Question

Aging and damaged erythrocytes are removed from the circulation by ___________. a. myeoblasts b. monocytes c. macrophages d. mast cells

Short answer

Answer: Macrophages

Step-by-step solution

Understand the cell types listed in the options.

First, let's briefly review each cell type mentioned in the options: a. Myeoblasts: Precursor cells in the bone marrow that differentiate into muscle cells. b. Monocytes: Large white blood cells that play a role in immune response and can differentiate into macrophages and dendritic cells. c. Macrophages: Large white blood cells that engulf and digest cellular debris, foreign substances, microbes, and cancer cells in a process called phagocytosis. d. Mast cells: Cells found in connective tissues and play a crucial role in allergic response and inflammation.

Identify the correct cell type.

Based on our understanding of the roles played by each cell type, we can conclude that macrophages (option c) are the cells responsible for removing aging and damaged erythrocytes from the circulation, as they are involved in engulfing and digesting cellular debris.

Confirm the answer.

The correct answer is c. Macrophages. These cells play a crucial role in the immune system, removing aging and damaged erythrocytes from circulation via phagocytosis.

Key concepts

Macrophages

Macrophages are vital cells within the immune system. They belong to a category of white blood cells known as phagocytes. These cells are crucial because they help maintain body health by removing bothersome elements. Here’s how they work:

• They are formed from monocytes, which are another type of white blood cell that circulates in the bloodstream.
• Once monocytes leave the bloodstream and enter tissues, they differentiate into macrophages.
• These macrophages stay in various tissues, such as the liver or spleen, and are always on the lookout for foreign substances, like bacteria. They also dispose of old or damaged cells like erythrocytes (red blood cells).

Macrophages are important for managing inflammation and facilitating tissue repair. When they engulf and digest unwanted materials, they provide a clean slate for new, healthy cells. They are integral to what keeps our body systems in check and functioning smoothly.

Phagocytosis

Phagocytosis is a fascinating defensive process carried out mainly by macrophages. This process is like a cleaning crew for your body. Here's a closer look:

• It involves the engulfing and digestion of foreign particles, cells, or debris.
• Macrophages recognize these cells or foreign bodies as something to remove, either because they are no longer functioning properly or they are invading our body like bacteria or viruses.
• The process starts when the macrophage surrounds the targeted material. After encasing it in a part of its cell membrane, the material is brought inside the macrophage.
• Inside, the unwanted material is broken down by enzymes, effectively destroying it and any danger it poses.

Through phagocytosis, macrophages keep our blood and tissues clear of old cells and possible infection agents, ensuring our immune system remains efficient.

Aging Erythrocytes

Erythrocytes, or red blood cells, are pivotal to keeping us alive by transporting oxygen. However, they don't last forever. Here's what happens as they age:

• Erythrocytes live for about 120 days. As they age, they become less flexible and may accumulate damage.
• This is where macrophages come into play. In organs such as the spleen, these cells detect older erythrocytes that have seen better days.
• Recognizing their diminished function, macrophages engage in phagocytosis to remove aged erythrocytes from circulation.
• By doing so, they ensure that newer and more efficient erythrocytes take over, keeping oxygen transport efficient throughout the body.

The removal of aging erythrocytes is an essential process that supports the overall health of the organism, preventing potential blockages in the bloodstream caused by inefficient cells.