Gastric and Intestinal Physiology Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which cell type in the gastric glands primarily secretes hydrochloric acid (HCl)?

Enteroendocrine cells

Mucous neck cells

Chief cells

Parietal cells (correct)

What is the main function of pepsin in the gastric juice?

To break down proteins (correct)

To digest carbohydrates

To activate HCl

To absorb Vitamin B12

Which of the following is NOT a symptom associated with dyspepsia according to the British Society of Gastroenterology?

Upper abdominal pain

Panic attacks (correct)

Heartburn

Nausea or vomiting

What protective mechanism does the gastric epithelium employ to prevent damage from gastric acid?

Tight junctions between epithelial cells Signup and view all the answers

Which of the following pharmacological treatments specifically reduces acid secretion in the stomach?

Proton pump inhibitors Signup and view all the answers

Which enzyme secreted in infants is responsible for breaking down casein, a milk protein?

Rennin Signup and view all the answers

What role does intrinsic factor play in the digestive system?

It is required for vitamin B12 absorption Signup and view all the answers

What is a potential side effect of motilin agonists on gastric function?

Increase gastric tone or inhibit gastric accommodation Signup and view all the answers

Which of the following conditions is indicated by new onset constipation in patients over 50 years of age?

Increased risk of malignancy Signup and view all the answers

What is the primary role of the large intestine?

To convert chyme into faeces for excretion Signup and view all the answers

What structure in the large intestine is responsible for the formation of haustra?

Tenia coli Signup and view all the answers

Which characteristic does the mucosa of the large intestine NOT have?

Presence of digestive enzymes Signup and view all the answers

What is the primary mechanism of action of omeprazole?

Covalent binding to cysteine residues on the H+/K+ ATPase pump Signup and view all the answers

Which of the following statements is true regarding the pharmacodynamics of omeprazole?

It can maintain an intragastric pH of ≥ 3 for 17 hours. Signup and view all the answers

What role do proton-pump inhibitors play in the treatment of gastric acid-related conditions?

They irreversibly inhibit the secretion of gastric acid. Signup and view all the answers

Which of the following is a property of omeprazole as a prodrug?

It gets converted to sulfenamide in the presence of acid. Signup and view all the answers

Which enzyme primarily metabolizes omeprazole?

CYP2C19 Signup and view all the answers

What is a notable characteristic of the efficacy of PPIs, including omeprazole?

Efficacy is closely linked to plasma concentrations. Signup and view all the answers

What is the pKa range for most proton-pump inhibitors?

3.8 to 5.0 Signup and view all the answers

Which type of therapy involves a proton-pump inhibitor and antibiotics?

Dual therapy Signup and view all the answers

What common clinical outcome might patients experience when using proton-pump inhibitors?

Observed treatment-related adverse events Signup and view all the answers

What is the primary mechanism of action for Metoclopramide in the gastrointestinal tract?

Acting as a dopamine D2 antagonist and serotonin agonist Signup and view all the answers

What differentiates Domperidone from Metoclopramide in terms of CNS effects?

Domperidone does not cross the blood-brain barrier Signup and view all the answers

Which drug is known to activate serotonin 5-HT4 receptors to release acetylcholine?

Cisapride Signup and view all the answers

What is a significant risk associated with the use of Cisapride?

Serious cardiac risks Signup and view all the answers

Which of the following statements best describes the action of Erythromycin in gastrointestinal treatment?

It enhances peristalsis by acting on motilin receptors Signup and view all the answers

What is the recommended use of Prucalopride in clinical practice?

Only in women with chronic constipation unresponsive to other treatments Signup and view all the answers

Which statement regarding the side effects of Metoclopramide is accurate?

Common side effects include drowsiness and restlessness Signup and view all the answers

What is the role of neurotransmitters like dopamine and serotonin in the gastrointestinal tract?

They enhance the motility of smooth muscle cells Signup and view all the answers

Which statement about the effect of atropine on certain gastrointestinal drugs is correct?

It blocks the action of serotonergic agonists Signup and view all the answers

Which of the following is not a common symptom of gastroparesis?

Diarrhea Signup and view all the answers

Which of the following is a potential iatrogenic cause of gastroparesis?

Vagal nerve damage during surgery Signup and view all the answers

What role do prokinetic agents play in gastrointestinal treatment?

Promote the passage of ingested material Signup and view all the answers

Which neurotransmitter is primarily stimulated by promotility agents to encourage smooth muscle contractions?

Acetylcholine Signup and view all the answers

Which condition is associated with gastroparesis due to its pathophysiological effects on the digestive system?

Hypothyroidism Signup and view all the answers

What are the potential side effects of non-selective drugs used as promotility agents?

Drowsiness Signup and view all the answers

Which of these treatment approaches for gastroparesis is generally recommended?

Dietary modifications Signup and view all the answers

In the context of gastroparesis, which gastrointestinal symptom is specifically related to delayed gastric emptying?

Bloating Signup and view all the answers

Which of the following statements about gastric emptying is accurate?

Gastroparesis involves delayed gastric emptying. Signup and view all the answers

What is a key consideration when using promotility agents for treating gastrointestinal disorders?

Simple stimulation of gut motility may not be valid. Signup and view all the answers

Study Notes

GI Conditions

Heartburn is a burning sensation in the chest, caused by stomach acid traveling up the throat (acid reflux). Chronic heartburn is called gastroesophageal reflux disease (GORD).
Dyspepsia/Indigestion involves irritation of the stomach lining (gastritis). Symptoms include pain, indigestion, and nausea.
Peptic ulcer disease is a condition where sores develop in the stomach lining.
Constipation and defecation problems involve difficulties with normal bowel movements.
Diarrhoea is frequent and loose bowel movements
Gastroparesis is a condition where the stomach cannot empty normally. Food moves through the stomach slower than usual due to nerve and muscle problems.
Nausea and Vomiting are common symptoms caused by several GI conditions or other factors.

GI Tract Layout and Stages of Dealing with Food

The alimentary canal extends from the mouth to the anus.
Accessory organs (liver and pancreas) assist in digestion.
The six stages of food processing are: ingestion, mechanical breakdown, propulsion, digestion, absorption, and defecation.

Saliva

Saliva is secreted by intrinsic or extrinsic glands.
Saliva components include amylase (enzyme), mucus, water, and protective elements (defensin, IgA, and lysozyme).

Swallowing Stages

Swallowing comprises buccal, pharyngo-oesophageal , and oesophageal phases, and involves sphincter openings.

Stomach Cell Types

Stomach cells include mucus cells, parietal cells, chief cells, and enteroendocrine cells.
Enteroendocrine cells secrete hormones to regulate digestion.

Regulation of Gastric Secretion

Gastric secretion has three phases: cephalic, gastric, and intestinal.

Digestive Processes (Stomach)

The stomach acts as a holding vessel, participating in mechanical and chemical digestion.
Proteins are digested with HCl activating pepsinogen to pepsin, which breaks down proteins.
Rennin breaks down casein (milk protein).
Intrinsic factor is necessary for vitamin B12 absorption.
The stomach lining is protected by a mucosal barrier from its own secretions.
The stomach lining is replaced every 3-6 days

Dyspepsia

Dyspepsia is a group of symptoms that indicate potential upper gastrointestinal (GI) tract disorders, not a diagnosis.
Key symptoms include upper abdominal pain, heartburn, gastric reflux, nausea, and vomiting.
Etiology (causes) encompass gastric and duodenal ulcers, gastroesophageal reflux disease (GORD), oesophagitis, and esophageal or gastric cancers.

Pharmacological Treatments for GI Issues

Mucosal strengtheners (e.g., misoprostol).
Acid reduction medications (e.g., proton pump inhibitors like omeprazole, Histamine H2 receptor antagonists, and Muscarinic antagonists).
Eradication of H.pylori (including PPI and antibiotic combinations).
PPI adverse effects and possible benefit subsets, and their implications for therapy, including plasma concentration.

Gastroparesis

Gastroparesis is the delayed emptying of the stomach and may be associated with several conditions such as diabetes, Hypothyroidism, neurological conditions such as Parkinson's disease, viral infections, and autoimmune attack.
Iatrogenic causes, such as vagal nerve damage during surgery, using medications like opioids, alpha-2-adrenergic agonists (e.g., clonidine), tricyclic antidepressants (e.g., amitriptyline), and anticholinergics (e.g., atropine), may also cause gastroparesis.
Treatment typically involves dietary adjustments and avoiding medications that delay gastric emptying.

Promotility Agents

Promotility agents are drugs that facilitate digestive tract movement.
Promotility agents act by stimulating or suppressing specific neurotransmitters in the GI, influencing movement.
Important considerations regarding efficacy and side effects are needed with regard to dosage.

Dopamine Antagonists (Metoclopramide and Domperidone)

Dopamine antagonists, like metoclopramide and domperidone, influence the central nervous system (CNS).
They either block dopamine D2 receptors or act on serotonin receptors.
These drugs stimulate peristalsis and increase gastric emptying.
Side effects include drowsiness.

Serotonergic Agonists

Serotonergic agonists such as cisapride and prucalopride are used to treat conditions like gastroesophageal reflux and gastroparesis.
These drugs act on serotonin receptors.

Motilides

Motilides, such as erythromycin (a macrolide antibiotic), have implications for gastrointestinal conditions like stasis.

Colon

The colon is part of the large intestine responsible for converting chyme to feces for excretion.
The colon lacks villi, unlike the small intestine.
Instead, it has crypts of Lieberkühn with goblet cells producing mucus.
The colon has specialized epithelial cells for absorbing nutrients and fluids.
Smooth muscles in the colon produce haustra, sacculated walls.

Secretion in the Colon

Mucus in the colon neutralises acidity, protects against irritation, and provides a binding medium for feces.
Defecation reflex triggers increased peristaltic motility and mucus secretion.
Bacterial infection contributes to watery / loose stools.

Absorption in the Large Intestines

The large intestine absorbs water, electrolytes, and some vitamins.

Control of Motility in the Colon

The mixing movement (haustrations) in the colon involves contractions of circular and longitudinal muscles, creating pockets called haustra.
Mass movements force feces along the colon.

Defecation

Stretch receptors in the rectum send signals to the spinal cord, triggering the defecation reflex.
The reflex involves relaxation of internal anal sphincter muscles, enabling the expulsion of feces.
Defecation may sometimes be hindered or triggered by external or cerebral influences.

Constipation

Constipation is characterized by infrequent or difficult bowel movements, with small, hard stools as a common symptom.
Underlying factors include poor diet leading to inadequate fibre intake; disorders like IBS; and medications (e.g., opioids).
Treatment options may involve bulk-forming agents, stimulant laxatives, osmotic laxatives, and stool softeners

Diarrhea

Diarrhoea involves 3 or more liquid stools in a 24 hour period
Two main types of diarrhoea – Inflammatory – caused by infection, immune response or chronic disease; and Non-inflammatory – caused by osmotic agents and secretory causes.
Management can include hydration and elimination of triggers/causes

Vomiting

Vomiting is a bodily function triggered by the vomiting reflex.
Multiple stages are involved – Pre-ejection, Retching, and Expulsive; and stimuli can be physical or chemical.

Anti-emetics

Anti-emetics are drugs used to treat nausea and vomiting.
Different antiemetics act on various receptors in the body (e.g., histamine H1 receptors, serotonin 5HT3 receptors, and dopamine D2 receptors.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the cellular and functional aspects of the gastrointestinal system, including the roles of gastric acids, enzymes, and protective mechanisms. This quiz covers important concepts related to digestion and gastrointestinal disorders.