Gastrointestinal System

Gastrointestinal System Indian Medical PG Question 1: A patient presents to the emergency department with pain and distension of abdomen and absolute constipation. What is the investigation of choice ?

• A. Plain X-ray abdomen (Erect) (Correct Answer)
• B. Ultrasonography
• C. Barium meal follow-through
• D. Colonoscopy

Gastrointestinal System Explanation: ***Plain X-ray abdomen (Erect)*** - An erect plain X-ray of the abdomen is the initial and often diagnostic investigation for **bowel obstruction**, revealing **dilated bowel loops** and **air-fluid levels**. - It helps confirm the presence of obstruction and can sometimes indicate its location and severity, though it does not provide information about the cause. *Ultrasonography* - While ultrasound can detect **bowel dilation** and **peristalsis**, it is limited in visualizing the entire bowel and cannot reliably differentiate between various causes of obstruction. - It is more useful for assessing **extraluminal pathology** or **fluid collections** but less effective as a primary diagnostic tool for bowel obstruction. *Barium meal follow-through* - This study involves oral **barium administration** and serial X-rays to visualize the small bowel, but it is **contraindicated** in suspected bowel obstruction due to the risk of exacerbating the obstruction or causing **barium impaction**. - Its primary role is in evaluating chronic or partial obstructions, or malabsorption, not acute presentations with complete obstruction. *Colonoscopy* - **Colonoscopy** is an invasive procedure primarily used for diagnosis and treatment of **colonic pathology**, such as polyps, strictures, or bleeding. - It is **contraindicated** in acute, complete bowel obstruction due to the risk of **perforation** and is not the initial diagnostic choice for acute abdominal pain and absolute constipation.

Gastrointestinal System Indian Medical PG Question 2: Match the following: A) Glossopharyngeal nerve B) Spinal accessory nerve C) Facial nerve D) Mandibular nerve 1) Shrugging of shoulder 2) Touch sensation from the posterior one-third of the tongue 3) Chewing 4) Taste from the anterior two-thirds of the tongue

• A. A-3 , B-1 , C-4 , D-2
• B. A-2 , B-3 , C-4 , D-1
• C. A-4 , B-1 , C-2 , D-3
• D. A-2 , B-1 , C-4 , D-3 (Correct Answer)

Gastrointestinal System Explanation: ***A-2 , B-1 , C-4 , D-3*** - **A) Glossopharyngeal nerve (CN IX)** is responsible for **general sensation and taste from the posterior one-third of the tongue** [1]. (2). - **B) Spinal Accessory nerve (CN XI)** innervates the **sternocleidomastoid** and **trapezius muscles**, which are involved in shrugging the shoulders (1). - **C) Facial nerve (CN VII)** carries **taste sensation from the anterior two-thirds of the tongue** [1] (4) via the chorda tympani. - **D) Mandibular nerve (V3)**, a branch of the trigeminal nerve, innervates the muscles of mastication, enabling **chewing** (3). *A-3 , B-1 , C-4 , D-2* - This option incorrectly associates the **glossopharyngeal nerve** with chewing, which is a function of the mandibular nerve (V3). - It also incorrectly associates the **mandibular nerve** with touch sensation from the posterior one-third of the tongue, which is a function of the glossopharyngeal nerve [1]. *A-2 , B-3 , C-4 , D-1* - This option incorrectly links the **spinal accessory nerve** with chewing; this nerve primarily controls shoulder and neck movements. - It also incorrectly assigns shrugging of the shoulder to the **mandibular nerve** instead of the spinal accessory nerve. *A-4 , B-1 , C-2 , D-3* - This choice incorrectly attributes **taste from the anterior two-thirds of the tongue** to the glossopharyngeal nerve, which supplies the posterior one-third [1]. - It also incorrectly links **touch sensation from the posterior one-third of the tongue** to the facial nerve, which is involved in taste from the anterior two-thirds [1].

Gastrointestinal System Indian Medical PG Question 3: Fructose is transported by which transporter?

• A. GLUT 5 (Correct Answer)
• B. GLUT 4
• C. GLUT 3
• D. GLUT 7

Gastrointestinal System Explanation: ***GLUT 5*** - **GLUT 5** is the primary transporter responsible for **fructose absorption** in the intestine. - It facilitates **fructose diffusion** down its concentration gradient, independent of sodium. *GLUT 4* - **GLUT 4** is an **insulin-dependent** glucose transporter primarily found in **adipose tissue** and **skeletal muscle**. - Its translocation to the cell membrane is stimulated by insulin, allowing glucose uptake in response to fed states. *GLUT 3* - **GLUT 3** is a high-affinity glucose transporter found predominantly in **neurons** and the **brain**. - It ensures a constant supply of glucose to these vital tissues, even at low blood glucose concentrations. *GLUT 7* - **GLUT 7** is primarily expressed in the **endoplasmic reticulum** and is involved in **glucose-6-phosphate transport**. - It plays a crucial role in **gluconeogenesis** and glycogenolysis in the liver.

Gastrointestinal System Indian Medical PG Question 4: Maximum concentration of vitamin A is found in which organ?

• A. Liver (Correct Answer)
• B. Kidney
• C. Lung
• D. Heart

Gastrointestinal System Explanation: ***Liver*** - The **liver** is the primary organ for **storage of vitamin A** (retinyl esters), accounting for 90% of the body's total vitamin A content. - **Hepatic stellate cells** within the liver are specialized for storing the majority of this fat-soluble vitamin. *Kidney* - The **kidney** plays a role in **vitamin D metabolism** and excretion, but not significant vitamin A storage. - While it helps regulate blood levels of various substances, it does not accumulate large quantities of vitamin A. *Lung* - The **lung** does not serve as a major storage site for **vitamin A**. - Its primary functions are related to **gas exchange**, not nutrient storage. *Heart* - The **heart** is responsible for **pumping blood** throughout the body and has minimal involvement in vitamin A storage. - It utilizes certain vitamins for its metabolic processes but does not act as a primary reservoir.

Gastrointestinal System Indian Medical PG Question 5: What is the most important site for gastrin-producing cells?

• A. Cardia
• B. Fundus
• C. Antrum (Correct Answer)
• D. Duodenum

Gastrointestinal System Explanation: ***Antrum*** - The **G cells**, which produce gastrin, are most concentrated in the gastric **antrum**. - **Gastrin** plays a crucial role in stimulating parietal cells to secrete hydrochloric acid and promoting gastric motility. *Cardia* - The cardia is the entry point of the esophagus into the stomach and contains mostly **mucus-secreting cells** for protection against reflux. - It has a minimal number of gastrin-producing G cells compared to the antrum. *Fundus* - The **fundus** is primarily responsible for storing food and contains abundant parietal cells for **acid secretion** and chief cells for **pepsinogen production**. - While it does contain some endocrine cells, it is not the main site for gastrin production. *Duodenum* - The **duodenum** contains some G cells, but they are less abundant than in the gastric antrum. - Its primary role is digestion and absorption, with major secretions including **cholecystokinin** and **secretin**.

Gastrointestinal System Flashcard 1 of 5

Question: _____ cells are located in the body of the stomach and secrete HCl and intrinsic factor

Answer: Parietal

Gastrointestinal System Flashcard 2 of 5

Question: Slow waves of the GI tract are produced via cyclic opening of _____ channels (depolarization), followed by opening of K+ channels (repolarization)

Answer: Ca2+

Gastrointestinal System Flashcard 3 of 5

Question: One function of gastrin is to increase growth of _____ and parietal cells

Answer: gastric mucosa

Gastrointestinal System Flashcard 4 of 5

Question: Defecation reflex: 1.Sensory nerve fibres carry information from the stimulation of _____ receptors in the rectum at 55mmHg, to the spinal cord

Answer: stretch

Gastrointestinal System Flashcard 5 of 5

Question: MMCs migrate from the _____ to the distal ileum at a rate of about 5 cm/min

Answer: stomach