Which of the following would be a component of the body's first line of defense?
inflammation
mucous membranes
natural killer cells
phagocytes
The Correct Answer is B
A. Inflammation: Inflammation is part of the second line of defense, an innate immune response that occurs after pathogens bypass physical barriers. It involves leukocyte recruitment and vascular changes to fight infection.
B. Mucous membranes: Mucous membranes form a physical and chemical barrier that traps pathogens and prevents their entry into the body. They are a key component of the first line of defense, along with skin and secretions like saliva and tears.
C. Natural killer cells: Natural killer cells are part of the innate immune system’s second line of defense. They identify and destroy infected or abnormal cells but act after pathogens have entered the body.
D. Phagocytes: Phagocytes, such as neutrophils and macrophages, are part of the second line of defense. They engulf and destroy pathogens that have breached the first line of defense barriers.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
A. Veins only carry blood low in oxygen:This statement is false because pulmonary veins carry oxygenated blood from the lungs to the heart. Not all veins carry deoxygenated blood; the oxygen content depends on the circulation pathway.
B. Veins are our blood reservoirs:Veins are capacitance vessels that can hold large volumes of blood, acting as reservoirs. This property helps maintain circulatory stability and allows the body to adjust blood distribution as needed.
C. Blood pressure is low in veins:Venous pressure is significantly lower than arterial pressure because veins are farther from the pumping action of the heart and have thinner walls with less smooth muscle.
D. Veins have valves:Many veins, especially in the limbs, contain valves that prevent backflow and assist in returning blood to the heart against gravity. These valves are crucial for maintaining unidirectional flow.
E. There are no exceptions, all of the above are true:This is incorrect because statement A is false; veins do not exclusively carry deoxygenated blood.
Correct Answer is A
Explanation
A. Antigens are substances that activate the adaptive immune response:Antigens are molecules, often proteins or polysaccharides, that are recognized as foreign by the immune system. Their presence triggers B and T lymphocytes to mount a specific adaptive immune response, including antibody production and cell-mediated immunity.
B. Antigens are typically composed of nucleotides:Antigens are usually composed of proteins, glycoproteins, or polysaccharides, not nucleotides. While nucleic acids can sometimes act as antigens, they are not the typical composition of antigenic substances.
C. Antigens are produced by the body in response to a foreign invader:Antigens themselves are foreign molecules or markers; they are not produced by the body. The body produces antibodies or immune cells that recognize and respond to antigens.
D. Antigens are limited to one antigenic determinant per antigen molecule:Many antigens have multiple antigenic determinants (epitopes), allowing them to be recognized by multiple antibodies or T cell receptors. They are not limited to a single determinant.
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