The part of the colon that absorbs the remaining water and other key nutrients from the indigestible material, solidifying it to form stool is:

1. A

   Ascending colon

2. B

   Descending colon

3. C

   Rectum

4. D

   Transverse colon

Appeared in: AIIMS Jodhpur SNO-2023

Explanation

• The descending colon is the part of the large intestine that runs down the left side of the abdomen.
• Its primary functions are to absorb the final amounts of water and electrolytes from indigestible material.
• This absorption process is what solidifies the semi-liquid waste into formed stool.
• The descending colon also serves as a storage site for feces before they move into the sigmoid colon and rectum for eventual elimination.

Why Other Options Were Wrong

• Option A: The ascending colon is the first part of the large intestine. While it is a major site of water and electrolyte absorption, it primarily deals with liquid chyme coming from the small intestine. It does not handle the final solidification process.
• Option C: The rectum's main function is the temporary storage of fully formed feces before defecation. It does not play a significant role in water absorption.
• Option D: The transverse colon continues the process of water absorption, and the chyme becomes more semi-solid. However, it is not the primary site for absorbing the remaining water to fully solidify the stool.

Related Visual

• Visual 1: Diagram: Anatomy of the large intestine. A clear diagram showing the path of waste through the ascending, transverse, descending, and sigmoid colon, and finally the rectum. This helps visualize the location and sequence of each part's function.

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy and Physiology of the Large Intestine as background academic context rather than a clinical decision trigger.
• Understanding the specific functions of each colon segment is crucial for nurses when assessing bowel-related issues. For example, the location of abdominal pain can suggest which part of the colon is affected.
• Knowledge of colon physiology helps in managing conditions like constipation and diarrhea. For constipation, interventions aim to increase water content in the stool, while for diarrhea, the goal is to manage fluid loss from rapid transit.
• What if a patient has a left hemicolectomy (removal of the descending colon)? The nurse should anticipate that the patient will have looser and more frequent stools because the final site for water absorption and stool solidification has been removed.

How to Approach the Question

• First, identify the key terms in the question: 'colon', 'absorbs remaining water', and 'solidifying... stool'.
• Recall the anatomical path of the large intestine: cecum -> ascending colon -> transverse colon -> descending colon -> sigmoid colon -> rectum.
• Think about the state of the digested material (chyme/stool) as it passes through each section.
• The chyme is liquid in the ascending colon, where most water absorption begins.
• It becomes semi-solid in the transverse colon as more water is absorbed.
• The term 'remaining water' points to the final stage of absorption, which occurs in the descending colon, leading to 'solidifying' the stool.

Concept Tested & Keywords

• Concept Tested: Anatomy and Physiology of the Large Intestine
• Stem keywords: colon, absorbs, remaining water, nutrients, indigestible material, solidifying, stool
• Lead-in keywords: The part of the colon that
• Negative lead-in flag: false

Question ID

QlSnLBJH12XGBA9Y0jD1OC

Copy ID

Reference Book

E6 Anatomy Grays 43e Vol 2 Part 1 p. 459-462