Blood Cells, Plasma, And Defense Mechanism Quiz

Explanation
The skin acts as a physical barrier that prevents bacteria from entering the body. It is the outermost layer of the body and provides a protective covering. Mucus, on the other hand, is a slimy substance that lines the respiratory and digestive tracts. It traps bacteria and other pathogens, preventing them from entering the body. Both the skin and mucus play a crucial role in defending against bacterial invasion.

Explanation
First-line defense mechanisms are the body's initial line of defense against pathogens and other harmful substances. These mechanisms are designed to operate at possible entry points, such as the skin, respiratory system, and digestive system, to prevent the entry of pathogens into the body. Therefore, the statement that first-line defense mechanisms operate at possible entry points is true.

Explanation
T cells are actually lymphocytes that form in the bone marrow but mature in the thymus gland, not the bone marrow. This is an important distinction as the thymus gland plays a crucial role in the development and maturation of T cells, which are a key component of the immune system.

Explanation
The immune response is the body's defense mechanism against foreign substances, such as pathogens or toxins. When these foreign materials invade the body, the immune system recognizes them as threats and activates a series of responses to eliminate them. These responses can include the production of antibodies, activation of immune cells, and inflammation. Therefore, the statement that the body's immune response is its reaction to invasion by foreign materials is true.

Explanation
Neutrophils and macrophages are two types of phagocytes. Phagocytes are cells that are responsible for engulfing and destroying foreign particles such as bacteria and dead cells in the body. Neutrophils are the most common type of phagocyte and are usually the first to arrive at the site of infection. They are highly mobile and can quickly move towards the site of infection. Macrophages, on the other hand, are larger and more specialized phagocytes. They are found in tissues throughout the body and are responsible for engulfing and breaking down larger particles. Both neutrophils and macrophages play crucial roles in the immune response against infections.

Explanation
it produces a protein called interferon

Explanation
When a pathogen cannot be neutralized, macrophages and lymphocytes combine to form a cluster of cells called granuloma.

Explanation
Antibodies are special proteins that are produced in lymphoid tissues and travel through the bloodstream. They play a crucial role in the immune system by identifying and neutralizing foreign substances such as bacteria and viruses. Antibodies are specifically designed to bind to specific antigens, triggering an immune response to eliminate the threat. Therefore, the correct answer is protein.

Explanation
Phagocytes are a type of white blood cells. They play a crucial role in the immune system by engulfing and destroying harmful microorganisms and foreign particles. These cells are responsible for protecting the body against infections and are an essential component of the body's defense mechanism.

Explanation
Saliva and tears contain enzymes that help break down the cell walls of bacteria, thereby preventing the bacteria from causing infections in the body. This is an important defense mechanism as it helps to neutralize and eliminate harmful bacteria that may enter the mouth or eyes. Increasing the numbers of white blood cells and balancing blood thickness are not roles of saliva and tears in protecting the body.