation, producing anti-inflammatory, immunosuppressive and anti- mitogenic effects

What is the MOA of Prednisolone?

Inhibition of TNF-alpha

What is the MOA of Infliximab?

Hypoactive

A new drug is being tested that is known to inhibit parasympathetic
nervous system activity. It is expected that the salivary glands will
become:

Bilirubin

Analysis of a sample of normal bile would most likely reveal:

Carbohydrates

Salivary amylase (ptyalin) initiates the digestion of:

Parietal

The _____ cells of the gastric glands secrete hydrochloric acid.

Fluconazole

For severely immunocompromised patients with an oral fungal infection, which drug
would be most suitable?

Breaks in the mucosa and presence of corrosive secretions

A 54-year-old male is diagnosed with gastric ulcer disease. This condition is most likely
caused by:

Helicobacter pylori infection

The primary cause of duodenal ulcers is:

An inflammatory response to gastro-oesophageal reflux

Reflux oesophagitis is defined as:

Combine with other drugs and inhibit their absorption

Antacids - are chemical compounds that buffer or neutralise hydrochloric acid in the
stomach. Their main interaction with other drugs is that they:

Hypersecretion of acid by the stomach

The proton pump inhibitor can relieve the symptoms in patients with duodenal ulcer,
because there is:

Beta 2 agonist

Antiemetics act principally by blocking the neurotransmitters in the vomiting centre. Which of the following drugs is NOT an antiemetic drug?

Loperamide

Laxatives are used to treat constipation. Which of the following drugs do NOT treat constipation?

Ulcerative colitis

A 50-year-old male complains of abdominal pain, diarrhoea and stools with blood and
pus on the surface. A possible diagnosis would be:

Proton pump inhibitor

Drug therapy for IBD can include any of the following drugs EXCEPT:

Gastric ulcer

A 62-year-old complains about epigastric pain immediately after he starts to eat. This is
most likely due to: