Problem 3 - Objective Biology for NEET

Question

Which of the following is correct for epithelial tissue? (a) It is present only as inner lining (b) It is present only as outer lining (c) Contains very less intracellular matrix (d) All of these

Step-by-Step Solution

Answer

The correct answer is (C). Epithelial tissue contains very less intracellular matrix.

Step 1: Understanding Epithelial Tissue

Epithelial tissue, which is one of the four basic types of tissues in biology, has several basic characteristics. Epithelial tissues are commonly known for their protective role, as they form the outer layer of the skin and the inner linings of organs and body cavities. They also lack an intracellular matrix, essentially in comparison to connective tissue.

Step 2: Matching the Characteristics to the Options

After understanding the properties of the epithelial tissue, you can match them with the given options. \n(A) It is present only as an inner lining - This statement is partial, as epithelial tissue forms both the inner lining of organs and body cavities and the outer layer of our skin. \n(B) It is present only as outer lining - Similar to (A), this statement only covers half the truth. \n(C) Contains very less intracellular matrix - This statement is accurate as epithelial tissues indeed contain an insignificant amount of intracellular matrix as compared to other tissues.\n(D) All of these - Refers to all the options.

Step 3: Select the Correct Answer

Based on the analysis, the answer should be the option that correctly states the characteristics of the epithelial tissue. Both options (A) and (B) present half-truths. Thus, the answer should be option (C), which accurately states a characteristic of epithelial tissues. Option (D) is incorrect because it includes (A) and (B), which are partially true.

Key Concepts

Tissue Types

In biology, tissues are fundamental building blocks of the body. There are four primary types of tissues, each with distinct functions and characteristics. These are:

• Epithelial Tissue: This type covers surfaces either as an outer layer like skin or inner lining of organs. It plays roles in protection, secretion, and absorption.
• Connective Tissue: It supports and binds other tissues. This type has a significant intracellular matrix, unlike epithelial tissues.
• Muscle Tissue: Responsible for movement, muscle tissue can be voluntary or involuntary.
• Nervous Tissue: This tissue helps in transmitting signals between different parts of the body.

Epithelial tissue is unique in its close-packed cells and minimal matrix, performing specialized roles in covering and protection.

Protective Role of Tissues

Tissues are not just structural elements; they also have crucial protective functions. Epithelial tissue is particularly significant for protection due to its location.

• Outer Protection: As the skin's surface, it acts as the first line of defense against physical damage, pathogens, and dehydration.
• Internal Protection: In organs, it forms barriers and linings that protect against chemical exposure and microbial invasion.
• Special Functions: Some epithelial tissues are specialized for secretion, such as those in glands, or absorption, as seen in the intestines.

The protective qualities of epithelial tissue are enhanced by its tight cellular arrangement, limiting entry of harmful substances.

Intracellular Matrix

The intracellular matrix refers to the non-cellular component present within tissues. It provides support and regulates cell behavior. In the spectrum of tissue types, the composition and quantity of the matrix vary:

• Minimal in Epithelial Tissue: Epithelial tissue has a very scant matrix. Cells are tightly packed with little space between them, creating a unified protective barrier.
• Abundant in Connective Tissue: Unlike epithelial tissue, connective tissue contains a large amount of matrix, which supports and connects other tissues.
• Importance of the Matrix: It plays a pivotal role in tissue functions, such as providing structural support and mediating biochemical interactions.

Understanding the role of the intracellular matrix helps in grasping the unique characteristics of epithelial tissues, particularly why they are effective in protection and forming linings.