1.
All of the following are characteristic components of nonspecific host defenses EXCEPT
Correct Answer
B. Antibodies
Explanation
Nonspecific host defenses refer to the immune responses that are not specific to a particular pathogen. These defenses act as the first line of defense against infections. Fever is a characteristic component of nonspecific host defenses as it helps to inhibit the growth of pathogens and enhances the immune response. Antibodies, on the other hand, are part of the specific immune response and are produced in response to a specific pathogen. They help to neutralize and eliminate the pathogen from the body. Therefore, antibodies are not considered as characteristic components of nonspecific host defenses.
2.
Which of the following is NOT a chemical barrier
Correct Answer
B. Complement protein
Explanation
Complement proteins are not considered a chemical barrier. They are part of the immune system and play a role in the body's defense against pathogens. They help to enhance the immune response by promoting inflammation, attracting immune cells, and directly killing pathogens. On the other hand, mucous membranes act as a physical and chemical barrier, preventing the entry of pathogens into the body. They produce mucus, which traps pathogens and contains antimicrobial substances that can kill or inhibit their growth. Therefore, complement proteins do not function as a chemical barrier.
3.
Blood consists partly of formed elements which include all of the following EXCEPT
Correct Answer
B. Plasma
Explanation
Blood consists of formed elements, which are the cellular components of blood, and plasma, which is the liquid portion of blood. The formed elements include red blood cells, white blood cells, and platelets. However, the question asks for the exception, so the correct answer is plasma.
4.
A granulocyte that releases the inflammatory agent histamine
Correct Answer
B. BasopHil
Explanation
A basophil is a type of granulocyte that releases histamine, an inflammatory agent. Histamine is involved in the immune response and plays a role in allergic reactions and inflammation. Basophils are characterized by the presence of granules in their cytoplasm, which contain histamine and other chemicals. When basophils are activated, they release histamine into the surrounding tissues, causing vasodilation and increased permeability of blood vessels, which leads to the characteristic symptoms of inflammation. Eosinophils, on the other hand, are also granulocytes but are primarily involved in combating parasitic infections and allergies, rather than releasing histamine.
5.
Histiocytes,kupffer cells and osteoclasts are members of which of the following types of cells
Correct Answer
B. Fixed macropHages
Explanation
Histiocytes, Kupffer cells, and osteoclasts are all examples of fixed macrophages. Fixed macrophages are a type of immune cell that reside in specific tissues and organs, such as the skin, liver, and bone. They play a crucial role in the immune response by engulfing and destroying foreign particles, pathogens, and dead cells. These cells are called "fixed" because they are stationary in their respective tissues, unlike other types of macrophages that can move throughout the body.
6.
A multilobed lymphatic organ that functions to process lymphocytes and release them into the blood as T-cells is
Correct Answer
B. Thymus gland
Explanation
The thymus gland is a multilobed lymphatic organ that plays a crucial role in the development and maturation of T-cells, a type of lymphocyte. It processes lymphocytes, allowing them to mature and differentiate into functional T-cells. These T-cells are then released into the bloodstream, where they play a vital role in the immune response, helping to identify and destroy infected or abnormal cells. The tonsils, on the other hand, are also lymphatic organs but primarily function as a defense mechanism against pathogens entering the body through the mouth and throat.
7.
Heat,pain,redness and swelling are symptoms of
Correct Answer
B. Inflammation
Explanation
Heat, pain, redness, and swelling are classic symptoms of inflammation. Inflammation is the body's natural response to injury or infection. When tissues are damaged, immune cells are recruited to the site, causing increased blood flow and release of chemicals that trigger inflammation. This leads to heat, pain, redness, and swelling in the affected area. Phagocytosis, on the other hand, is a process by which cells engulf and digest foreign particles, such as bacteria, but it does not typically result in the symptoms mentioned.
8.
What chemical substance diffuses into venules and capillaries causing their vasodilation during inflammation
Correct Answer
B. Histamine
Explanation
Histamine is the correct answer because it is a chemical substance that diffuses into venules and capillaries during inflammation, causing their vasodilation. Histamine is released by mast cells and basophils in response to injury or infection, and it acts as a potent vasodilator, increasing blood flow to the affected area. This increased blood flow helps to deliver immune cells and nutrients to the site of inflammation, promoting the healing process. Bradykinin is also involved in inflammation but does not directly cause vasodilation.
9.
During inflammation permeable capillary walls allow accumulation of fluids near injured cells causing which of the following
Correct Answer
B. Edema
Explanation
During inflammation, the permeable capillary walls allow the accumulation of fluids near injured cells. This accumulation of fluid is known as edema. Edema causes swelling and can lead to pain, redness, and warmth in the affected area.
10.
What consists of tissue debris remains of digested microorganisms,injured cells and dead phagocytes
Correct Answer
A. Pus
Explanation
Pus consists of tissue debris, remains of digested microorganisms, injured cells, and dead phagocytes. It is a thick, yellowish-white fluid that is produced in response to infection or inflammation. The presence of these components in pus indicates an ongoing immune response to clear the infection or heal the injured tissue.
11.
The process whereby immune cells leave the blood by passing between the endothelial cells that line blood vessels is known as
Correct Answer
B. Diapedesis
Explanation
Diapedesis is the process by which immune cells exit the bloodstream by squeezing between the endothelial cells that line the blood vessels. This allows the immune cells to migrate to the site of infection or injury, where they can perform their protective functions. Leukocytosis, on the other hand, refers to an increase in the number of white blood cells in the bloodstream, which can occur in response to infection or inflammation. Therefore, diapedesis is the correct term to describe the process of immune cells leaving the blood vessels.
12.
A protein that interferes with the ability of a virus to replicate inside a host cell
Correct Answer
B. Interferon
Explanation
Interferon is a protein that plays a crucial role in the immune response against viral infections. It is produced by host cells in response to viral invasion and acts as a defense mechanism by interfering with the ability of the virus to replicate inside the host cell. By inhibiting viral replication, interferon helps to limit the spread of the virus and control the infection. Therefore, interferon is the correct answer as it describes a protein that interferes with the ability of a virus to replicate inside a host cell.
13.
The classical pathway of complement activation involves which of the following proteins?
Correct Answer
A. C1, C4, and C2
Explanation
The classical pathway of complement activation involves the proteins C1, C4, and C2. These proteins work together to initiate the complement cascade, which is a series of biochemical reactions that help the immune system to eliminate pathogens. C1 binds to antibodies that are bound to pathogens, leading to the activation of C4 and C2. The activated forms of C4 and C2 then come together to form the C3 convertase, which cleaves C3 into C3a and C3b. This triggers a series of downstream reactions that ultimately lead to the destruction of the pathogen.
14.
Complement activation results all of the following physological processes EXCEPT
Correct Answer
B. Fever
Explanation
Complement activation is a part of the immune response that helps in the elimination of pathogens. It can lead to various physiological processes, including opsonization, which enhances phagocytosis of pathogens by immune cells. However, complement activation does not directly result in fever. Fever is typically triggered by the release of certain chemicals called pyrogens, which act on the hypothalamus to raise the body temperature. While complement activation can indirectly contribute to fever by promoting inflammation, it is not the direct cause of fever itself.
15.
Specific defenses function against any infectious agent while nonspecific defenses respond to particular infectious agents
Correct Answer
B. False
Explanation
This statement is false. Specific defenses respond to particular infectious agents, while nonspecific defenses function against any infectious agent. Specific defenses include the immune response, which specifically targets and eliminates specific pathogens. Nonspecific defenses, on the other hand, provide a general barrier against a wide range of pathogens and include physical barriers like the skin, as well as chemical defenses like stomach acid and antimicrobial proteins.
16.
Phagocytes and interferon are physical barriers of nonspecific defenses
Correct Answer
B. False
Explanation
The statement is false because phagocytes and interferon are not physical barriers but rather part of the cellular response of the immune system. Phagocytes are a type of white blood cell that engulfs and destroys pathogens, while interferon is a protein that helps to inhibit the spread of viruses in the body. These are examples of specific defenses rather than physical barriers.
17.
Neutrophils are phagocytic leukocytes that contain oxidative chemicals to kill internalized microorganisms
Correct Answer
A. True
Explanation
Neutrophils are a type of white blood cell that play a crucial role in the immune response by engulfing and destroying microorganisms through a process called phagocytosis. They contain oxidative chemicals, such as hydrogen peroxide and hypochlorous acid, which are used to kill the internalized microorganisms. This statement is true as it accurately describes the phagocytic and microbicidal properties of neutrophils.
18.
Granulocytes include basophils,neutrophils,and eosinophils
Correct Answer
A. True
Explanation
Granulocytes are a type of white blood cell that contain granules in their cytoplasm. They play a crucial role in the immune system's response to infections and allergies. Basophils, neutrophils, and eosinophils are all types of granulocytes. Basophils release histamine, which is involved in allergic reactions. Neutrophils are the most abundant type of white blood cell and are responsible for fighting bacterial infections. Eosinophils are involved in fighting parasitic infections and are also associated with allergic reactions. Therefore, the statement that granulocytes include basophils, neutrophils, and eosinophils is true.
19.
Lymphocytes and monocytes are considered agranulocytes because they contain granules in their cytoplasm
Correct Answer
B. False
Explanation
Lymphocytes and monocytes are actually considered agranulocytes because they do not contain granules in their cytoplasm. Agranulocytes lack visible granules in their cytoplasm, while granulocytes, such as neutrophils, eosinophils, and basophils, have visible granules. Therefore, the statement that lymphocytes and monocytes contain granules in their cytoplasm is incorrect.
20.
Mast cells and basophils both release histamine
Correct Answer
A. True
Explanation
Mast cells and basophils are both types of white blood cells that play a role in the immune response. One of their functions is to release histamine, a chemical mediator involved in allergic reactions and inflammation. Histamine is released in response to various triggers, such as allergens or injury, and it causes vasodilation, increased vascular permeability, and smooth muscle contraction. Therefore, the statement that mast cells and basophils both release histamine is true.
21.
The acid fast cell wall of mycobacterium contributes to this organism's ability to resist the lysosomal activity of phagocytic cells
Correct Answer
A. True
Explanation
The acid-fast cell wall of mycobacterium is composed of a unique lipid called mycolic acid, which makes it resistant to the lysosomal enzymes present in phagocytic cells. This enables mycobacterium to survive and multiply within these cells, evading the immune response and causing persistent infections. Therefore, the statement that the acid-fast cell wall contributes to the organism's ability to resist lysosomal activity of phagocytic cells is true.
22.
In humans T-cells and B-cells constitute the vast majority of lymphocytes
Correct Answer
A. True
Explanation
T-cells and B-cells are two types of lymphocytes that play a crucial role in the immune system of humans. They are responsible for recognizing and attacking foreign substances such as bacteria and viruses. As they constitute the majority of lymphocytes, it indicates their importance in defending the body against infections and diseases. Therefore, the statement "In humans, T-cells and B-cells constitute the vast majority of lymphocytes" is true.
23.
The complement system consist of over 20 proteins that function in cascade like manner.
Correct Answer
A. True
Explanation
The complement system is a complex network of proteins that work together in a cascade-like manner. This means that when one protein is activated, it triggers a series of reactions that lead to the activation of other proteins in a sequential manner. This cascade-like activation is essential for the proper functioning of the complement system in immune responses. Therefore, the statement that the complement system consists of over 20 proteins that function in a cascade-like manner is true.
24.
Complement activation results in the onset of fever
Correct Answer
B. False
Explanation
Complement activation does not directly result in the onset of fever. Fever is typically caused by the release of certain chemicals called pyrogens, which can be produced by various immune cells in response to infection or inflammation. While complement activation is an important part of the immune response and can contribute to inflammation, it is not the direct cause of fever. Therefore, the statement is false.
25.
------- defenses respond to particular infectious agensts called antigens
Correct Answer
specific
Explanation
Defenses in the body are designed to respond to specific infectious agents called antigens. This means that the immune system recognizes and targets specific antigens, such as bacteria, viruses, or other foreign substances, in order to eliminate them and protect the body from infection. This specificity allows the immune system to mount a targeted response, producing antibodies or activating immune cells that are specifically tailored to combat the particular antigen encountered. By having a specific response, the body can efficiently and effectively fight off different types of pathogens.
26.
Skin and mucous membrane are a part of ------ barriers
Correct Answer
physical
Explanation
Skin and mucous membranes act as physical barriers in the body's defense system. They provide a physical barrier between the external environment and the internal tissues, preventing the entry of pathogens and other harmful substances. The skin acts as a protective layer, while mucous membranes line the respiratory, digestive, and reproductive tracts, trapping pathogens and preventing their entry into the body. These physical barriers play a crucial role in preventing infections and maintaining overall health.
27.
Phagocytes tht are called ------- are known as the"big eaters" of microorganisms and foreign particles
Correct Answer
macrophages
Explanation
Macrophages are a type of phagocyte that are known for their ability to engulf and digest microorganisms and foreign particles. They play a crucial role in the immune response by recognizing and eliminating these harmful substances. Macrophages are larger in size compared to other phagocytes, hence the term "big eaters." Their function is essential in maintaining the body's defense against infections and promoting overall immune health.
28.
B and T lymphocytes are derived from ---- stem cells
Correct Answer
lymphoid
Explanation
B and T lymphocytes are types of white blood cells that are crucial for the immune response. They are derived from lymphoid stem cells, which are responsible for producing cells of the lymphoid lineage. These stem cells differentiate and mature into B and T lymphocytes, which play a vital role in recognizing and attacking foreign substances in the body. The lymphoid stem cells are found in the bone marrow and lymphoid tissues, such as the spleen and lymph nodes.
29.
Myeloid stem cells and lymphoid stem cells arise from ----- stem cells
Correct Answer
pluripotent
Explanation
Myeloid stem cells and lymphoid stem cells arise from pluripotent stem cells. Pluripotent stem cells are capable of differentiating into multiple cell types, including both myeloid and lymphoid cells. These pluripotent stem cells give rise to the more specialized myeloid and lymphoid stem cells, which then go on to differentiate into the various types of blood cells found in the body.
30.
In tissues, ------ are cells that develop into macrophages and are phagocytic
Correct Answer
monocytes
Explanation
Monocytes are a type of white blood cells that are produced in the bone marrow and circulate in the bloodstream. In tissues, monocytes can differentiate into macrophages, which are responsible for engulfing and destroying pathogens and cellular debris through a process called phagocytosis. Therefore, monocytes are the correct answer as they develop into macrophages and possess phagocytic abilities.
31.
Macrophage movement called ----- to the site of infection by a chemical stimulus
Correct Answer
chemotaxis
Explanation
Macrophages are immune cells that play a crucial role in the immune response against infections. When there is an infection, certain chemicals are released from the site of infection. These chemicals act as a stimulus for macrophages, attracting them towards the site of infection. This movement of macrophages towards the infection site is called chemotaxis. It allows macrophages to effectively locate and eliminate pathogens, contributing to the body's defense against infections.