Professor Tate's Test 2: Ch 18-21
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Practice test for Professor Tate's final anatomy & physiology exam. Questions taken from 2nd test of the semester. Chapters 18-21.
- 1.
The lymphatic capillaries are:
- A.
Equally permeable to blood capillaries.
- B.
Completely impermeable.
- C.
Less permeable than blood capillaries.
- D.
More permeable than blood capillaries.
Correct Answer
D. More permeable than blood capillaries.Explanation
The lymphatic capillaries are more permeable than blood capillaries. This is because the lymphatic capillaries have larger openings between their endothelial cells, allowing for the easy entry of interstitial fluid, proteins, and other large molecules. In contrast, blood capillaries have tighter junctions between their endothelial cells, restricting the movement of larger molecules. The increased permeability of lymphatic capillaries allows them to collect excess fluid and waste products from the tissues and transport them back to the bloodstream.Rate this question:
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- 2.
The only immunoglobulin to exist as a pentamer is:
- A.
IgA.
- B.
IgG.
- C.
IgM.
- D.
IgD.
Correct Answer
C. IgM.Explanation
IgM is the only immunoglobulin that exists as a pentamer. It is the first antibody produced during an immune response and is mainly found in the bloodstream. The pentameric structure of IgM allows it to efficiently bind to antigens and activate the complement system, which helps in the clearance of pathogens. Other immunoglobulins, such as IgA, IgG, and IgD, exist in different forms, such as monomers or dimers, but not as pentamers. Therefore, IgM is the correct answer.Rate this question:
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- 3.
Which of the following is not an autoimmune disease?
- A.
Systemic lupus erythematosus.
- B.
Multiple sclerosis.
- C.
Glomerulonephritis.
- D.
Type II diabetes.
Correct Answer
D. Type II diabetes.Explanation
Type II diabetes is not considered an autoimmune disease. Autoimmune diseases occur when the immune system mistakenly attacks healthy cells and tissues in the body. In contrast, Type II diabetes is a metabolic disorder that occurs when the body becomes resistant to insulin or does not produce enough insulin to regulate blood sugar levels. While there may be some immune system involvement in the development of Type II diabetes, it is not primarily caused by autoimmunity.Rate this question:
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- 4.
Noreprinephrine acts on heart muscle cells by:
- A.
Decreasing heart contractility.
- B.
Blocking the action of calcium.
- C.
Causing threshold to be reached more quickly.
- D.
Causing a decrease in stroke volume.
Correct Answer
C. Causing threshold to be reached more quickly.Explanation
Norepinephrine acts on heart muscle cells by causing the threshold to be reached more quickly. This means that it increases the excitability of the heart cells, making them more likely to initiate an action potential and contract. This can lead to an increase in heart rate and cardiac output.Rate this question:
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- 5.
Complement proteins and antibodies coat a microorganism and roughen its surface, Enabling macrophages and neutrophils to phagocytize the organism. This phenomenon is termed:
- A.
Diapedesis.
- B.
Opsonization.
- C.
Agglutination.
- D.
Chemotaxis.
Correct Answer
B. Opsonization.Explanation
Opsonization is the process in which complement proteins and antibodies bind to the surface of a microorganism, making it easier for macrophages and neutrophils to recognize and engulf the organism through phagocytosis. This coating roughens the surface of the microorganism, enhancing its recognition by immune cells. Diapedesis refers to the process of immune cells squeezing through blood vessel walls to reach the site of infection. Agglutination refers to the clumping together of microorganisms by antibodies. Chemotaxis refers to the movement of immune cells towards a chemical signal.Rate this question:
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- 6.
Suppressor T cells:
- A.
Decrease their activity as antigenic stimulus decreases.
- B.
May function in preventing autoimmune reactions.
- C.
Are the most thoroughly understood T cells.
- D.
Release cytokines that increase the activity of cytotoxic T cells and activated B cells.
Correct Answer
B. May function in preventing autoimmune reactions.Explanation
Suppressor T cells, also known as regulatory T cells, are a subset of T cells that play a crucial role in maintaining immune tolerance and preventing autoimmune reactions. These cells suppress the activity of other immune cells, such as cytotoxic T cells and activated B cells, to prevent excessive immune responses that could lead to the destruction of healthy tissues. Therefore, the statement "May function in preventing autoimmune reactions" accurately describes the role of suppressor T cells in the immune system.Rate this question:
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- 7.
Which of the following is a part of the second line of defense against microorganisms?
- A.
Keratin.
- B.
Ciia.
- C.
Gastric juice.
- D.
Phagocytes.
Correct Answer
D. pHagocytes.Explanation
Phagocytes are a part of the second line of defense against microorganisms. Phagocytes are a type of white blood cell that can engulf and destroy foreign particles, including microorganisms. They are an important component of the immune system and play a crucial role in protecting the body against infections. Keratin is a structural protein found in the skin, hair, and nails and does not directly participate in the immune response. Ciia is not a recognized term or component of the immune system. Gastric juice is a part of the first line of defense as it contains acid that helps to kill ingested microorganisms in the stomach.Rate this question:
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- 8.
Aldosterone will:
- A.
Decrease sodium resorption.
- B.
Promote an increase in blood pressure.
- C.
Result in a larger output of urine.
- D.
Promote a decrease in blood volume.
Correct Answer
B. 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.Rate this question:
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- 9.
Select the correct statement about the movement of materials at the capillary level.
- A.
If the osmotic pressure in the blood vessels is relatively higher than that in the tissues, tissue edema will result.
- B.
Chemical waste products follow the same general path as oxygen.
- C.
Oxygen diffuses up its concentration gradient.
- D.
Carbon dioxide moves from its production site into the interstitial fluid.
Correct Answer
D. Carbon dioxide moves from its production site into the interstitial fluid.Explanation
Carbon dioxide is a waste product produced by cells during cellular respiration. It moves from its production site in the cells into the interstitial fluid, which is the fluid that surrounds the cells. From there, it can diffuse into the blood vessels and be transported to the lungs for elimination. This movement of carbon dioxide helps to maintain the balance of gases in the body and remove waste products.Rate this question:
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- 10.
Toll-like receptors (TLRs) trigger the release of ______ to attract white blood cells to the scene.
- A.
Complement.
- B.
Prostaglandins.
- C.
Cytokines.
- D.
Histamine.
Correct Answer
C. Cytokines.Explanation
TLRs are a type of protein receptors that play a crucial role in the immune response. When TLRs are activated by the presence of pathogens, they trigger the release of cytokines. Cytokines are small proteins that act as signaling molecules, communicating between cells and coordinating the immune response. In this case, the release of cytokines helps to attract white blood cells to the site of infection or inflammation, where they can eliminate the pathogens and promote tissue repair. Complement, prostaglandins, and histamine are also involved in the immune response, but they do not specifically attract white blood cells like cytokines do.Rate this question:
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- 11.
The term blood islands refers to:
- A.
Areas of the vascular system where blood does not circulate.
- B.
The areas of the pancreas where insulin is produced.
- C.
Embryonic masses of mesodermal cells that give rise to the endothelial lining of blood vessels.
- D.
The regions of the liver where nutrients are extracted from visceral blood.
Correct Answer
C. Embryonic masses of mesodermal cells that give rise to the endothelial lining of blood vessels.Explanation
The term "blood islands" refers to embryonic masses of mesodermal cells that give rise to the endothelial lining of blood vessels. During embryonic development, these clusters of cells differentiate and form the basis for the future blood vessels in the body. They play a crucial role in the formation and development of the vascular system. This explanation is supported by the understanding of embryology and the process of blood vessel formation.Rate this question:
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- 12.
The system that recognizes foreign molecules and acts to immobilize, neutralize, or destroy them is the:
- A.
Lymphatic system.
- B.
Renal system.
- C.
Immune system.
- D.
Integumentary system.
Correct Answer
C. Immune system.Explanation
The immune system is responsible for recognizing foreign molecules, such as pathogens or toxins, and taking action to neutralize or destroy them. It is composed of various cells, tissues, and organs that work together to provide immunity and protect the body from infections and diseases. The lymphatic system, renal system, and integumentary system have their own specific functions but do not play the same role as the immune system in recognizing and responding to foreign molecules.Rate this question:
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- 13.
Cardiac output is about _______ L/min.
- A.
4.25
- B.
7.27
- C.
5.25
- D.
6.26
Correct Answer
C. 5.25Explanation
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.Rate this question:
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- 14.
Small molecules that bind with self-proteins to produce antigenic substances are called:
- A.
Haptens.
- B.
Reagins.
- C.
Ions.
- D.
Antibodies.
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.Rate this question:
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- 15.
The ligamentum arteriosum connects the?
- A.
The superior vena cava and the ascending aorta.
- B.
Pulmonary trunk and the arch of the aorta.
- C.
Pulmonary veins and the arch of the aorta.
- D.
The ascending aorta and the right pulmonary artery.
Correct Answer
B. 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.Rate this question:
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- 16.
Which of the following is not a blood vessel attached to the circle of Willis?
- A.
Anterior cerebral artery.
- B.
Posterior cerebral artery.
- C.
Anterior communicating artery.
- D.
Posterior communicating artery.
Correct Answer
B. Posterior cerebral artery.Explanation
The circle of Willis is a circular network of blood vessels at the base of the brain that helps to supply blood to the brain. It is formed by the anterior cerebral artery, the posterior cerebral artery, the anterior communicating artery, and the posterior communicating artery. The correct answer is the posterior cerebral artery because it is indeed a blood vessel attached to the circle of Willis.Rate this question:
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- 17.
_______ predominate at the site of chronic infections.
- A.
Basophils
- B.
B cells
- C.
Eosinophils
- D.
Macrophages
Correct Answer
D. MacropHagesExplanation
Macrophages predominate at the site of chronic infections because they are specialized immune cells that play a crucial role in the immune response against pathogens. They are capable of engulfing and destroying foreign invaders, such as bacteria and viruses, through a process called phagocytosis. Macrophages also release various chemical signals to recruit other immune cells and enhance the immune response. In chronic infections, macrophages are often found in high numbers at the site of infection, where they persistently work to eliminate the pathogen and resolve the infection. Therefore, macrophages are the correct answer for this question.Rate this question:
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- 18.
Which of the following is characteristic of complete antigens?
- A.
Inhibit production of antibodies.
- B.
Small molecules.
- C.
Reactivity with an antibody.
- D.
Contain many repeating chemical units.
Correct Answer
C. Reactivity with an antibody.Explanation
Complete antigens are molecules that can stimulate an immune response and react with specific antibodies. This means that they have the ability to bind to antibodies and trigger an immune response. In contrast, antigens that inhibit production of antibodies or are small molecules may not have the ability to elicit a strong immune response. Additionally, complete antigens are often large molecules that contain many repeating chemical units, which can enhance their immunogenicity.Rate this question:
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- 19.
The form of circulatory shock known as hypovolemic shock is:
- A.
Any condition in which blood vessels are inadequately filled and blood cannot circulate normally.
- B.
Only that form of shock caused by large-scale loss of blood.
- C.
Always fatal.
- D.
Shock that results from large-scale loss of blood volume or after severe vomiting or diarrhea.
Correct Answer
D. Shock that results from large-scale loss of blood volume or after severe vomiting or diarrhea.Explanation
Hypovolemic shock is a form of circulatory shock that occurs when there is a significant loss of blood volume or fluid due to events such as severe bleeding, vomiting, or diarrhea. This loss of blood or fluid leads to inadequate filling of blood vessels, resulting in impaired circulation. It is not the only form of shock caused by large-scale blood loss, but it is one of the causes. While hypovolemic shock can be life-threatening, it is not always fatal and can be treated with prompt medical intervention.Rate this question:
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- 20.
The circulatory route that runs from the digestive tract to the liver is called:
- A.
Pulmonary circulation.
- B.
Coronary circulation.
- C.
Cerebral circulation.
- D.
Hepatic portal circulation.
Correct Answer
D. Hepatic portal circulation.Explanation
Hepatic portal circulation refers to the circulatory route that runs from the digestive tract to the liver. This specialized system allows the nutrients and toxins absorbed from the intestines to be processed and metabolized by the liver before being distributed to the rest of the body. It plays a crucial role in regulating blood sugar levels, detoxification, and nutrient storage. Pulmonary circulation refers to the flow of blood between the heart and the lungs, coronary circulation refers to the blood flow within the heart muscle, and cerebral circulation refers to the blood supply to the brain.Rate this question:
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- 21.
Which of the following is likely during vigorous exercise?
- A.
The skin will be cold and clammy.
- B.
Blood will be diverted to the digestive organs.
- C.
Capillaries of the active muscles will be engorged with blood.
- D.
Blood flow to the kidneys increases.
Correct Answer
C. Capillaries of the active muscles will be engorged with blood.Explanation
During vigorous exercise, the body requires more oxygen and nutrients to be delivered to the active muscles. To meet this demand, the capillaries of the active muscles will dilate and become engorged with blood. This allows for increased blood flow to the muscles, delivering the necessary oxygen and nutrients and removing waste products such as carbon dioxide. This increased blood flow helps to support the increased energy demands of the muscles during exercise.Rate this question:
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- 22.
The left coronary artery branches into the anterior interventricular and _____ arteries.
- A.
Great cardiac arteries
- B.
Circumflex
- C.
Marginal
- D.
Posterior interventricular
Correct Answer
B. CircumflexExplanation
The left coronary artery branches into the anterior interventricular and circumflex arteries. The anterior interventricular artery supplies blood to the anterior walls of both ventricles, while the circumflex artery wraps around the heart and supplies blood to the left atrium and the posterior walls of the left ventricle. This branching pattern ensures adequate blood supply to the various regions of the heart.Rate this question:
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- 23.
A rapid heart beat of over 100 beats per minute is called?
- A.
Tachycardia.
- B.
Flutter.
- C.
Fibrillation.
- D.
Bradycardia.
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.Rate this question:
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- 24.
The primary immune response:
- A.
Occurs more rapidly and is stronger than the secondary response.
- B.
Occurs when memory cells are stimulated.
- C.
Has a lag period whole B cells proliferate and differentiate into plasma cells.
- D.
Is another name for immunological memory.
Correct Answer
C. Has a lag period whole B cells proliferate and differentiate into plasma cells.Explanation
The primary immune response refers to the initial response of the immune system to an antigen. It takes time for the immune system to recognize and respond to the antigen, which results in a lag period. During this lag period, B cells, a type of white blood cell, undergo proliferation and differentiation into plasma cells. These plasma cells then produce and release antibodies specific to the antigen, leading to the immune response. The primary immune response is not as rapid or strong as the secondary response, which occurs upon re-exposure to the same antigen and involves memory cells. Immunological memory refers to the ability of the immune system to remember and respond more effectively to previously encountered antigens.Rate this question:
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- 25.
Select the correct statement about phagocytic cells.
- A.
Neutrophils may destroy themselves when they phagocytize large quantities of a foreign substance.
- B.
Kupffer cells are a type of neutrophil.
- C.
Macrophages release defensins during killing.
- D.
The respiratory burst characterizes eosinophil phagocytosis.
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.Rate this question:
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- 26.
The pulse pressure is:
- A.
Systolic pressure plus diastolic pressure.
- B.
Systolic pressure minus diastolic pressure.
- C.
Diastolic pressure plus 1/3 (systolic pressure plus diastolic pressure).
- D.
Systolic pressure divided by diastolic pressure.
Correct Answer
D. Systolic pressure divided by diastolic pressure. -
- 27.
Which of the following would not be classified as a lymphatic structure?
- A.
Spleen.
- B.
Peyer's Patches of the intestine.
- C.
Pancreas.
- D.
Tonsils.
Correct Answer
C. Pancreas.Explanation
The pancreas would not be classified as a lymphatic structure because it is primarily an organ of the digestive system, involved in producing digestive enzymes and hormones such as insulin. Lymphatic structures are organs or tissues that are part of the lymphatic system, which is responsible for producing and transporting lymphocytes and other immune cells. The spleen, Peyer's patches of the intestine, and tonsils are all examples of lymphatic structures because they play a role in filtering and trapping pathogens, producing lymphocytes, and initiating immune responses.Rate this question:
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- 28.
Graft rejection may be caused by:
- A.
Total body irradiation.
- B.
Using a xenograft.
- C.
Use of immuno-suppressive drugs.
- D.
Treatment with anti-lymphocyte serum.
Correct Answer
B. 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.Rate this question:
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- 29.
Select the correct statement about the function of myocardial cells.
- A.
The refractory period in skeletal muscle is much longer than that in cardiac muscle.
- B.
The influx of potassium ions from extracellular sources is the initiating event in cardiac muscle contraction.
- C.
The all-or-none law as applied to cardiac muscle means that the entire heart contracts as a unit or it doesn't contract at all.
- D.
Cardiac muscle cells are each innervated by a sympathetic nerve ending so that the nervous system can increase heart rate.
Correct Answer
C. The all-or-none law as applied to cardiac muscle means that the entire heart contracts as a unit or it doesn't contract at all.Explanation
The all-or-none law states that when a cardiac muscle cell is stimulated, it will contract to its maximum strength or not at all. This means that all the cells in the heart contract together, resulting in a synchronized contraction of the entire heart. This is essential for the heart to effectively pump blood and maintain its function as a unit.Rate this question:
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- 30.
Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of:
- A.
Arteries.
- B.
Arterioles.
- C.
Veins.
- D.
Capillaries.
Correct Answer
D. Capillaries.Explanation
Capillaries are tiny blood vessels that connect arteries and veins. They have thin walls which allow for the exchange of nutrients and gases between the blood and tissue cells. This is possible due to their close proximity to the cells and their large surface area. Arteries carry oxygenated blood away from the heart, arterioles are smaller branches of arteries, and veins carry deoxygenated blood back to the heart. While all of these blood vessels play important roles in the circulatory system, the primary function of capillaries is to permit the exchange of nutrients and gases with the tissue cells.Rate this question:
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- 31.
B lymphocytes develop immuno-competence in the:
- A.
Thymus.
- B.
Bone marrow.
- C.
Spleen.
- D.
Lymph nodes.
Correct Answer
B. 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.Rate this question:
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- 32.
This blood vessel becomes the dorsalis pedis:
- A.
Fibular.
- B.
Posterior tibial.
- C.
Popliteal.
- D.
Femural.
- E.
Anterior tibial.
Correct Answer
E. Anterior tibial.Explanation
The correct answer is Anterior tibial because the dorsalis pedis is a major artery in the foot that supplies blood to the dorsal surface of the foot. The anterior tibial artery is a branch of the popliteal artery and becomes the dorsalis pedis artery as it passes through the ankle joint. Therefore, the anterior tibial artery is the blood vessel that becomes the dorsalis pedis.Rate this question:
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- 33.
Blood flow to the skin:
- A.
Increases when environmental temperature rises.
- B.
Is not an important source of nutrients and oxygen for skin cells.
- C.
Increases when body temperature drops so that the skin does not freeze.
- D.
Is controlled mainly by decreasing pH.
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.Rate this question:
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- 34.
Small organs associated with lymphatic vessels are termed:
- A.
Lymph nodes.
- B.
Lymph follicles.
- C.
Axillary nodes.
- D.
Cisterna chyli.
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.Rate this question:
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- 35.
Particularly large clusters of lymph nodes occur in all of the following locations except the:
- A.
Inguinal region.
- B.
Lower extremities.
- C.
Cervical region.
- D.
Axillary region.
Correct Answer
B. 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.Rate this question:
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- 36.
Which of the following is true about veins?
- A.
Venous valves are formed from the tunica media.
- B.
Veins have a small lumen in relation to the thickness of the vessel wall.
- C.
Up to 35% of total body blood is in venous circulation at any given time.
- D.
Veins are called capacitance vessels or blood reservoirs.
Correct Answer
D. Veins are called capacitance vessels or blood reservoirs.Explanation
Veins are called capacitance vessels or blood reservoirs because they have the ability to stretch and hold a large amount of blood. This allows veins to store blood and act as a reservoir, which can be quickly released when needed, such as during exercise or in times of low blood pressure. Veins also have valves, but they are not formed from the tunica media. The statement about the lumen size in relation to the thickness of the vessel wall is not mentioned in the explanation.Rate this question:
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- 37.
The P wave of a normal electrocardiogram indicates:
- A.
Atrial repolarization.
- B.
Atrial depolarization.
- C.
Ventricular depolarization.
- D.
Ventricular repolarization.
Correct Answer
B. 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.Rate this question:
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- 38.
Which of the statements is true about T cells?
- A.
They usually directly recognize antigens which then activates a sub population of killer cells.
- B.
Once activated they cannot secrete cytokines.
- C.
Their proliferation is enhanced by interleukins 1 and 2.
- D.
They will develop into cytotoxic T cells if antigen is complexed with class II MHC proteins.
Correct Answer
D. They will develop into cytotoxic T cells if antigen is complexed with class II MHC proteins.Explanation
T cells will develop into cytotoxic T cells if the antigen is complexed with class II MHC proteins. This statement suggests that T cells require the presence of class II MHC proteins in order to differentiate into cytotoxic T cells. Class II MHC proteins are typically found on the surface of antigen-presenting cells, and when they present antigens to T cells, it triggers the development of cytotoxic T cells. This process is important for the immune response, as cytotoxic T cells play a crucial role in eliminating infected or abnormal cells.Rate this question:
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- 39.
________ are released by activated T cells and macrophages to mobilize immune cells and attract other leukocytes into area.
- A.
Cytokines
- B.
Interleukin 1 proteins
- C.
Interleukin 2 proteins
- D.
Perforins
Correct Answer
A. CytokinesExplanation
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.Rate this question:
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- 40.
Which tunic of an artery contains endothelium?
- A.
Tunica interna (intima).
- B.
Tunica adventitia.
- C.
Tunica media.
- D.
Tunica externa.
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.Rate this question:
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- 41.
Which of the following is characteristic of antibodies?
- A.
Carbohydrate structure.
- B.
Composed of heavy and light polypeptide chains.
- C.
Incapable of being transferred from one person to another.
- D.
Three binding sites per antibody monomer.
Correct Answer
B. Composed of heavy and light polypeptide chains.Explanation
Antibodies are composed of heavy and light polypeptide chains. This is a characteristic feature of antibodies, as they are made up of two types of protein chains. The heavy chains are larger and provide structural stability, while the light chains are smaller and contribute to antigen binding. This composition allows antibodies to recognize and bind to specific antigens, marking them for destruction by the immune system. The presence of both heavy and light chains is essential for the proper functioning of antibodies in the immune response.Rate this question:
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- 42.
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells:
- A.
It would be less than 1-2ms.
- B.
Contractions would last as long as the refractory period.
- C.
Tetanic contractions might occur which would stoop the heart's pumping action.
- D.
It would be much longer before cardiac cells could respond to a second stimulation.
Correct Answer
C. Tetanic contractions might occur which would stoop the heart's pumping action.Explanation
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells, tetanic contractions might occur which would stop the heart's pumping action. Tetanic contractions refer to sustained, continuous contractions without any relaxation in between. In skeletal muscle cells, the refractory period is shorter, allowing for rapid contractions. However, in cardiac muscle cells, a longer refractory period is necessary to prevent tetanic contractions and ensure proper pumping of the heart. If the refractory period in cardiac cells was shortened to match that of skeletal muscle cells, it could lead to tetanic contractions, disrupting the heart's pumping action.Rate this question:
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- 43.
Which lymphatic structure drains lymph from the right upper limb and the right side of the head and thorax?
- A.
Thoracic duct.
- B.
Lumbar trunk.
- C.
Right lymphatic duct.
- D.
Cisterna chyli.
Correct Answer
C. Right lympHatic duct.Explanation
The right lymphatic duct drains lymph from the right upper limb and the right side of the head and thorax. The thoracic duct drains lymph from the rest of the body except for the right upper limb and right side of the head and thorax. The lumbar trunk and cisterna chyli are not directly involved in draining lymph from the right upper limb and right side of the head and thorax. Therefore, the correct answer is the right lymphatic duct.Rate this question:
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- 44.
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is:
- A.
Angina pectoris.
- B.
Myocardial infarct.
- C.
Pericarditis.
- D.
Ischemia.
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.Rate this question:
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- 45.
Cardiac reserve:
- A.
Can be determined by auscultation.
- B.
Is unrelated to health.
- C.
Can be improved by regular exercise.
- D.
Is determined by your genes and not subject to improvement.
Correct Answer
C. Can be improved by regular exercise.Explanation
Cardiac reserve refers to the ability of the heart to increase its output in response to increased demands, such as during exercise. Regular exercise improves cardiac reserve by strengthening the heart muscle, improving its efficiency, and increasing its capacity to pump blood. This leads to a lower resting heart rate, increased stroke volume, and improved overall cardiovascular fitness. Therefore, regular exercise is essential for improving cardiac reserve and overall heart health.Rate this question:
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- 46.
The velocity of blood flow:
- A.
Is in direct proportion to the total cross-sectional area of the blood vessels.
- B.
Is slower in the veins than in the capillaries since veins have a large diameter.
- C.
Is slower in the arteries than capillaries since they possess a relatively large diameter.
- D.
Is slowest in the capillaries since the total cross-sectional area is the greatest.
Correct Answer
D. Is slowest in the capillaries since the total cross-sectional area is the greatest.Explanation
The velocity of blood flow is slowest in the capillaries because the total cross-sectional area is the greatest. This means that the blood is spread out over a larger area, causing it to flow more slowly. In contrast, the blood flow is faster in the arteries and veins because they have smaller cross-sectional areas. The statement that the velocity of blood flow is slower in the veins than in the capillaries due to the veins having a larger diameter is incorrect. Similarly, the statement that the velocity of blood flow is slower in the arteries than in the capillaries due to the arteries having a relatively large diameter is also incorrect.Rate this question:
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- 47.
The absolute refractory period in cardiac muscle:
- A.
Is shorter than that in skeletal muscle.
- B.
Varies dramatically.
- C.
Is the same as that in skeletal muscle.
- D.
Is longer than that in skeletal muscle.
Correct Answer
D. Is longer than that in skeletal muscle.Explanation
The absolute refractory period in cardiac muscle is longer than that in skeletal muscle. During the absolute refractory period, the cardiac muscle is unable to respond to any additional stimuli, preventing the muscle from being stimulated again until the refractory period is over. This longer refractory period in cardiac muscle allows for proper coordination and prevents the muscle from entering a state of tetanus, ensuring that the heart is able to contract and relax rhythmically. In contrast, the absolute refractory period in skeletal muscle is relatively shorter, allowing for rapid and repeated contractions.Rate this question:
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- 48.
Interferons:
- A.
Are routinely used in nasal sprays for common cold.
- B.
Interfere with viral replication within cells.
- C.
Are virus-specific so that an interferon produced against one virus could not protect cells against another virus.
- D.
Act by increasing the rate of cell division.
Correct Answer
B. 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.Rate this question:
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- 49.
When the femoral artery passes behind the knee it becomes the?
- A.
Posterior tibial artery.
- B.
Fibular artery.
- C.
Deep femoral artery.
- D.
Popliteal artery.
Correct Answer
A. Posterior tibial artery.Explanation
When the femoral artery passes behind the knee, it continues as the popliteal artery. The popliteal artery then branches into two arteries: the posterior tibial artery and the fibular artery. The posterior tibial artery supplies blood to the calf and foot, while the fibular artery supplies blood to the lateral compartment of the leg. Therefore, the correct answer is the posterior tibial artery.Rate this question:
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- 50.
Which of the following is associated with passive immunity?
- A.
Infusion of weakened viruses.
- B.
Passage of IgG antibodies from a pregnant mother to her fetus.
- C.
Long-term immune protection.
- D.
Booster shot.
Correct Answer
B. 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.Rate this question:
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Current Version
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Dec 12, 2024Quiz Edited by
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May 25, 2009Quiz Created by
Chamula
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