Problem 10 - Objective Biology for NEET

Question

Cuboidal epithelium can be found in (a) Distal convoluted tubule (b) Proximal convoluted tubule (c) Henle's loop (d) Both (a) and (b)

Step-by-Step Solution

Answer

The cuboidal epithelium can be found in both the distal and proximal convoluted tubules (option d).

Step 1: Understand Cuboidal Epithelium

Cuboidal epithelium is a type of epithelial tissue that looks like many tiny cubes under a microscope. They are most commonly found in areas of the body where secretion and absorption occur.

Step 2: Apply Knowledge

Given this knowledge, the distal convoluted tubule and the proximal convoluted tubule, both parts of a nephron in the kidney, are lined with cuboidal epithelial cells to facilitate the reabsorption of water and electrolytes into the bloodstream.

Step 3: Answer the Question

Accordingly, it can be concluded that cuboidal epithelium can be found in both the distal convoluted tubule and proximal convoluted tubule. Therefore, the correct answer is (d) Both (a) and (b).

Key Concepts

Distal Convoluted Tubule

The distal convoluted tubule (DCT) is an important section of the nephron found in the kidney. Its primary role is to fine-tune the salt and water balance in the body. The DCT helps to regulate potassium, sodium, calcium, and pH levels in the blood.
It reabsorbs sodium ions while excreting potassium and hydrogen ions, playing a crucial part in maintaining the body's electrolyte balance.
The cells lining the distal convoluted tubule are cuboidal epithelial cells, which are specialized in absorbing and secreting ions. Their cuboidal shape provides ample surface area for these essential functions.

• Regulates salts and water balance
• Controls electrolytes such as potassium, sodium, and calcium
• Composed of cuboidal epithelial cells

Proximal Convoluted Tubule

The proximal convoluted tubule (PCT) is the first segment of the nephron in the kidney following the glomerulus. It is crucial for reabsorbing a large volume of water, ions, and nutrients from the filtrate.
Different from the distal convoluted tubule, the PCT reabsorbs about 65% of the sodium, water, and chloride that passes through it. It is also heavily involved in reabsorbing glucose and amino acids back into the bloodstream.
Like the DCT, the proximal convoluted tubule is also lined with cuboidal epithelial cells. These cells are equipped with microvilli, which increase the surface area for maximum reabsorption and secretion tasks.
The structure of PCT ensures that essential substances are not lost from the body.

• Reabsorbs water, ions, and nutrients
• Has microvilli for increased absorption
• Lined with cuboidal epithelium

Nephron Function

A nephron is the functional unit of the kidney, with each kidney containing millions. Its main function is filtering blood to remove waste and excess substances, which are then excreted as urine.
The nephron is composed of several parts: the glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct. Each part has a unique role in processing the filtrate from blood.
Important tasks the nephron handles include filtration, reabsorption, secretion, and excretion. These processes work together to keep our body's internal environment stable.

• Filters waste from the blood
• Composed of multiple segments
• Responsible for reabsorption and secretion

Epithelial Tissue

Epithelial tissue covers body surfaces and lines hollow organs, cavities, and ducts. In the context of the kidney, specifically the nephrons, the importance of epithelial tissue becomes evident in facilitating absorption and secretion.
This tissue type is categorized by shape and layering: simple (single layer) or stratified (multiple layers), and shapes such as squamous, cuboidal, and columnar.
In nephrons, we see cuboidal epithelial cells are significant because of their stability and ability to form a barrier while allowing selective reabsorption and secretion.
The structural arrangement of epithelial tissue plays a crucial role in the efficient functioning of nephron components like the proximal and distal convoluted tubules.

• Covers and lines body structures
• Facilitates selective absorption and secretion
• Crucial for nephron function

Kidney Reabsorption

Kidney reabsorption is a vital process by which water and solutes that were previously filtered out during blood filtration are reabsorbed back into the bloodstream. This process helps maintain balance and conserve substances essential for the body.
Reabsorption primarily occurs in the proximal convoluted tubules, which reclaim nutrients, water, and minerals before they can be excreted as waste.
It is the body's mechanism for maintaining fluid and electrolyte balance and preventing the loss of water, glucose, and other key ions.
Cuboidal epithelial cells play a decisive role in this process by providing the structural capability for efficient reuptake of these substances.

• Prevents loss of essential nutrients
• Occurs mostly in proximal convoluted tubules
• Vital for fluid and electrolyte balance