Question

Foreign particles circulating in the blood are filtered by the __________. a. spleen b. lymph nodes c. MALT d. lymph

Short answer

Answer: a. spleen

Step-by-step solution

Explanation of Answer Choices

Let's look at each answer choice and discuss their functions: a. Spleen - A soft, spongy organ part of the immune system that filters blood, destroys old or damaged red blood cells, and stores blood and platelets. b. Lymph Nodes - Small, bean-shaped structures that produce and store cells that fight infections and other diseases. They filter lymph, not blood. c. MALT - Mucosa-associated lymphoid tissues, located in the gut wall. They form part of the first line of defense and initiate immune responses against pathogens. d. Lymph - A colorless fluid containing white blood cells. It circulates through the lymphatic system that helps rid the body of toxins and waste.

Select the Correct Answer

Based on the explanations above, the answer is a. spleen. The spleen is the organ responsible for filtering foreign particles circulating in the blood, while the other options are either involved in the immune system in a different way or are not directly involved in filtering blood.

Key concepts

Lymph Nodes

Lymph nodes are an integral part of our immune system. These small, bean-shaped structures play a crucial role in helping our body fight infections and diseases.
They are distributed throughout the body in clusters, such as those found in the neck, armpits, and groin areas. What makes lymph nodes so unique?

• They act as filters for lymph, a fluid that circulates through the lymphatic system.
• They trap and destroy bacteria, viruses, and other foreign substances.
• Within the lymph nodes, immune cells, like lymphocytes, are stored and become activated when a pathogen is detected.

Thanks to lymph nodes, our body is able to monitor and respond to foreign threats effectively, keeping us healthy and protected.

MALT

Mucosa-associated lymphoid tissues (MALT) are an important part of our body's defense mechanism. MALT comprises tissues found at mucosal surfaces, including those in the digestive, respiratory, and urogenital tracts.
These tissues serve as the first line of defense against pathogens that enter the body via these pathways.

• MALT responds quickly to incoming pathogens, providing an initial immune response without needing prior exposure to the antigen.
• It includes structures such as the tonsils, Peyer's patches in the intestine, and the appendix.
• MALT contains densely packed immune cells that can recognize and react to antigens.

By maintaining vigilance at key entry points, MALT helps prevent infections from establishing themselves in the body.

Lymph

Lymph is a clear fluid that plays a pivotal role in maintaining fluid balance and supporting the immune system in our body. As it travels through the lymphatic vessels, it collects and removes waste products, bacteria, and other unwanted materials from tissue spaces.
Lymph acts as a communication highway for the immune system.

• It carries white blood cells, particularly lymphocytes, which help fight against infections.
• As lymph moves through the lymphatic system, it eventually reaches the lymph nodes for filtration.
• The lymphatic system returns cleaned lymph to the bloodstream, ensuring that our circulatory system remains efficient.

Through its filtration and transport functions, lymph ensures that our body's internal environment remains clean and well-defended.