Professor Tate's Test 2: Ch 18-21

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.

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.

The AV valves, including the mitral valve and tricuspid valve, are supported by chordae tendinae, which are string-like structures that prevent the valves from blowing back up into the atria when the ventricles contract. This ensures that blood flows in the correct direction, from the atria to the ventricles, and prevents any backflow into the atria.

The normal heart sounds, commonly known as "lub-dub," are caused by the closure of the heart valves. The first sound (lub) is produced when the atrioventricular (AV) valves close at the beginning of ventricular systole, preventing the backflow of blood into the atria. The second sound (dub) occurs when the semilunar valves close at the end of ventricular systole, preventing the backflow of blood into the ventricles. These valve closures create the characteristic heart sounds that can be heard with a stethoscope during a physical examination.

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.

The statement "A specific immune mechanism is often involved in directing complement to its target" is correct. Complement is a part of the immune system and plays a crucial role in the defense against pathogens. It can be activated through three pathways: classical, lectin, and alternative. Once activated, complement proteins are directed towards their target, which can be pathogens or damaged cells, through a specific immune mechanism. This mechanism ensures that complement is targeted specifically to the site of infection or injury, enhancing the immune response and promoting the elimination of the threat.

In clonal selection of B cells, antigens are responsible for determining which cells will eventually become cloned. Antigens are foreign substances that trigger an immune response in the body. When B cells encounter antigens, they bind to them using their antibody receptors. This binding activates the B cells, leading to their proliferation and differentiation into antibody-producing plasma cells. Therefore, antigens play a crucial role in the clonal selection process by selecting and activating specific B cells that can effectively target and eliminate the invading antigens.

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.

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.

Amylase is not an important inflammatory mediator because it is an enzyme that is involved in the digestion of carbohydrates, particularly starch. It is not directly involved in the inflammatory response, which is characterized by the release of various chemical mediators such as prostaglandins, kinins, complement, and histamine. These mediators play important roles in the initiation and regulation of inflammation.

Hassall's corpuscles, also known as thymic corpuscles, are structures found in the thymus gland. They are composed of concentric layers of epithelial cells. The main function of Hassall's corpuscles is not to destroy T cells, but rather to assist in the production of lymphocytes. These corpuscles are involved in the maturation process of T cells and play a role in the development of the immune system. They are not responsible for the destruction of T cells, as stated in the given answer.

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.

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.

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.

The foramen ovale is a small opening in the septum between the two atria of the fetal heart. It allows blood to bypass the non-functioning fetal lungs and flow from the right atrium to the left atrium. This is important because the lungs are not yet fully developed and do not participate in gas exchange. The foramen ovale closes shortly after birth, allowing the heart to function as a separate pulmonary and systemic circulation.

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.

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.

A ring of lymphoid tissue that appears as a swelling of the mucosa in the oral cavity is called a tonsil. Tonsils are part of the body's immune system and help to fight off infections. They act as a defense mechanism by trapping and filtering out harmful bacteria and viruses that enter the body through the mouth and throat. Tonsils can become inflamed and swollen during an infection, causing symptoms such as sore throat and difficulty swallowing. In severe cases, tonsils may need to be surgically removed.

The pericardial cavity contains a lubricating fluid called serous fluid. This fluid helps reduce friction between the fibrous pericardium and the serous pericardium, allowing the heart to move and beat smoothly within the pericardial cavity. The serous fluid also helps to cushion and protect the heart from external forces.

The redness and heat of an inflamed area are due to local hyperemia, which means increased blood flow to the area. This increased blood flow is caused by vasodilation, which is the widening of blood vessels. When blood vessels widen, more blood can flow through them, resulting in redness and heat. Therefore, vasodilation is the correct answer as it explains the cause of the redness and heat in an inflamed area.

Peyer's patches are clumps of lymph follicles found in the distal portion of the small intestine. They play a crucial role in the immune system by monitoring and defending against pathogens that enter the digestive tract. Islets of Langerhans are found in the pancreas and are responsible for producing insulin. Villi are finger-like projections in the small intestine that increase the surface area for nutrient absorption. Rugae are folds in the stomach that allow for expansion.

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.

Heart block refers to a condition where there is a disruption in the electrical signals that regulate the heartbeat. The AV node, or atrioventricular node, is an important part of the heart's electrical conduction system. It is responsible for transmitting the electrical signals from the atria to the ventricles. Damage to the AV node can result in heart block, as it can interfere with the proper transmission of these signals and disrupt the coordination of the heart's contractions. Therefore, the correct answer is AV node.

The correct answer is coronary arteries. The myocardium, which is the muscular tissue of the heart, receives oxygenated blood through the coronary arteries. These arteries branch off from the aorta and supply the heart with the necessary oxygen and nutrients for its proper functioning. The coronary arteries ensure that the myocardium has a sufficient blood supply to meet its high metabolic demands.

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.

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.

Chemotaxis is the process by which neutrophils and other white blood cells are attracted to an inflammatory site. During inflammation, damaged cells release chemical signals called chemotactic factors, which act as attractants for white blood cells. These cells then migrate towards the site of inflammation, guided by the concentration gradient of these chemotactic factors. Once at the site, the white blood cells can help to eliminate pathogens and promote tissue healing. Margination refers to the adherence of white blood cells to the walls of blood vessels, phagocytosis is the process of engulfing and digesting pathogens, and diapedesis is the process of white blood cells squeezing out of blood vessels and into tissues.

If the cardiac muscle is deprived of its normal blood supply, the damage would primarily result from a decreased delivery of oxygen. The cardiac muscle requires a constant supply of oxygen to function properly, and without it, the muscle cells cannot produce enough energy to sustain their normal activities. This lack of oxygen can lead to cell death and damage to the cardiac muscle, potentially causing heart failure or other cardiovascular complications.

In the lungs, low oxygen levels cause vasoconstriction, which means the blood vessels constrict or narrow. This response helps redirect blood flow to areas with higher oxygen levels. On the other hand, high oxygen levels in the lungs cause vasodilation, which means the blood vessels relax and widen. This allows for increased blood flow and oxygen delivery to the surrounding tissues.

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.

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.

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.

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.

When the lymphatics are blocked due to tumors, the flow of lymph fluid is obstructed. This leads to an accumulation of fluid in the affected area, causing severe localized edema distal to the blockage. The increased pressure in the lymphatics proximal to the blockage does not result in abnormally high lymph drainage from the distal region. Additionally, shrinkage of tissues distal to the blockage is not caused by inadequate delivery of lymph, but rather by the lack of nutrients and oxygen due to the blockage.

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.

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.

A second exposure to an allergen is not a mechanism for the development of autoimmune disorders. Autoimmune disorders occur when the immune system mistakenly attacks the body's own cells and tissues. The other options provided explain mechanisms that can lead to autoimmune disorders. Exposure of previously "hidden" self-antigens to the adaptive immune system can trigger an autoimmune response. Cross-reaction of antibodies formed against foreign antigens with self-antigens can also lead to autoimmune disorders. Mutation followed by the appearance of membrane proteins not previously recognized by the immune system can cause an autoimmune response as well.

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.

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.

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.

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.

Plasma cells are responsible for releasing antibodies that act against specific foreign substances. Lymph nodes are responsible for filtering lymph and housing immune cells, but they do not directly release antibodies. T lymphocytes are a type of immune cell that plays a role in cell-mediated immunity, but they do not release antibodies. Medullary cords are structures found within lymph nodes that contain immune cells, but they do not release antibodies either. Therefore, the correct answer is plasma cells, as they are the primary source of antibodies against foreign substances.

The statement "The ability of one's state of mind to influence immune function is now accepted as proven by the medical community" is the correct answer because it accurately reflects the current understanding in the medical community. Numerous studies have shown that psychological factors such as stress, emotions, and mental state can have a significant impact on the immune system. This field of research, known as psychoneuroimmunology, explores the complex interactions between the nervous system, endocrine system, and immune system.

During ventricular systole, the ventricles of the heart contract, forcing blood out of the heart. The aorta and pulmonary arteries are the vessels that receive this blood. The aorta carries oxygenated blood from the left ventricle to the rest of the body, while the pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs for oxygenation. Therefore, blood enters both the aorta and pulmonary arteries during ventricular systole.

Complement fixation is the main mechanism by which antibodies provide protection. Complement fixation refers to the activation of the complement system, a group of proteins that work together to destroy pathogens. When antibodies bind to antigens on the surface of pathogens, they activate the complement system, leading to the formation of a membrane attack complex that can destroy the pathogen. This mechanism is crucial for the immune response and plays a key role in eliminating invading cells and providing protection against infections.

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.

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.

Our genes determine what specific foreign substances our adaptive immune system will be able to recognize and resist. This is because our genes encode for the production of proteins called major histocompatibility complex (MHC) molecules, which play a crucial role in presenting antigens to immune cells. MHC molecules bind to antigens and present them on the surface of cells, triggering an immune response. The specific MHC molecules produced by our genes determine which antigens can be recognized by our immune system, allowing it to mount a targeted response against foreign substances.

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.

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.

The correct answer is "Cross-linked cell-bound antigens on red blood cells when blood types are properly matched." This is because antibodies do not cross-link cell-bound antigens on red blood cells when blood types are properly matched. Instead, they bind to and neutralize chemical toxins released by bacteria or other microorganisms, link soluble antigens together so that they fall out of solution, and target foreign cells so that complement proteins can cause cellular lysis.

The tricuspid valve is located between the right atrium and right ventricle of the heart. It is responsible for preventing the backflow of blood from the ventricle to the atrium during the pumping action of the heart. Systole refers to the phase of the cardiac cycle when the ventricles are contracting and pumping blood out of the heart. Therefore, when the ventricle is in systole, the tricuspid valve is closed to ensure that blood flows in the correct direction and does not flow back into the atrium.

Both lymph and venous blood flow are heavily dependent on skeletal muscle contractions and differences in thoracic pressures due to respiratory movement. Skeletal muscle contractions help to squeeze the lymphatic vessels and veins, aiding in the movement of lymph and blood back towards the heart. Additionally, during inhalation, the thoracic cavity expands and the pressure within it decreases, creating a pressure gradient that helps to pull lymph and blood towards the heart. This process is known as the respiratory pump and is essential for maintaining proper lymph and venous blood flow.

The greater saphenous vein is often used in cardiac bypass operations. This vein is the longest vein in the body and is located in the leg. It is commonly used because of its accessibility and size, which allows for the successful bypass of blocked or narrowed coronary arteries.

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.

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.

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.

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.

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The question asks for a vessel that is not a midline vessel coming off the abdominal aorta. The celiac trunk, superior mesenteric artery, and inferior mesenteric artery are all midline vessels that branch off the abdominal aorta. The median sacral artery is also a midline vessel that runs along the sacrum. Therefore, the only option that is not a midline vessel is the splenic artery.

B cells respond to the initial antigen challenge by immediately producing antigen-specific antibodies. This is an important part of the humoral immune response, as it allows for the rapid neutralization and elimination of the invading pathogen. Additionally, B cells also produce progeny cells that include plasma cells and memory cells. Plasma cells are responsible for the ongoing production and secretion of antibodies, while memory cells provide long-term immunity by remembering the specific antigen and mounting a faster and stronger response upon re-exposure. Together, these responses contribute to the effective elimination of the antigen and the establishment of immunological memory.

The first major branch of the aortic arch is the brachiocephalic branch. This branch is responsible for supplying blood to the right arm, right side of the head, and neck. It further divides into the right common carotid artery and the right subclavian artery, which continue to distribute blood to different parts of the body. The brachiocephalic branch plays a crucial role in ensuring proper blood flow and oxygenation to these areas.

Veins are the type of blood vessels that contain valves. The function of these valves is to prevent the backward flow of blood. When the heart pumps blood, the valves in the veins open to allow blood to flow towards the heart. However, when the muscles surrounding the veins relax, the valves close, preventing the blood from flowing backward. This ensures that the blood flows in one direction, towards the heart, and helps maintain efficient circulation throughout the body.

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