2.
The _____ cells of the heart do not maintain stable resting membrane potentials; therefore they continually depolarize.
Explanation
The correct answer is "auto-rhythmic" and "autorhythmic". These terms refer to a specific type of cells in the heart that do not maintain a stable resting membrane potential. Instead, they continually depolarize, meaning that their electrical charge fluctuates, causing them to generate spontaneous action potentials. These auto-rhythmic/autorhythmic cells are responsible for initiating and coordinating the heartbeat, ensuring that the heart contracts rhythmically and regularly.
3.
The _____ are the simplest lymphoid organs and are found at the entrance to the pharynx.
Explanation
The tonsils are the simplest lymphoid organs and are found at the entrance to the pharynx. They play a crucial role in the immune system by trapping and filtering out bacteria and other harmful substances that enter the body through the mouth and nose. The tonsils also produce antibodies to fight off infections, helping to prevent the spread of pathogens in the body.
4.
The thoracic duct of the lymphatic system empties into the ______.
Explanation
The thoracic duct is the largest lymphatic vessel in the body and it is responsible for draining lymph from the lower body, left upper body, and the entire body above the diaphragm. It empties into the left subclavian vein, which is located near the collarbone. This is where the lymphatic system returns the lymph back into the bloodstream.
5.
Highly specialized lymph capillaries called ________ are present in the villi of the intestinal mucosa.
Explanation
Lacteals are highly specialized lymph capillaries that are present in the villi of the intestinal mucosa. These lacteals play a crucial role in the absorption of dietary fats. They are responsible for transporting the absorbed fats, known as chylomicrons, into the lymphatic system and eventually into the bloodstream. This allows for the efficient absorption and transportation of fats from the small intestine to other parts of the body.
6.
The ECG T wave interval represents _________.
Explanation
The ECG T wave interval represents ventricle repolarization. This is the phase of the cardiac cycle where the ventricles relax and reset their electrical charge after contraction. The T wave on an electrocardiogram (ECG) represents this repolarization process, indicating that the ventricles are preparing for the next contraction. Monitoring the T wave interval can provide valuable information about the electrical activity and health of the heart.
7.
The _______ valve of the heart has three valves with chordae tendineae.
Explanation
The tricuspid valve of the heart is located between the right atrium and right ventricle. It consists of three cusps or flaps, hence the name "tricuspid." These cusps are connected to the papillary muscles in the ventricle by chordae tendineae, which help to prevent the valve from prolapsing or leaking. The tricuspid valve ensures that blood flows in one direction, from the right atrium to the right ventricle, and prevents backflow.
8.
CO = ______ x SV.
Explanation
The equation CO = HR x SV represents the calculation of cardiac output (CO), which is the volume of blood pumped by the heart per minute. In this equation, HR refers to heart rate, which is the number of times the heart beats per minute. Therefore, the correct answer is HR (heart rate), heart rate, or simply HR.
9.
Arterial ________ provide alternate pathways for blood to get to an organ.
Explanation
Arterial anastomoses are connections between arteries that provide alternate pathways for blood to reach an organ. These connections allow for collateral circulation, which is important in cases where there is a blockage or restriction in one of the arteries supplying blood to an organ. By providing alternative routes, anastomoses ensure that the organ continues to receive an adequate blood supply, preventing damage or dysfunction.
10.
Harmful or disease-causing microorganisms are called _____.
Explanation
Harmful or disease-causing microorganisms are called pathogens. Pathogens are responsible for causing various infections and diseases in humans, animals, and plants. They can be bacteria, viruses, fungi, or parasites that invade the body and disrupt its normal functioning. Pathogens can spread through direct contact, contaminated food or water, or through vectors like mosquitoes and ticks. Understanding and studying pathogens is crucial in order to develop effective treatments and preventive measures against infectious diseases.
11.
The ______ pulp of the spleen forms cuffs around the central arteries.
Explanation
The white pulp of the spleen forms cuffs around the central arteries. This is because the white pulp is composed of lymphoid tissue, which contains immune cells such as lymphocytes. The central arteries are important for blood supply to the spleen, and the cuffs formed by the white pulp help to regulate and monitor the blood as it passes through the spleen. This allows the immune cells in the white pulp to interact with any pathogens or foreign substances present in the blood, helping to initiate an immune response if necessary.
12.
The ______ artery is a blood vessel on the arm used as a pressure point.
Explanation
The brachial artery is a blood vessel located in the arm that is commonly used as a pressure point. When pressure is applied to this artery, it can help control bleeding or assess blood flow. This artery is easily accessible and can be felt on the inside of the upper arm, making it a convenient location for medical professionals to use as a pressure point.
13.
_____ cells can lyse and kill cancer cells and virus-infected body cells before the immune system is activated.
Explanation
Natural killer (NK) cells are a type of lymphocyte that can recognize and kill cancer cells and virus-infected body cells. Unlike other immune cells, NK cells do not require prior activation by the immune system to initiate their killing function. They can directly identify and destroy abnormal cells through a process called lysis. NK cells play a crucial role in the early defense against cancer and viral infections, providing a rapid response before the adaptive immune system is fully activated.
14.
______ are grafts taken from another animal species.
Explanation
Xenographs are grafts taken from another animal species. They are used in medical research and transplantation procedures when the desired tissue or organ is not available from the same species. Xenographs can help scientists study the effects of diseases, test new drugs, and develop new treatments. However, the use of xenographs can also pose challenges such as immune rejection and ethical concerns.
15.
_______ becomes bound to mast cells and basophils and causes cells to release histamine and other chemicals.
Explanation
IgE is a type of antibody that becomes bound to mast cells and basophils. When IgE binds to these cells, it triggers them to release histamine and other chemicals. This release of histamine and other chemicals is responsible for allergic reactions, such as itching, sneezing, and swelling. IgE plays a crucial role in the immune response against parasites and is also involved in allergic responses.
16.
_______ refers to a group of at least 20 plasma proteins that normally circulate in an inactive state and are a major mechanism for destroying foreign substances in the body.
Explanation
Complement refers to a group of at least 20 plasma proteins that circulate in an inactive state. These proteins are an important part of the immune system and play a major role in destroying foreign substances in the body. When activated, complement proteins can enhance the ability of antibodies and phagocytic cells to eliminate pathogens and other foreign materials. Therefore, complement is a crucial mechanism for immune defense against infections and maintaining overall health.
17.
________ are released by activated T cells and macrophages to mobilize immune cells and attract other leukocytes into area.
Correct Answer
A. Cytokines
Explanation
Cytokines are signaling molecules that are released by activated T cells and macrophages. They play a crucial role in mobilizing immune cells and attracting other leukocytes into the affected area. By releasing cytokines, the immune system can coordinate and regulate the immune response, ensuring that the appropriate immune cells are recruited to the site of infection or inflammation. Cytokines also help in communication between immune cells and can modulate the immune response by promoting inflammation or regulating the activity of other immune cells. Thus, cytokines are essential for the proper functioning of the immune system.
18.
The thymus is most active during:
Correct Answer
A. Childhood.
Explanation
The thymus is an organ located in the chest that plays a crucial role in the development of the immune system. It is responsible for the production and maturation of T-cells, which are important for fighting off infections and diseases. The thymus is most active during childhood because this is the period when the immune system is still developing and maturing. As we age, the thymus gradually shrinks and becomes less active, which can lead to a decline in immune function. Therefore, childhood is the correct answer as it corresponds to the peak activity of the thymus.
19.
Particularly large clusters of lymph nodes occur in all of the following locations except the:
Correct Answer
A. Lower extremities.
Explanation
Particularly large clusters of lymph nodes occur in the inguinal region, cervical region, and axillary region. However, the lower extremities do not have particularly large clusters of lymph nodes. Lymph nodes are present throughout the body and play a crucial role in filtering lymph fluid and trapping pathogens. Inguinal lymph nodes are located in the groin area, cervical lymph nodes are found in the neck, and axillary lymph nodes are located in the armpit region. The lower extremities, which include the legs and feet, do not have large clusters of lymph nodes compared to these other regions.
20.
The P wave of a normal electrocardiogram indicates:
Correct Answer
A. Atrial depolarization.
Explanation
The P wave of a normal electrocardiogram indicates atrial depolarization. Depolarization refers to the electrical activation of the heart muscle, causing it to contract. In this case, the P wave represents the depolarization of the atria, which is the first step in the cardiac cycle. This electrical signal spreads through the atria, causing them to contract and pump blood into the ventricles. Therefore, the correct answer is atrial depolarization.
21.
Which of the following is associated with passive immunity?
Correct Answer
A. Passage of IgG antibodies from a pregnant mother to her fetus.
Explanation
Passive immunity refers to the transfer of pre-formed antibodies from one individual to another, providing immediate but temporary protection. The passage of IgG antibodies from a pregnant mother to her fetus is an example of passive immunity. During pregnancy, antibodies produced by the mother's immune system are transferred across the placenta to the fetus, offering protection against certain infections. This type of immunity is temporary and lasts only as long as the antibodies remain in the baby's system. Infusion of weakened viruses, long-term immune protection, and booster shots are associated with active immunity, where the individual's immune system produces its own antibodies in response to an infection or vaccination.
22.
The only t cells that can directly attack and kill other cells are the:
Correct Answer
A. Cytotoxic cells.
Explanation
Cytotoxic cells, also known as cytotoxic T cells or CD8+ T cells, are a type of T cell that can directly attack and kill other cells. They are able to recognize and bind to infected or abnormal cells, releasing toxic substances that induce cell death. This mechanism allows cytotoxic cells to play a crucial role in immune responses against viruses, cancer cells, and other intracellular pathogens. Plasma cells, helper cells, and suppressor cells do not possess this ability to directly attack and kill other cells.
23.
Select the correct statement about phagocytic cells.
Correct Answer
A. Neutrophils may destroy themselves when they phagocytize large quantities of a foreign substance.
Explanation
Neutrophils are a type of phagocytic cell that play a crucial role in the immune response. When neutrophils phagocytize large quantities of a foreign substance, they can undergo a process called "oxidative burst" or "respiratory burst." This burst involves the production of reactive oxygen species (ROS) such as superoxide radicals and hydrogen peroxide, which are used to kill and destroy the engulfed microorganisms. However, excessive ROS production can also lead to damage of the neutrophils themselves, causing them to undergo cell death. This phenomenon is known as "oxidative stress-induced apoptosis" and is a mechanism to prevent the spread of infection but can also contribute to tissue damage.
24.
Which of the following factors does NOT influence heart rate?
Correct Answer
A. Skin color.
Explanation
Skin color does not influence heart rate. Heart rate is primarily influenced by factors such as gender, body temperature, and age. Gender can have an impact on heart rate due to hormonal differences, body temperature can affect heart rate as the body tries to regulate its internal temperature, and heart rate tends to decrease with age. However, skin color does not have a direct influence on heart rate.
25.
Aldosterone will:
Correct Answer
A. Promote an increase in blood pressure.
Explanation
Aldosterone is a hormone produced by the adrenal glands that plays a role in regulating blood pressure. It acts on the kidneys to increase the reabsorption of sodium and water, which leads to an increase in blood volume. This increase in blood volume ultimately results in an increase in blood pressure. Therefore, the correct answer is that aldosterone promotes an increase in blood pressure.
26.
Small organs associated with lymphatic vessels are termed:
Correct Answer
A. Lymph nodes.
Explanation
Lymph nodes are small organs that are associated with lymphatic vessels. These nodes play a crucial role in the immune system by filtering lymph and trapping harmful substances such as bacteria and viruses. They contain immune cells that help in the production of antibodies and the activation of immune responses. Lymph follicles, axillary nodes, and cisterna chyli are not the correct terms for small organs associated with lymphatic vessels.
27.
Which of the following i not a function of the inflammatory response?
Correct Answer
A. Replaces injured tissues with connective tissue.
Explanation
The inflammatory response is a natural defense mechanism of the body that occurs in response to tissue injury or infection. It involves a series of events aimed at eliminating the harmful agent and initiating the healing process. The functions of the inflammatory response include preventing the spread of the injurious agent to nearby tissues, disposing of cellular debris and pathogens, and setting the stage for the repair process. However, replacing injured tissues with connective tissue is not a function of the inflammatory response. This process is typically carried out by the process of tissue repair, which occurs after the inflammatory response has subsided.
28.
Small molecules that bind with self-proteins to produce antigenic substances are called:
Correct Answer
A. Haptens.
Explanation
Haptens are small molecules that can bind to self-proteins and form antigenic substances. These substances can then trigger an immune response in the body. Reagins are antibodies associated with allergic reactions, ions are charged particles, and antibodies are proteins produced by the immune system to target specific antigens. Therefore, haptens are the correct answer as they specifically refer to small molecules that bind with self-proteins to produce antigenic substances.
29.
The ligamentum arteriosum connects the?
Correct Answer
A. Pulmonary trunk and the arch of the aorta.
Explanation
The ligamentum arteriosum is a small fibrous band that connects the pulmonary trunk to the arch of the aorta. During fetal development, it is a vital structure that diverts blood away from the lungs and towards the systemic circulation. However, after birth, the ligamentum arteriosum typically undergoes fibrosis and becomes non-functional. So, the correct answer is the pulmonary trunk and the arch of the aorta.
30.
A rapid heart beat of over 100 beats per minute is called?
Correct Answer
A. Tachycardia.
Explanation
Tachycardia refers to a rapid heart rate of over 100 beats per minute. It is a condition where the heart beats faster than normal, which can be caused by various factors such as stress, exercise, or certain medical conditions. Flutter and fibrillation are also abnormal heart rhythms, but they refer to specific patterns of irregular heartbeats. Bradycardia, on the other hand, is a slow heart rate, which is the opposite of tachycardia. Therefore, the correct answer is tachycardia.
31.
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is:
Correct Answer
A. Angina pectoris.
Explanation
Angina pectoris is the correct answer because it refers to the pain associated with inadequate blood supply to the heart muscle. This condition is often caused by the temporary narrowing or spasm of the coronary arteries, which restricts blood flow to the heart. Angina pectoris is characterized by chest pain or discomfort, which can radiate to the arms, shoulders, neck, jaw, or back. It is usually triggered by physical exertion or emotional stress and is relieved by rest or medication. Myocardial infarct refers to a heart attack, pericarditis is inflammation of the pericardium, and ischemia is a general term for inadequate blood supply to an organ or tissue.
32.
Which tunic of an artery is most responsible for maintaining blood pressure and continuous blood circulation?
Correct Answer
A. Tunica media.
Explanation
The tunica media of an artery is composed of smooth muscle cells and elastic fibers, which allows it to contract and relax, thus regulating the diameter of the artery. This ability to constrict and dilate is what enables the tunica media to maintain blood pressure and control blood flow. The tunica adventitia provides structural support to the artery, while the tunica interna (intima) forms the inner lining. The tunica externa is the outermost layer of the artery.
33.
Which of the following is NOT characteristic of the adaptive immune system?
Correct Answer
A. It is specific for a given organ.
Explanation
The adaptive immune system is not specific for a given organ. It is a systemic response that can act throughout the entire body. This is in contrast to the innate immune system, which provides a more generalized defense against pathogens. The adaptive immune system is antigen-specific, meaning it can recognize and target specific pathogens or foreign substances. It also has memory, allowing it to mount a faster and more effective response upon subsequent exposure to the same pathogen.
34.
The chief antibody-mediated mechanism used against cellular antigens such as bacteria is:
Correct Answer
A. Complement fixation.
Explanation
Complement fixation is the correct answer because it is a chief antibody-mediated mechanism used against cellular antigens such as bacteria. Complement fixation involves the activation of the complement system, which leads to the formation of membrane attack complexes that can lyse the bacterial cells. This mechanism is an important part of the immune response against bacterial infections. Agglutination, interferon production, and neutralization are also immune responses, but they are not specifically targeted against cellular antigens like bacteria.
35.
Which statement best describes arteries?
Correct Answer
A. All carry blood away from the heart.
Explanation
Arteries are blood vessels that carry blood away from the heart. They are responsible for transporting oxygenated blood to various parts of the body. Unlike veins, arteries do not contain valves to prevent the back-flow of blood. The statement "All carry blood away from the heart" accurately describes the function of arteries.
36.
Select the correct definition about tissue grafts.
Correct Answer
A. Isografts are between identical twins.
Explanation
Isografts are tissue grafts that are transferred between identical twins. Identical twins have the same genetic makeup, so their tissues are compatible and do not elicit an immune response when transplanted. This makes isografts the most successful type of graft, with a high chance of acceptance and long-term survival. Autografts, on the other hand, involve transferring tissue from one part of an individual's body to another. Allografts are between individuals of the same species but with different genetic makeup, while xenografts are between different species.
37.
B lymphocytes develop immuno-competence in the:
Correct Answer
A. Bone marrow.
Explanation
B lymphocytes, also known as B cells, are a type of white blood cell that plays a crucial role in the immune response. They are responsible for producing antibodies that help in fighting against pathogens. The development of B lymphocytes occurs in the bone marrow. In the bone marrow, hematopoietic stem cells differentiate into B cells and undergo a series of maturation steps to become immunocompetent. This process involves the rearrangement of genes that encode for antibody production, ensuring that each B cell is capable of recognizing a specific antigen. Therefore, the correct answer is bone marrow.
38.
Blood flow to the skin:
Correct Answer
A. Increases when environmental temperature rises.
Explanation
When the environmental temperature rises, the body's blood vessels in the skin dilate or expand. This allows more blood to flow to the skin, which helps to dissipate heat and regulate body temperature. This increased blood flow to the skin helps to cool the body down and prevent overheating.
39.
Which tunic of an artery contains endothelium?
Correct Answer
A. Tunica interna (intima).
Explanation
The correct answer is Tunica interna (intima). The tunica interna, also known as the intima, is the innermost layer of an artery. It is composed of endothelial cells, which form a smooth lining that allows for the smooth flow of blood through the artery. The tunica interna also contains a layer of connective tissue and a layer of elastic fibers, which help to provide structural support to the artery.
40.
Blood within the pulmonary veins returns to the:
Correct Answer
A. Left atrium.
Explanation
The correct answer is left atrium because the pulmonary veins carry oxygenated blood from the lungs back to the heart. This oxygenated blood enters the left atrium, which then contracts to pump the blood into the left ventricle. From the left ventricle, the blood is then pumped out to the rest of the body through the aorta.
41.
Cancer cells and virus-infected body cells can be killed before activation of the immune system by:
Correct Answer
A. Natural killer cells.
Explanation
Natural killer cells are a type of white blood cell that can recognize and kill cancer cells and virus-infected cells without the need for activation by the immune system. Unlike T lymphocytes and B lymphocytes, which require prior activation to target specific antigens, natural killer cells have the ability to directly recognize and destroy abnormal cells. They do this by releasing toxic substances that induce cell death in their targets. Therefore, natural killer cells are responsible for eliminating these abnormal cells before the immune system is activated.
42.
Graft rejection may be caused by:
Correct Answer
A. Using a xenograft.
Explanation
Graft rejection occurs when the immune system recognizes the transplanted tissue as foreign and attacks it. Using a xenograft, which involves transplanting tissue from a different species, can trigger a strong immune response due to the significant differences in antigens between species. The immune system recognizes these foreign antigens and mounts a rejection response, leading to graft failure. This is why using a xenograft can cause graft rejection.
43.
Innate immune system defenses include:
Correct Answer
A. Phagocytosis.
Explanation
The correct answer is Phagocytosis. Phagocytosis is a process in which certain cells of the immune system, such as macrophages and neutrophils, engulf and destroy foreign particles, pathogens, and cellular debris. This is an important defense mechanism of the innate immune system that helps to eliminate potential threats and maintain overall immune function. B cells, T cells, and plasma cells are components of the adaptive immune system, which is not mentioned in the question.
44.
Cardiac output is about _______ L/min.
Explanation
Cardiac output refers to the amount of blood pumped by the heart per minute. The given answer of 5.25 L/min suggests that the average cardiac output is approximately 5.25 liters of blood per minute. This value represents the typical amount of blood circulated by the heart in a minute, indicating the efficiency of the heart's pumping action.
45.
Interferons:
Correct Answer
A. Interfere with viral replication within cells.
Explanation
Interferons are proteins that are produced by cells in response to viral infections. They play a crucial role in the immune response against viruses by interfering with viral replication within cells. This means that interferons inhibit the ability of viruses to reproduce and spread within the body, thereby limiting the severity and duration of the infection. Interferons are not virus-specific, meaning that they can have antiviral effects against a broad range of viruses. Therefore, an interferon produced against one virus can protect cells against other viruses as well. Increasing the rate of cell division is not a mechanism of action for interferons.
46.
Which of the following would be classified a delayed hypersensitivity reaction?
Correct Answer
A. Allergic contact dermatitis.
Explanation
Allergic contact dermatitis is classified as a delayed hypersensitivity reaction because it occurs a few hours to days after exposure to an allergen. This type of reaction involves the activation of T cells, which release inflammatory mediators and recruit other immune cells to the site of contact. In contrast, cytotoxic hypersensitivity involves the destruction of target cells by antibodies and immune complex hypersensitivity involves the formation of immune complexes that deposit in tissues and activate inflammation. Anaphylaxis is an immediate hypersensitivity reaction that occurs within minutes of exposure to an allergen.
47.
A thrombus (blood clot) in the first branch of the arch of the aorta would affect the flow of blood to the:
Correct Answer
A. Right side of the head and neck and right upper arm.
Explanation
A thrombus in the first branch of the arch of the aorta would affect the flow of blood to the right side of the head and neck and right upper arm. This is because the first branch of the arch of the aorta is the brachiocephalic trunk, which gives rise to the right common carotid artery and the right subclavian artery. These arteries supply blood to the right side of the head, neck, and upper arm. Therefore, a blood clot in this location would obstruct the flow of blood to these areas.
48.
Which of the following is a type of circulatory shock?
Correct Answer
A. Vascular due to extreme vasodilation as a result of loss of vasomotor tone.
Explanation
The correct answer is "Vascular due to extreme vasodilation as a result of loss of vasomotor tone." This type of circulatory shock occurs when there is a loss of vasomotor tone, which leads to extreme vasodilation of blood vessels. This causes a decrease in blood pressure and inadequate blood flow to organs and tissues, resulting in shock.
49.
In what specific area of the chest is the heart found?
Correct Answer
A. Mediastinum.
Explanation
The heart is found in the mediastinum, which is the central compartment of the thoracic cavity. It is located between the lungs and extends from the sternum in front to the vertebral column behind. The mediastinum contains various structures including the heart, great vessels, esophagus, trachea, and thymus.