Gastrointestinal System Practice Questions

Q: Which of the following cells is responsible for destroying bacterial foreign bodies in liver sinusoids?

Kupffer cells. ***Kupffer cells***- These are resident **macrophages** specifically located within the **liver sinusoids**.- Their primary role is **phagocytosis**, enabling them to clear the blood of **bacteria**, old red blood cells, and other foreign particulate matter entering the liver via the portal vein.*Hepatocytes*- These are the main parenchymal cells of the liver, primarily responsible for metabolic functions such as **bile production**, **protein synthesis**, and **detoxification**.- They lack the specialized migratory and high-volume **phagocytic capacity** needed to clear circulating bacteria.*Ito cells*- Also known as **hepatic stellate cells**, they reside in the **Space of Dissé** and are specialized for storing **Vitamin A**.- Upon activation (e.g., due to injury), they differentiate into myofibroblasts and are central to **liver fibrosis**.*Sinusoidal endothelial cells*- These cells line the vascular space of the sinusoid and are characterized by numerous **fenestrations** (pores) that allow fluid exchange with the Space of Dissé.- Although they form the barrier, they are generally less active in high-capacity microbial clearance compared to the dedicated **Kupffer cell macrophages**.

Q: The image shows migrating motor complexes in various parts of gut. Identify the correct statement.

Occur every 100 minutes. ***Occur every 100 minutes*** - The Migrating Motor Complex (MMC) is a pattern of electromechanical activity observed in the gastrointestinal tract during fasting, typically occurring in cycles of **approximately 90-120 minutes**, or about every 100 minutes. - This cyclical activity during the interdigestive period serves to **clear residual indigestible material and bacteria** from the small intestine into the colon. *Triggered by secretin* - The MMC is primarily triggered by **motilin**, a polypeptide hormone that increases gastrointestinal motility. - **Secretin** is known to inhibit gastric acid secretion and stimulate bicarbonate and water secretion from the pancreas and bile ducts, but it is not the primary trigger for MMC. *Phase 3 has least activity* - Phase 3 of the MMC is characterized by a **burst of intense, regular propagated contractions** that sweep from the stomach to the ileum, often referred to as the "housekeeping wave." - This phase exhibits the **most vigorous motor activity**, not the least, as seen by the high-amplitude spike bursts in the image. *Intake of meal exaggerates the migrating motor complex* - The MMC is a **fasting phenomenon** and is **abolished or inhibited by the intake of a meal**. - Feeding initiates a different motor pattern characterized by continuous, irregular contractions, which serve to mix and propel chyme through the digestive tract.

Q: The following marked recordings in GIT are produced by:

Interstitial cells of Cajal. ***Interstitial cells of Cajal*** - The image displays characteristic **slow waves** (also known as basal electrical rhythm) and superimposed **spike potentials** in the gastrointestinal tract, which are generated by the interstitial cells of Cajal (ICCs). - ICCs act as **pacemaker cells** in the GI tract, initiating the bioelectrical activity that dictates the rhythm of smooth muscle contractions. *Smooth muscle* - While GI smooth muscle cells contract in response to these electrical activities, they **do not generate the slow waves or spike potentials** themselves. - Smooth muscle cells are responsible for **muscle tension**, as shown in the lower tracing, which is directly triggered by the spike potentials. *Myenteric plexus* - The myenteric plexus primarily consists of **neurons** that regulate GI motility and secretions, influencing the activity of smooth muscle cells and ICCs. - It does not directly produce the characteristic slow waves or spike potentials observed as the intrinsic electrical rhythm. *Parasympathetic stimulation* - Parasympathetic stimulation, primarily via the **vagus nerve**, generally **increases the frequency and amplitude** of slow waves and spike potentials. - However, it modulates the activity rather than initiating the intrinsic electrical rhythm itself.

Q: Which of the following are functions of the gall bladder? I. Reservoir for bile II. Production of bile III. Secretion of mucus IV. Concentration of bile Select the correct answer using the code given below :

I, III and IV. ***I, III and IV (Correct)*** - The gallbladder **stores bile** produced by the liver, acting as a reservoir (I) until it's needed for digestion. - It **concentrates bile** 5-20 fold (IV) by absorbing water and electrolytes through its epithelium. - The gallbladder epithelium **secretes mucin** (III), which forms a protective mucous layer. - The gallbladder does **NOT produce bile** (II) - this is exclusively a function of hepatocytes in the liver. *II, III and IV (Incorrect)* - This option incorrectly includes bile production (II), which is **not a function of the gallbladder**. - The **liver produces bile**; the gallbladder only stores and concentrates it. - While III and IV are correct functions, the inclusion of II makes this option wrong. *I, II and III (Incorrect)* - This option incorrectly states that the gallbladder produces bile (II), which is a **hepatic function**. - Additionally, it omits bile concentration (IV), which is one of the **primary functions** of the gallbladder. - Only I and III are correct in this combination. *I, II and IV (Incorrect)* - This option incorrectly includes bile production (II) as a gallbladder function. - The gallbladder's actual roles are **storage (I), concentration (IV), and mucus secretion (III)** - not bile production.

Q: Resection of which part of intestine does not significantly affect fluid and electrolyte balance?

Distal jejunum. ***Distal jejunum*** - The distal jejunum has significant **adaptive capacity** to take over the absorptive functions of other parts of the small intestine if they are resected. - Its resection typically has the **least impact** on fluid and electrolyte balance compared to other segments of the intestine, as critical absorption of most nutrients, water, and electrolytes occurs more proximally or distally. *Ileum* - The ileum is crucial for the absorption of **vitamin B12** and **bile salts**; its resection can lead to **malabsorption** and severe diarrhea. - Loss of bile salt absorption can result in **fat malabsorption** and lead to fluid and electrolyte disturbances. *Proximal jejunum* - The proximal jejunum is the primary site for the absorption of most **nutrients** (carbohydrates, proteins, fats), **water**, and **electrolytes**. - Its resection can lead to significant **malnutrition** and severe fluid and electrolyte imbalances due to widespread malabsorption. *Colon* - The colon is responsible for the final absorption of **water** and **electrolytes**, compacting stool for elimination. - Its resection can severely impair the body's ability to conserve water and electrolytes, leading to **dehydration** and electrolyte disturbances.

Q: Iron is absorbed predominantly in the

Duodenum. ***Duodenum*** - The **duodenum** is the primary site for iron absorption, with maximum absorption occurring in the **duodenum and proximal jejunum**. - Iron is absorbed in both **heme** and **non-heme** forms through specific transporters like **DMT1** (divalent metal transporter 1) and **ferroportin**. - The acidic pH from gastric secretions helps maintain iron in the soluble **ferrous (Fe²⁺) form**, which is readily absorbed in the duodenum. - The duodenal enterocytes have the highest concentration of iron transport proteins, making this the most efficient site for iron absorption. *Jejunum* - Some iron absorption can occur in the **proximal jejunum**, but it decreases progressively in the distal parts. - The jejunum primarily absorbs **carbohydrates**, **proteins**, **amino acids**, and **fats**. - While it contributes to iron absorption, it is not the predominant site. *Ileum* - The ileum is specialized for absorption of **vitamin B12** (via intrinsic factor), **bile salts**, and fat-soluble vitamins. - Iron absorption in the ileum is minimal compared to the duodenum. - By the time chyme reaches the ileum, most iron has already been absorbed in the proximal small intestine. *Stomach* - The stomach does not absorb iron but plays an important preparatory role. - Gastric **hydrochloric acid** (HCl) helps solubilize iron and convert ferric iron (Fe³⁺) to ferrous iron (Fe²⁺), which is the absorbable form. - **Intrinsic factor** is secreted here for vitamin B12 absorption, not iron.

Q: With reference to the role of fibre in diet, consider the following statements: 1. It inhibits faecal mutagen synthesis. 2. It reduces post-prandial glucose. 3. It decreases the transit time of food in the bowel. Which of the above represent(s) the role of fibre in our diet?

1, 2 and 3. ***1, 2 and 3*** - Dietary fiber aids in reducing the formation of **faecal mutagens** by diluting their concentration and promoting their excretion, thereby lowering the risk of colorectal cancer. - Fiber, especially **soluble fiber**, slows down the absorption of glucose from the digestive tract, which helps in reducing **post-prandial glucose** spikes and improving glycemic control. - It increases stool bulk and softness, which **decreases the transit time** of food through the bowel, preventing constipation and reducing exposure to potential toxins. *1 only* - This option is incomplete as it only includes the benefit of inhibiting faecal mutagen synthesis and ignores other established physiological roles of dietary fiber. - While fiber does inhibit faecal mutagen synthesis, it also has significant impacts on glucose metabolism and gut motility. *2 only* - This option is also incomplete, focusing solely on the reduction of post-prandial glucose. - It overlooks the crucial roles of fiber in gut health, such as inhibiting mutagen synthesis and regulating bowel transit time. *1 and 2 only* - This option recognizes the role of fiber in both **faecal mutagen synthesis** and **post-prandial glucose** control but fails to acknowledge its critical function in maintaining regular bowel movements. - Dietary fiber is well-known for its laxative effect and its ability to **decrease transit time**, which is a fundamental benefit for digestive health.

Q: Which transporter is responsible for the absorption of glucose in the intestine when a person is given Oral Rehydration Solution (ORS)?

SGLT-1. ***SGLT-1 (Sodium-Glucose cotransporter 1)*** - **SGLT-1** is the primary transporter responsible for the **active absorption of glucose** and galactose from the intestinal lumen into enterocytes, utilizing the electrochemical gradient of sodium. - The mechanism of **ORS** relies on the co-transport of sodium and glucose via SGLT-1, which also facilitates the osmotic movement of water, making it effective for rehydration. *GLP-1 (Glucagon-like peptide-1)* - **GLP-1** is an **incretin hormone** that stimulates insulin secretion and inhibits glucagon release from the pancreas, playing a role in glucose homeostasis. - It is not a transporter for glucose absorption from the intestine but rather a **signaling molecule** involved in metabolic regulation. *SGLT-2 (Sodium-Glucose cotransporter 2)* - **SGLT-2** is predominantly found in the **renal tubules**, where it is responsible for the majority of glucose reabsorption from the filtrate back into the bloodstream. - While it is a glucose transporter, its primary role is in the **kidney**, not in intestinal glucose absorption. *GLUT-1 (Glucose Transporter 1)* - **GLUT-1** is found in all cell types and is primarily responsible for **basal glucose uptake** by cells, particularly high in red blood cells and at the blood-brain barrier. - It is a **facilitated diffusion transporter** and is not the primary mechanism for glucose absorption from the intestinal lumen.

Q: A child presented with dehydration and was supplemented with ORS solution for management. Which of the following transporters help in the absorption of glucose from GIT?

SGLT 1. ***SGLT 1*** - **SGLT1 (Sodium-Glucose Co-transporter 1)** is responsible for the **active transport of glucose and galactose** from the intestinal lumen into the enterocytes, coupled with sodium. - The principle of **oral rehydration solutions (ORS)** relies on this co-transport mechanism, as glucose (or other carbohydrates like sucrose, which is broken down into glucose and fructose) facilitates the absorption of sodium and water across the intestinal wall. *GLUT 2* - **GLUT2** is primarily located on the **basolateral membrane of enterocytes** and facilitates glucose transport out of the cell into the bloodstream. It also plays a role in glucose uptake in the liver and pancreatic beta cells. - While involved in glucose handling, **GLUT2 does not absorb glucose from the intestinal lumen** into the enterocytes; rather, it transports glucose out of them. *SGLT 2* - **SGLT2 (Sodium-Glucose Co-transporter 2)** is predominantly found in the **proximal tubules of the kidneys**, where it is responsible for the reabsorption of the vast majority of filtered glucose back into the bloodstream. - It is not involved in **intestinal glucose absorption**. Selective SGLT2 inhibitors are used as antidiabetic drugs to promote glucose excretion via the kidneys. *GLUT 1* - **GLUT1 (Glucose Transporter 1)** is a ubiquitous glucose transporter found in nearly all cell types, particularly important for basal glucose uptake by tissues like the **brain** and **red blood cells**. - While essential for glucose transport in many tissues, **GLUT1 plays a negligible role in glucose absorption from the gastrointestinal tract**.

Q: A woman must vomit whenever she eats spicy food. Arrange the sequence of events during vomiting. 1. LES is open and UES is closed 2. Strong contractions in the stomach 3. Inspiration against a closed glottis 4. Relaxation of the pyloric sphincter 5. LES opens and UES opens 6. Reverse peristalsis in the small intestine LES: Lower esophageal sphincter UES: Upper esophageal sphincter

6,4,2,3,1,5. ***6,4,2,3,1,5*** - The correct sequence of vomiting begins with **reverse peristalsis in the small intestine (6)**, which propels intestinal contents retrograde toward the stomach. - The **pyloric sphincter then relaxes (4)**, allowing duodenal contents to enter the stomach and mix with gastric contents. - **Strong stomach contractions (2)** follow, building initial pressure within the gastric lumen. - **Deep inspiration against a closed glottis (3)** is critical—this generates high intra-abdominal and intrathoracic pressure (the essential expulsive force). - The **LES opens while UES remains closed (1)**, allowing gastric contents to move into the esophagus. - Finally, the **UES opens (5)**, permitting expulsion of contents through the mouth. *4,6,2,1,3,5* - Incorrect because **pyloric sphincter relaxation precedes reverse peristalsis**, which is physiologically backwards—intestinal contents must first move toward the stomach before the pylorus can allow them entry. - The positioning of glottis closure late in the sequence misrepresents when intra-abdominal pressure is generated. *4,6,2,5,3,1* - This sequence incorrectly places **both sphincters opening (5) before the critical pressure-generating step (3)**, which would result in premature expulsion without adequate force. - The inspiration against closed glottis must occur before final sphincter opening to create the necessary expulsive pressure. *6,4,2,5,1,3* - This option misorders the final events by having **both sphincters open (5) before adequate pressure generation (3)** and before the sequential LES opening (1). - The glottis closure step is positioned too late—it must precede sphincter opening to generate the high intra-abdominal pressure required for forceful expulsion.

Question 1

Which of the following cells is responsible for destroying bacterial foreign bodies in liver sinusoids?

Accepted Answer

Kupffer cells

Answer

Hepatocytes

Answer

Sinusoidal endothelial cells

Answer

Ito cells

Question 2

The image shows migrating motor complexes in various parts of gut. Identify the correct statement.

Accepted Answer

Occur every 100 minutes

Answer

Triggered by secretin

Answer

Phase 3 has least activity

Answer

Intake of meal exaggerates the migrating motor complex

Question 3

The following marked recordings in GIT are produced by:

Accepted Answer

Interstitial cells of Cajal

Answer

Smooth muscle

Answer

Myenteric plexus

Answer

Parasympathetic stimulation

Question 4

Which of the following are functions of the gall bladder?
I. Reservoir for bile
II. Production of bile
III. Secretion of mucus
IV. Concentration of bile

Select the correct answer using the code given below :

Accepted Answer

I, III and IV

Answer

II, III and IV

Answer

I, II and III

Answer

I, II and IV

Question 5

Resection of which part of intestine does not significantly affect fluid and electrolyte balance?

Accepted Answer

Distal jejunum

Answer

Ileum

Answer

Proximal jejunum

Answer

Colon

Question 6

Iron is absorbed predominantly in the

Accepted Answer

Duodenum

Answer

Jejunum

Answer

Ileum

Answer

Stomach

Question 7

With reference to the role of fibre in diet, consider the following statements:
1. It inhibits faecal mutagen synthesis.
2. It reduces post-prandial glucose.
3. It decreases the transit time of food in the bowel.
Which of the above represent(s) the role of fibre in our diet?

Accepted Answer

1, 2 and 3

Answer

1 only

Answer

2 only

Answer

1 and 2 only

Question 8

Which transporter is responsible for the absorption of glucose in the intestine when a person is given Oral Rehydration Solution (ORS)?

Accepted Answer

SGLT-1

Answer

GLP-1

Answer

SGLT-2

Answer

GLUT-1

Question 9

A child presented with dehydration and was supplemented with ORS solution for management. Which of the following transporters help in the absorption of glucose from GIT?

Accepted Answer

SGLT 1

Answer

GLUT 2

Answer

SGLT 2

Answer

GLUT 1

Question 10

A woman must vomit whenever she eats spicy food. Arrange the sequence of events during vomiting.

1. LES is open and UES is closed
2. Strong contractions in the stomach
3. Inspiration against a closed glottis
4. Relaxation of the pyloric sphincter
5. LES opens and UES opens
6. Reverse peristalsis in the small intestine

LES: Lower esophageal sphincter
UES: Upper esophageal sphincter

Accepted Answer

6,4,2,3,1,5

Answer

4,6,2,1,3,5

Answer

4,6,2,5,3,1

Answer

6,4,2,5,1,3

Gastrointestinal System — MCQs

Gastrointestinal System — MCQs

On this page

Practice by Chapter

Want unlimited practice?