91Ó°ÊÓ

An allergy is caused by the immune system reacting to a foreign protein to produce IgE molecules that recognize the protein. These IgE molecules become associated with mast cells that respond to future exposures to the protein by releasing histamines into the body. The diagram shows this release and also shows how a drug called an antihistamine can help an allergy sufferer reduce their allergy symptoms. Which of the following statements explains how an antihistamine helps restore homeostasis during an allergic reaction? a. Antihistamines prevent mast cells from becoming associated with IgE molecules that recognize the foreign protein allergen. b. Antihistamines prevent mast cells from releasing histamines and causing the unpleasant allergy symptoms. c. Antihistamines prevent histamines that have been released by mast cells from stimulating the itching and swelling of body tissues. d. Antihistamines prevent mast cells from producing histamines, which halts their effect on the body.

Step by step solution

01

- Understand the Role of Histamines

Histamines are chemicals released by mast cells in response to IgE molecules during an allergic reaction. They cause symptoms such as itching, swelling, and other unpleasant allergy symptoms.

02

- Understand What Antihistamines Do

Antihistamines are drugs that help reduce allergy symptoms by interfering with the function of histamines.

03

- Analyze Each Option

Evaluate the provided options to determine which one best describes how antihistamines function.

04

- Eliminate Incorrect Options

a. Antihistamines do not interfere with the association of IgE molecules with mast cells.b. Antihistamines do not prevent the release of histamines by mast cells.c. Antihistamines block the effect of histamines on body tissues, reducing symptoms like itching and swelling.d. Antihistamines do not stop mast cells from producing histamines.

05

- Select the Correct Answer

Based on the analysis, option c is correct as it explains that antihistamines prevent histamines from stimulating itching and swelling of body tissues.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

immune system

The immune system acts as the body's primary defense mechanism against foreign invaders like bacteria, viruses, and allergens. It comprises various cells and proteins that work together to identify and destroy harmful substances.
When an allergen enters the body, the immune system mistakenly recognizes it as a threat. This initiates a defense response aimed at neutralizing the allergen. Key players in this response include white blood cells, like lymphocytes and mast cells.

• Lymphocytes: Help identify and attack foreign substances.
• Mast Cells: Release chemicals that contribute to allergy symptoms.

Understanding the role of the immune system helps explain why allergic reactions occur and how they can be managed effectively.

allergic reaction

An allergic reaction is an exaggerated response by the immune system to a normally harmless substance called an allergen. Common allergens include pollen, pet dander, and certain foods.
During an allergic reaction, the immune system produces specific antibodies known as Immunoglobulin E (IgE) to target the allergen. These IgE molecules attach to mast cells, which are found in tissues throughout the body.
When the body is exposed to the allergen again, the attached IgE molecules signal the mast cells to release various chemicals, including histamines, leading to allergy symptoms such as itching, swelling, and redness.

• First Exposure: Immune system produces IgE antibodies against the allergen.
• Subsequent Exposure: Mast cells release histamines, causing symptoms.

Knowing how allergic reactions work can guide effective treatment strategies.

mast cells

Mast cells are a type of white blood cell involved in the immune response. They play a crucial role in allergic reactions by releasing chemicals like histamines.
These cells are primarily found in connective tissues and near body surfaces, such as the skin and respiratory tract.
During an allergic reaction, IgE molecules attached to mast cells recognize the allergen and trigger the release of histamines and other chemicals, causing symptoms like itching and swelling.

• Location: Connective tissues, skin, and respiratory tract.
• Function: Release histamines during allergic reactions.
• Trigger: Activated by IgE antibodies attached to their surface.

Understanding mast cells helps explain why certain allergy symptoms occur and how they can be alleviated.

histamines

Histamines are chemicals released by mast cells during an allergic reaction. They are responsible for many common allergy symptoms, including itching, swelling, and redness.
When histamines bind to receptors on various tissues, they increase blood flow and permeability, causing fluid to leak into surrounding tissues, leading to swelling and redness.
This is why antihistamines are commonly used to treat allergic reactions; they block histamine receptors, preventing the symptoms from manifesting.

• Role: Cause allergy symptoms like itching and swelling.
• Mechanism: Increase blood flow and fluid leakage in tissues.
• Solution: Antihistamines block histamine receptors to alleviate symptoms.

By understanding histamines, we can better grasp how antihistamines work in reducing allergy symptoms.

IgE molecules

Immunoglobulin E (IgE) molecules are specific types of antibodies produced by the immune system in response to allergens. They play a key role in allergic reactions.
IgE antibodies bind to allergens and then attach to mast cells, priming them to respond to subsequent exposures of the same allergen.
When the allergen re-enters the body, these IgE-bound mast cells release histamines and other chemicals, leading to allergy symptoms.

• Type: A specific form of antibody.
• Function: Bind to allergens and mast cells.
• Trigger: Cause mast cells to release histamines upon allergen exposure.

Understanding IgE molecules helps to explain the body's hypersensitivity to certain allergens and the resultant allergic response.