1.
Which of the following is the innermost layer of a blood vessel?
Correct Answer
A. Tunica intima
Explanation
The innermost layer of a blood vessel is called the tunica intima. It is composed of a thin layer of endothelial cells that line the lumen of the blood vessel. The tunica intima helps regulate blood flow and prevents clotting by releasing substances that promote vasodilation or vasoconstriction. It also acts as a barrier between the blood and the surrounding tissues.
2.
Which of these proteins functions to store or transport oxygen?
Correct Answer
A. Hemoglobin
Explanation
Hemoglobin is the correct answer because it is a protein found in red blood cells that is responsible for carrying oxygen from the lungs to the tissues of the body. It binds to oxygen in the lungs and releases it in the tissues, allowing for oxygen transport throughout the body. Ferritin, hemosiderin, and transferrin are also proteins, but they do not directly function in the storage or transport of oxygen. Ferritin stores iron, hemosiderin is a breakdown product of ferritin, and transferrin transports iron in the blood. Therefore, the correct answer is hemoglobin.
3.
RBCs move single file through this structure.
Correct Answer
C. Capillary
Explanation
Capillaries are the smallest blood vessels in the body and have a narrow diameter, allowing red blood cells (RBCs) to only pass through them in a single file. This is due to the size of the capillary lumen, which is smaller than the diameter of an RBC. As RBCs travel through the capillaries, they exchange oxygen and nutrients with surrounding tissues and remove waste products. The single file movement of RBCs through capillaries ensures efficient and controlled exchange of substances between the blood and tissues.
4.
The process of fibrinolysis
Correct Answer
C. Dissolves clots.
Explanation
The process of fibrinolysis refers to the breakdown of fibrin, which is a protein involved in blood clot formation. This process is responsible for dissolving clots that have formed in the blood vessels. Fibrinolysis occurs when plasmin, an enzyme, breaks down the fibrin meshwork of a clot, resulting in the dissolution of the clot. Therefore, the correct answer is "dissolves clots."
5.
The combination of plasma and formed elements is called
Correct Answer
C. Whole blood.
Explanation
The combination of plasma and formed elements refers to the complete composition of blood, which includes red blood cells, white blood cells, and platelets suspended in plasma. This combination is known as whole blood. Serum is the liquid portion of blood that remains after the removal of clotting factors, while lymph is a clear fluid that circulates in the lymphatic system. Extracellular fluid refers to the fluid outside the cells, and packed blood is not a recognized term in relation to blood composition.
6.
Some rat poisons contain a toxin that blocks the liver's ability to utilize vitamin K. Animals that consume this poison would die of
Correct Answer
C. Hemorrhage.
Explanation
Rat poisons that block the liver's utilization of vitamin K prevent the production of clotting factors, leading to a deficiency in blood clotting. As a result, animals that consume this poison would experience excessive bleeding, both internally and externally, which can ultimately lead to hemorrhage and death. Anemia refers to a deficiency in red blood cells, acidosis is a condition characterized by excessive acidity in the blood, and thrombocytopenia is a low platelet count, none of which directly relate to the effects of the poison.
7.
In large arteries, the thick layer of elastic fibers is called the
Correct Answer
D. Internal elastic membrane.
Explanation
The correct answer is "internal elastic membrane." In large arteries, the internal elastic membrane is a thick layer of elastic fibers that separates the tunica intima from the tunica media. It provides elasticity and allows the artery to stretch and recoil with each heartbeat, helping to maintain blood pressure and flow. The tunica intima is the innermost layer of the artery, the tunica media is the middle layer, and the tunica externa is the outermost layer. The external elastic membrane is found between the tunica media and the tunica externa.
8.
Which of these is not one of the formed elements of blood?
Correct Answer
C. Antibodies
Explanation
Antibodies are not one of the formed elements of blood. The formed elements of blood include red blood cells (RBCs), platelets, lymphocytes, and basophils. Antibodies, also known as immunoglobulins, are proteins produced by white blood cells called B lymphocytes. They play a crucial role in the immune response by recognizing and neutralizing foreign substances in the body. However, antibodies are not considered formed elements of blood because they are not cellular components but rather soluble proteins found in the plasma.
9.
________ involves a cascade of reactions leading to the conversion of fibrinogen to fibrin.
Correct Answer
D. Coagulation
Explanation
Coagulation is the correct answer because it involves a cascade of reactions that result in the conversion of fibrinogen, a soluble protein, into fibrin, an insoluble protein. This process is essential for the formation of blood clots, which help to stop bleeding and promote wound healing. Coagulation involves the activation of various clotting factors and enzymes, ultimately leading to the formation of a stable fibrin clot.
10.
________ are large phagocytic white cells that spend most of their time outside the blood as fixed and free phagocytic cells.
Correct Answer
E. Monocytes
Explanation
Monocytes are large phagocytic white cells that spend most of their time outside the blood as fixed and free phagocytic cells. They are part of the immune system and play a crucial role in engulfing and destroying foreign substances, such as bacteria and dead cells. Monocytes can migrate to tissues and differentiate into macrophages, which are highly effective in clearing infections and debris. This ability to move freely between the bloodstream and tissues makes monocytes an essential component of the body's defense against pathogens.
11.
In adults, erythropoiesis exclusively takes place in
Correct Answer
C. Red bone marrow.
Explanation
Erythropoiesis is the process of producing red blood cells. In adults, this process primarily occurs in the red bone marrow, which is found within certain bones such as the sternum, ribs, and pelvis. The red bone marrow contains stem cells that differentiate into red blood cells. The liver is involved in the production of red blood cells during fetal development, but its role diminishes after birth. Yellow bone marrow is mainly composed of fat cells and does not play a significant role in erythropoiesis. The spleen and lymphoid tissue are primarily involved in immune function and do not participate in erythropoiesis.
12.
A hematocrit provides information on
Correct Answer
C. Formed elements abundance.
Explanation
A hematocrit measures the proportion of red blood cells to the total volume of blood. This information is used to determine the abundance of formed elements, specifically red blood cells, in the blood. The hematocrit does not provide information on blood type, clotting factors, plasma composition, or sedimentation rate.
13.
Platelets are
Correct Answer
E. Cytoplasmic fragments of large cells.
Explanation
Platelets are cytoplasmic fragments of large cells. This means that platelets are not complete cells themselves, but rather small fragments that are derived from larger cells in the bone marrow called megakaryocytes. These fragments are released into the bloodstream and play a crucial role in blood clotting. They help to form a plug at the site of injury, preventing excessive bleeding. Platelets do not have a nucleus, which is a characteristic of complete cells.
14.
The most abundant component of plasma is
Correct Answer
C. Water.
Explanation
Water is the most abundant component of plasma because it makes up approximately 90% of plasma volume. Plasma is the liquid portion of blood and serves as a carrier for various substances such as nutrients, hormones, and waste products. It also helps maintain blood pressure and regulates body temperature. While ions, proteins, gases, and nutrients are present in plasma, they are not as abundant as water.
15.
Eileen is a strict vegan and therefore eats no animal products. She develops an anemia that her doctor thinks is caused by a nutritional deficiency. Which of the following is the likeliest candidate?
Correct Answer
B. Vitamin B12 deficiency
Explanation
Eileen's strict vegan diet, which excludes all animal products, puts her at a higher risk for developing a vitamin B12 deficiency. Vitamin B12 is primarily found in animal products such as meat, fish, eggs, and dairy. Since Eileen does not consume these foods, she may not be getting enough vitamin B12, leading to anemia. Vitamin B12 is essential for the production of healthy red blood cells, and a deficiency can result in anemia. Therefore, the likeliest candidate for Eileen's anemia is a vitamin B12 deficiency.
16.
The intrinsic pathway of coagulation is activated by the
Correct Answer
C. Release of tissue factor (Factor III) by damaged endothelium.
Explanation
The correct answer is the release of tissue factor (Factor III) by damaged endothelium. The intrinsic pathway of coagulation is activated by the release of tissue factor, which is a protein that initiates the clotting process. When the endothelium, the inner lining of blood vessels, is damaged, it releases tissue factor, triggering a series of reactions that lead to the formation of a blood clot. This pathway is important for the body's response to injury and helps to prevent excessive bleeding.
17.
Which of these descriptions best matches the term lymphocytes?
Correct Answer
C. Defend against specific pathogens or toxins
Explanation
Lymphocytes are a type of white blood cell that plays a crucial role in the immune system. They are responsible for defending the body against specific pathogens or toxins. Lymphocytes recognize and target foreign substances, such as bacteria or viruses, and initiate an immune response to eliminate them. This can involve producing antibodies or directly attacking and destroying the pathogens. Elevated levels of lymphocytes are often observed in individuals with allergies, as their immune system is hypersensitive and reacts strongly to harmless substances.
18.
The level of erythropoietin in the blood would rise due to all of the following, except
Correct Answer
D. During periods of fasting.
Explanation
During periods of fasting, the body's energy stores are depleted, leading to a decrease in erythropoietin production. Erythropoietin is a hormone that stimulates the production of red blood cells, which are responsible for carrying oxygen to tissues. In contrast, anemia, high altitudes, hemorrhage, and disrupted blood flow to the kidneys can all trigger the release of erythropoietin in order to increase red blood cell production and improve oxygen delivery.
19.
The inferior vena cava is classified as a(n)
Correct Answer
A. Large vein.
Explanation
The inferior vena cava is classified as a large vein because it is the largest vein in the human body. It carries deoxygenated blood from the lower body back to the heart.
20.
White blood cells that are increased in allergic individuals are the
Correct Answer
B. EosinopHils.
Explanation
Eosinophils are white blood cells that are increased in allergic individuals. These cells play a crucial role in the immune response to allergens and parasitic infections. Eosinophils are responsible for releasing substances that help to control inflammation and fight against invading pathogens. Their increased presence in allergic individuals indicates an allergic response or an ongoing parasitic infection. Neutrophils, basophils, lymphocytes, and monocytes are also types of white blood cells, but eosinophils specifically play a prominent role in allergic reactions.
21.
More than 95 percent of the protein in a red blood cell is
Correct Answer
C. Hemoglobin.
Explanation
Hemoglobin is the correct answer because it is the main protein found in red blood cells. It is responsible for carrying oxygen from the lungs to the rest of the body and plays a crucial role in the transportation of gases. Albumin is a protein found in blood plasma, not specifically in red blood cells. Porphyrin is a compound that helps in the production of heme, which is a component of hemoglobin. Immunoglobulin and fibrinogen are proteins involved in the immune response and blood clotting respectively, but they are not the main proteins found in red blood cells.
22.
The most numerous white blood cells in peripheral circulation are the
Correct Answer
A. NeutropHils.
Explanation
Neutrophils are the most numerous white blood cells in peripheral circulation. They play a critical role in the immune response by engulfing and destroying bacteria and other pathogens. Neutrophils are highly mobile and are the first cells to arrive at the site of infection or inflammation. They are characterized by their multi-lobed nucleus and granular cytoplasm. Neutrophils are essential for maintaining the body's defense against infections and are often elevated in response to bacterial infections.
23.
After donating 0.5 liter of blood, one would expect
Correct Answer
A. An increased reticulocyte count.
Explanation
After donating blood, the body needs to replenish the lost blood cells. Reticulocytes are immature red blood cells that are released from the bone marrow into the bloodstream to replace the donated blood. Therefore, it is expected that there would be an increased reticulocyte count after donating blood.
24.
The waste product bilirubin is produced from
Correct Answer
C. Heme molecules lacking iron.
Explanation
Bilirubin is a waste product that is produced from heme molecules lacking iron. Heme molecules are a component of hemoglobin, the protein in red blood cells responsible for carrying oxygen. When red blood cells break down, heme molecules are released and converted into bilirubin. This bilirubin is then processed by the liver and excreted in the bile. Therefore, the correct answer is heme molecules lacking iron.
25.
Blood flow through a capillary is controlled by the
Correct Answer
C. Precapillary spHincter.
Explanation
The precapillary sphincter is responsible for controlling blood flow through capillaries. These small ring-like muscles are located at the entrance of capillaries and can constrict or relax to regulate the amount of blood flowing into the capillary bed. When the precapillary sphincter is constricted, blood flow is restricted, and when it is relaxed, blood flow increases. This mechanism allows for the selective perfusion of tissues and helps regulate blood pressure and distribution of nutrients and oxygen throughout the body.