Practice Quiz Over Immune System

White blood cells are the most important cells to the immune system because they play a crucial role in defending the body against pathogens and foreign substances. They are responsible for identifying and destroying harmful microorganisms, producing antibodies, and coordinating immune responses. Unlike red blood cells, which carry oxygen, or cheek cells and epithelial cells, which primarily serve protective and structural functions, white blood cells are specifically designed to combat infections and maintain overall immune health.

The first line of non-specific defense includes physical barriers such as skin, mucus, and bodily secretions. These barriers help to prevent the entry of pathogens into the body. The skin acts as a physical barrier, preventing the entry of pathogens. Mucus traps pathogens and other foreign particles, preventing them from entering the body. Bodily secretions, such as tears, saliva, and sweat, contain enzymes and other substances that can kill or inhibit the growth of pathogens. Together, these layers form the first line of defense against pathogens.

The immune system is able to repeatedly fight off pathogens by creating memory B and T cells. These cells remember the specific antibodies needed to kill a particular pathogen. When the same pathogen invades the body again, these memory cells quickly recognize it and produce the necessary antibodies to eliminate it. This process allows the immune system to mount a faster and more efficient response to the pathogen, preventing reinfection.

Infectious diseases can spread through physical contact, contaminated food/water, coughing, and sneezing. Physical contact with an infected person or contaminated surfaces can transfer the disease-causing pathogens. Consuming contaminated food or water can also introduce the pathogens into the body. Coughing and sneezing release respiratory droplets containing the pathogens, which can be inhaled by others and lead to infection. Telepathy is not a recognized mode of disease transmission.

Lymphocytes play the largest role in humoral immunity. They are a type of white blood cell that are responsible for producing antibodies, which are proteins that help to identify and neutralize foreign substances in the body. Lymphocytes are able to recognize specific antigens and initiate an immune response by producing antibodies that bind to and neutralize these antigens. This is a key mechanism in humoral immunity, which is the branch of the immune system that involves the production of antibodies to fight off infections and protect against future exposure to the same pathogen.

Humoral immunity and cell-mediated immunity are two different branches of the adaptive immune response. Humoral immunity primarily involves the production of antibodies by B cells, which can neutralize pathogens and mark them for destruction by other immune cells. On the other hand, cell-mediated immunity is mediated by T cells, specifically cytotoxic T cells, which directly kill infected or abnormal cells. Therefore, the correct answer is that humoral immunity involves antibody production while cell-mediated immunity involves T cells directly killing pathogenic cells.

Antibodies do not directly kill pathogens. Instead, they work by binding to the pathogens and marking them for destruction by other components of the immune system, such as phagocytes or complement proteins. This process helps to neutralize the pathogens and prevent them from causing harm to the body. Therefore, the statement is false.

White blood cells, also known as leukocytes, mature in the bone marrow and the thymus. The bone marrow is responsible for producing and maturing most types of white blood cells. The thymus, on the other hand, is involved in the maturation of a specific type of white blood cell called T lymphocytes or T cells. The brain and the blood are not sites where white blood cells mature.

The circulatory system and integumentary system interact the most with the immune system. The circulatory system transports immune cells, such as white blood cells, throughout the body to fight off infections and diseases. The integumentary system, which includes the skin, hair, and nails, acts as a barrier against pathogens and helps to prevent their entry into the body. Both systems play important roles in supporting and protecting the immune system.

An elevated white blood cell count and fever are signs that the first line of nonspecific defenses has been breached. When the body detects an infection or inflammation, it releases more white blood cells to fight off the invading pathogens. This increase in white blood cell count is known as leukocytosis, which can be detected through a blood test. Fever is another response triggered by the body's immune system to combat infections. It raises the body's temperature, creating an unfavorable environment for the pathogens to thrive. Therefore, an elevated white blood cell count and fever indicate that the body is actively responding to an infection, suggesting that the first line of defense has been compromised.