Gastrointestinal Disorders Quiz

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Questions and Answers

What is the primary cause of peptic ulcers as mentioned?

Low pH in the stomach

Bacterial infection only

Food allergies

Increased gastric secretion (correct)

Which conditions are associated with increased gastric acid secretion leading to duodenal ulcers?

Hyperparathyroidism (correct)

Asthma

Chronic fatigue syndrome

Itchy skin disorders

What mechanism allows the stomach to accommodate a large volume of food without significantly increasing intragastric pressure?

Sphincter relaxation only

Receptive relaxation and plasticity of the gastric wall (correct)

Inhibition of nerve signals

Increase in gastric acid production

What physiological law relates tension in a hollow viscus to distending pressure?

Law of LaPlace Signup and view all the answers

Which of the following factors decreases the spike potential rate in the stomach?

Secretin Signup and view all the answers

Which symptom is commonly associated with gastric ulcers according to the provided content?

Weight loss Signup and view all the answers

Where does peristalsis in the stomach primarily originate?

Midpoint of greater curvature Signup and view all the answers

Which condition is NOT associated with the formation of peptic ulcers?

Low dietary fiber intake Signup and view all the answers

What role does the pelvic nerve play in the defecation process?

Contraction of the rectal wall and relaxation of the internal anal sphincter Signup and view all the answers

Which part of the nervous system is primarily involved in inhibiting the defecation reflex under unsuitable conditions?

Sympathetic nervous system Signup and view all the answers

Which factor is NOT a cause of constipation?

Chronic use of diarrhea-inducing medications Signup and view all the answers

What physiological process assists in the act of defecation by increasing intra-abdominal pressure?

Straining against a closed glottis Signup and view all the answers

What is a characteristic feature of spastic colon associated with anxiety?

Alternating constipation and diarrhea Signup and view all the answers

What is the primary mechanism through which the pudendal nerve contributes to defecation?

Relaxing the external anal sphincter Signup and view all the answers

In the context of defecation, when the rectum fills to 25% of its capacity, what response is triggered?

An urge to defecate is initiated Signup and view all the answers

What physiological effect occurs during forced expiration against a closed glottis?

Increased abdominal pressure Signup and view all the answers

What is the primary nature of peristaltic movements?

Neurogenic regulation Signup and view all the answers

Which hormone is NOT known to enhance intestinal motility?

Secretin Signup and view all the answers

Which type of peristalsis is characterized by strong contractions in response to irritation of the intestinal mucosa?

Peristaltic rush Signup and view all the answers

What is the rate of the basic electrical rhythm (BER) initiated by the interstitial cells of Cajal in the duodenum?

12 per minute Signup and view all the answers

What is one role of the ileocecal sphincter in intestinal motility?

It prevents reflux of cecal contents into the colon. Signup and view all the answers

Which nervous influence is responsible for increasing intestinal motility?

Vagus nerve stimulation Signup and view all the answers

Which neurotransmitters are associated with the contraction of longitudinal muscle during peristalsis?

Acetylcholine and Substance P Signup and view all the answers

What is the typical propagation speed of peristaltic movements in the intestine?

1-5 cm/second Signup and view all the answers

What is the primary function of lipoproteins in tissues?

Split and oxidize fats or store them Signup and view all the answers

Which vitamins are stored by the liver?

A, D, E, K, B12 Signup and view all the answers

How does the liver respond to increased blood iron levels?

Stores excess iron in the form of ferritin Signup and view all the answers

Which clotting factors require vitamin K for their synthesis?

II, VII, IX, X Signup and view all the answers

What is the purpose of the storage function of the liver during severe hemorrhage?

To release stored blood into the circulation Signup and view all the answers

Which of the following functions is NOT attributed to the liver?

Fatty acid oxidation exclusively Signup and view all the answers

What is formed by the liver involved in erythropoiesis?

Hemoglobin globin fraction Signup and view all the answers

What stimulates the contraction of the gall bladder during meal times?

Cholecystokinin hormone Signup and view all the answers

What mechanism primarily leads to increased hemobilirubin in the bloodstream during hemolytic jaundice?

Increased rate of RBC hemolysis surpassing hepatic uptake capacity Signup and view all the answers

Which condition is NOT classified under hepatic jaundice?

Obstruction of the bile duct by a tumor Signup and view all the answers

What is a consequence of decreased hepatic cell uptake of hemobilirubin?

Elevation of alkaline phosphates and bile salts in blood Signup and view all the answers

Which of the following explains the back diffusion of cholebilirubin into the bloodstream?

Obstruction of bile canaliculi due to inflammation Signup and view all the answers

Which condition can result from excessive RBC hemolysis?

Hemolytic anemia Signup and view all the answers

What is a likely outcome when there is obstruction of the bile duct?

Increased levels of cholebilirubin in the blood Signup and view all the answers

What is the primary factor leading to cholecystitis?

Obstruction of bile ducts by gallstones Signup and view all the answers

What role do drugs play in the development of hepatic jaundice?

They may cause direct damage to hepatocytes impacting bilirubin metabolism. Signup and view all the answers

Study Notes

Peptic Ulcer

Erosion of mucosal membrane in the gastrointestinal tract (GIT) caused by increased gastric secretion or disruption of the mucosal barrier.
Common risk factors include stress, depression, anxiety, gastrin-secreting tumors, excessive aspirin, alcohol, smoking, and Helicobacter pylori infection.
Frequent sites: prepyloric portion of the stomach, proximal duodenum, lower esophagus, and rare in jejunum.
Duodenal ulcers are prevalent, particularly among elderly men, and linked to conditions such as hyperparathyroidism and renal transplant.
Symptoms include severe epigastric pain related to meals, nausea, flatulence, and heartburn.
Gastric ulcers are associated with anorexia and weight loss.

Gastric Motility

The stomach can accommodate up to one liter of food without significant increase in intragastric pressure due to:
- Plasticity of the gastric wall and receptive relaxation.
- Law of LaPlace: Pressure (P) = Tension (T) / Radius (r).
The basic electrical rhythm (BER) in the stomach is approximately 3-5 cycles/min, initiating peristalsis and regulated by:
- Vagal stimulation and hormones like gastrin and motilin increasing spike potential rate.
- Sympathetic stimulation and hormones like secretin decreasing spike potential rate.

Peristaltic Movements

Peristalsis is neurogenic, dependent on local enteric plexus, and regulated by:
- Gastroenteric reflex: Distension of the stomach triggers intestinal peristalsis.
- Hormones: Gastrin, CCK, insulin, and glucagons enhance motility.
Types of peristalsis include ordinary peristalsis, peristaltic rush (mass peristalsis), and antiperistalsis.
Peristalsis speeds range from 1-5 cm/sec over short distances, facilitating chyme propulsion.

Intestinal Motility Control

Small intestinal motility controlled by:
- Nervous: Extrinsic (vagus nerve ↑ motility, sympathetic ↓ motility) and intrinsic (myenteric plexus).
- Hormonal: Gastrin and CCK ↑ motility, while secretin and glucagon ↓ motility.
Ileocecal sphincter functions to prevent retrograde movement of cecal contents into the ileum, tone maintained by intrinsic nerve plexus.

Defecation Reflex and Voluntary Control

Filling of the rectum leads to urge to defecate; signals sent to the brain.
If conditions are suitable: cerebral cortex prompts excitatory impulses for increased peristalsis and relaxation of anal sphincters.
If conditions are unsuitable: inhibitory impulses cause rectal wall relaxation and sphincter contraction to prevent defecation.

Constipation

Defined as decreased frequency of defecation, resulting in hard, dry feces due to excessive water absorption.
Common causes include frequent inhibition of defecation, laxative overuse, anal pain, hypothyroidism, depression, and hypercalcemia.
Spastic colon may occur due to anxiety, leading to alternating constipation and diarrhea.

Diarrhea

Characterized by frequent defecation of large volumes of soft stool.
Caused by irritation of intestinal mucosa from bacteria, viruses, parasites, or enterotoxins, leading to increased secretion and gastrointestinal motility.

Liver Functions

Bile formation and secretion roughly 0.2g bile salts/day; excretes bile pigments.
Stores glycogen, vitamins (A, D, E, K, B12), and metals (iron, copper), acting as a blood iron buffer.
Essential for erythropoiesis by providing vitamin B12, iron, and globin for hemoglobin synthesis.
Synthesizes plasma proteins and blood clotting factors (II, VII, IX, X) requiring vitamin K.
Filtration of blood via Kupffer cells, removing clots and bacteria from portal blood.

Gallbladder Motility

Contracts during meals to expel bile; sphincter of Oddi relaxes.
Factors enhancing bile evacuation include vagal stimulation, cholecystokinin, and magnesium sulfate.

Jaundice Types and Causes

Jaundice classified into pre-hepatic (hemolytic), intrahepatic, and post-hepatic (obstructive).
Pre-hepatic jaundice results from conditions like hereditary spherocytosis or thalassemias.
Intrahepatic jaundice commonly caused by hepatitis, liver cirrhosis, or certain drugs.
Post-hepatic jaundice typically due to biliary obstruction from stones or tumors.
Excessive RBC hemolysis leads to increased hemobilirubin and cholebilirubin in the blood and urine, causing yellow discoloration.

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Description

Test your knowledge on peptic ulcers and gastric motility. This quiz covers the causes, symptoms, and physiological mechanisms related to gastrointestinal health and disorders. Perfect for students learning about human biology and digestive systems.