Questions: Monocytes leave the marrow via the bloodstream. As they enter tissues, they mature and become granulocytes. lymphocytes. macrophages. neutrophils. Which of the following is NOT correct regarding host defenses? First line of defense blocks portals of entry. Second line of defense include inflammation and phagocytosis. Third line of defense is lymphocyte-dependent and specific. Fourth line of defense provides long-term immunity.

Question 11:
The answer is the third one: macrophages.
Explanation:

• Granulocytes: These are a different type of white blood cell that includes neutrophils, eosinophils, and basophils. Monocytes do not mature into granulocytes.
• Lymphocytes: These are another type of white blood cell, including T cells and B cells, and are not derived from monocytes.
• Macrophages: Monocytes mature into macrophages when they enter tissues. Macrophages are important for phagocytosis and immune response.
• Neutrophils: These are a type of granulocyte and are not derived from monocytes.

Question 12:
The answer is the fourth one: Fourth line of defense provides long-term immunity.
Explanation:

• First line of defense blocks portals of entry: This is correct. The first line of defense includes physical and chemical barriers like skin and mucous membranes.
• Second line of defense includes inflammation and phagocytosis: This is correct. The second line involves non-specific responses like inflammation and phagocytosis by cells such as macrophages.
• Third line of defense is lymphocyte-dependent and specific: This is correct. The third line involves specific immune responses mediated by lymphocytes, such as T cells and B cells.
• Fourth line of defense provides long-term immunity: This is incorrect because there is no recognized "fourth line of defense" in the immune system. Long-term immunity is typically associated with the third line of defense through memory cells.

In summary, monocytes mature into macrophages when they enter tissues, and there is no fourth line of defense in the immune system.