Problem 78 - Objective Biology for NEET

Question

Which of the following are effects of cortisol? (a) Anti-inflammatory (b) Immunosuppressant (c) Increases RBC production (d) All of these

Step-by-Step Solution

Answer

The correct answers are (a) Cortisol has anti-inflammatory effects, and (b) Cortisol acts as an immunosuppressant. Both (c) Increases RBC production and (d) All of these are incorrect.

Step 1: Anti-inflammatory effects of cortisol

Cortisol, often referred to as the 'stress hormone', does indeed have anti-inflammatory effects. It inhibits inflammation by suppressing immune response and preventing substances that cause inflammation from leaving the blood vessels and entering tissues.

Step 2: Immunosuppressant effects of cortisol

Cortisol has an immunosuppressive effect. It inhibits the immune system, reducing its ability to fight diseases. This is why it is often used in medicine to treat autoimmune diseases and to prevent graft rejection in organ transplant recipients.

Step 3: Cortisol's role in increasing RBC production

The claim that cortisol increases red blood cell production is incorrect. Cortisol does not directly influence red blood cell production. The hormone that stimulates the production of red blood cells is erythropoietin, not cortisol.

Step 4: Analyzing the 'all of these' option

Since it has been established that cortisol does not increase red blood cell production, the choice '(d) All of these' is also incorrect.

Key Concepts

Anti-Inflammatory Function

Cortisol is commonly known as a powerful anti-inflammatory hormone. When our body faces stress, cortisol levels rise and help to manage inflammation. This hormone achieves its anti-inflammatory function by blocking certain pathways in the immune system that would otherwise lead to inflammation. For instance, it prevents immune cells and inflammatory substances from leaving the blood vessels to enter tissues where inflammation might occur.
As a result, cortisol serves to control swelling, redness, and pain, which are all signs of inflammation. Its regulatory role allows for maintaining balance and reducing unnecessary inflammation that could harm the body's tissues.

Immunosuppressant Properties

Cortisol is also recognized for its immunosuppressant properties. This means that it can significantly lower the activity of the immune system. While a robust immune system is essential for fighting infections, there are scenarios where its suppression is desirable.
Cortisol suppresses the immune system by limiting the production and function of certain cells involved in immune responses. Because of this, it is widely used in medical treatments for autoimmune conditions, where the immune system attacks the body's own cells. Additionally, it helps in preventing organ transplant rejection, ensuring that the body does not view the new organ as a threat and attempt to attack it.

• Used in autoimmune disease treatments
• Helps prevent organ rejection post-transplant

These applications highlight how cortisol manages excessive or unwanted immune activity.

Red Blood Cell Production

Contrary to some misconceptions, cortisol does not directly increase red blood cell (RBC) production. Red blood cells are primarily responsible for transporting oxygen throughout the body, and their production is governed by a hormone called erythropoietin.
Erythropoietin, produced mainly by the kidneys, is the hormone that stimulates the bone marrow to increase the production of red blood cells, especially in response to low oxygen levels. Although cortisol plays a vital role in various bodily functions, influencing RBC production is not one of them. This particular point helps in clarifying common misunderstandings related to cortisol's effects.

Immune System Suppression

The suppression of the immune system by cortisol is a critical aspect of its function. This effect is beneficial in many clinical settings. By taming an overactive immune system, cortisol helps manage conditions where the immune system mistakenly targets the body's healthy cells.
Understanding how cortisol suppresses immunity involves recognizing its impact on various immune-related pathways. Cortisol reduces the influx and function of white blood cells, thus toning down the immune response. As a result, the body experiences less inflammation and reduced symptoms of immune overactivity.

• Calms overactive immune responses
• Reduces inflammation linked to immune actions

Therefore, while suppression might sound negative, it provides necessary checks and balances within the immune framework.