Problem 124 - Objective Biology for NEET

Question

Sterols, hydrocarbons and waxes are eliminated through (a) Liver (b) Lungs (c) Sebaceous glands (d) Sweat glands

Step-by-Step Solution

Answer

The correct answer is (c) Sebaceous glands

Step 1: Analysis of Choices

First, consider what is known about the function of each of these: the Liver, Lungs, Sebaceous glands, and Sweat glands. The liver mainly detoxifies harmful substances. The lungs excrete carbon dioxide and water. The sebaceous glands secrete an oily substance called sebum that contains lipids and waste products from metabolic processes. The sweat glands mainly regulate body temperature and excrete water and salts.

Step 2: Identify the Function Most Relevant to Elimination

After analyzing the functions of the given options,we can identify that the sebaceous glands deal primarily with lipids, such as sterols, hydrocarbons, and waxes. These types of substances can be excreted as part of the sebum secreted by the sebaceous glands.

Step 3: Selection of the correct choice

Considering the functions of the provided options, the sebaceous glands are the most suitable choice. They secrete an oily substance called sebum, which includes sterols, hydrocarbons, and waxes.

Key Concepts

Sebaceous Glands Function

The sebaceous glands are tiny glands in the skin that secrete an oily substance known as sebum. This sebum has multiple functions: it moisturizes and protects the skin, delivers antioxidants, and helps to maintain the skin's barrier function.

These glands are part of the body's integumentary system, which is the body's first line of defense against environmental hazards. Sebum contains various lipids, including sterols, hydrocarbons, and waxes, which are metabolic byproducts.

The elimination of these substances is essential to prevent their accumulation, which can lead to skin disorders. Sebum also has a role in temperature regulation by preventing excess evaporation of moisture from the skin.

Understanding Excretion Through Sebaceous Glands

While not commonly thought of as excretory organs, sebaceous glands contribute to ridding the body of certain waste products. By expelling excess sterols, hydrocarbons, and waxes alongside sebum, they perform a unique excretory function crucial for maintaining skin health and homeostasis.

Liver Detoxification

The liver plays a pivotal role in the detoxification of harmful substances that enter the body. These substances can range from environmental toxins to byproducts of normal cellular metabolism.

Liver cells, or hepatocytes, execute a complex set of chemical reactions that transform these toxic substances into less harmful compounds. This detoxification process occurs in two phases:

• Phase I: Enzymes, primarily from the cytochrome P450 family, modify toxins, often resulting in their activation.
• Phase II: Conjugation reactions then increase the water-solubility of the byproducts, making them easier to excrete via the kidneys or bile.

These detoxified substances are eliminated from the body through urine or feces. Additionally, the liver is responsible for metabolizing nutrients and regulating blood chemistry, further highlighting its critical excretory functions.

Sweat Glands Role in Excretion

Sweat glands, found throughout the human body, play a crucial role in thermoregulation and excretion. These glands produce and secrete sweat, a liquid comprised mostly of water, but also containing salts, urea, and other waste products.

There are two primary types of sweat glands:

Eccrine Glands

These are the most numerous and are responsible for producing a clear, odorless fluid primarily for cooling the body through evaporation.

Apocrine Glands

Found mainly in the armpit and groin area, they secrete a thicker fluid and are associated with body odor.
The process of sweating not only regulates body temperature but also facilitates the removal of excess salts and other soluble waste from the body. This excretory function of sweat glands complements the work done by the kidneys and the urinary system in maintaining the electrolyte balance and the overall homeostasis of the body.