Chapter 19 - Cardiovascular System: The Blood

Red blood cells contain hemoglobin and function in gas transport.

Erythropoietin is a hormone that stimulates the production of red blood cells in the bone marrow. It acts on pluripotent cells, which are capable of differentiating into various blood cell types, including red blood cell precursors. Erythropoietin promotes the proliferation and maturation of these precursor cells, increasing their numbers and ultimately leading to the production of more red blood cells. This hormone is released by the kidneys in response to low oxygen levels in the body, and it plays a crucial role in maintaining adequate oxygen delivery to tissues.

The correct answer is 2 because lymphocytes are a type of white blood cell that includes B cells, T cells, and natural killer cells. These cells are important for the immune response and play a key role in fighting off infections and diseases.

Platelets are cell fragments enclosed by a piece of the cell membrane of megakaryocytes. They are involved in blood clotting and contain clotting factors.

Thrombopoietin is the hormone that stimulates the formation of platelets.

The given description of a white blood cell with a kidney-shaped nucleus and the ability to perform phagocytosis matches the characteristics of monocytes. Monocytes are a type of white blood cell that have a large, kidney-shaped nucleus and are capable of engulfing and destroying foreign particles through phagocytosis. Therefore, the correct answer is 3.

Wandering macrophages are a type of monocyte that roams the tissues and gathers at sites of infection or inflammation. Monocytes are a type of white blood cell that can differentiate into macrophages, which are responsible for engulfing and destroying pathogens. Therefore, option 16, wandering macrophages, is the correct answer.

Lymphoid cells give rise to lymphocytes.

Neutrophils are indeed the most numerous white blood cells in a differential white blood cell count of a healthy individual. They play a crucial role in the immune response by engulfing and destroying bacteria and other foreign substances. This high number of neutrophils is a normal finding in a healthy individual and helps to maintain the body's defense against infections.

Myeloid stem cells give rise to various types of blood cells, including red blood cells, monocytes, neutrophils, eosinophils, basophils, and platelets.

Reticulocytes are immature red blood cells that are released from the red bone marrow. As they continue to mature, they lose their reticulum and become fully functional red blood cells. Therefore, reticulocytes are the correct answer to the given question.

Fixed macrophages are a type of immune cell that reside in a particular tissue and do not circulate in the bloodstream. They are found in various organs and tissues, including the lungs where they are called alveolar macrophages. These macrophages play a crucial role in immune defense by engulfing and destroying pathogens and cellular debris. Therefore, the given answer, 15, which corresponds to fixed macrophages, is correct.

Eosinophils are a type of white blood cell that combat the effects of histamine and other mediators of inflammation in allergic reactions. They are also involved in phagocytizing antigen-antibody complexes.

Basophils are involved in inflammatory and allergic reactions and play a role in hypersensitivity reactions. They release histamine and other chemicals that promote inflammation and attract other immune cells to the site of inflammation. Basophils are a type of white blood cell and are part of the innate immune system. They are typically found in low numbers in the bloodstream but can increase in response to certain triggers, such as allergies or parasitic infections.

Neutrophils are the correct answer because they are a type of white blood cell that responds to tissue destruction by bacteria. They release lysozyme, strong oxidants, and defensins, which help to kill and destroy the bacteria. Neutrophils are part of the innate immune system and are one of the first responders to infection or tissue damage. They are highly effective at phagocytosis and are able to engulf and destroy bacteria.

Hemoglobin is a protein found in red blood cells that plays a crucial role in transporting oxygen from the lungs to the body tissues and carrying carbon dioxide from the tissues back to the lungs. Additionally, hemoglobin also helps in maintaining blood pressure by regulating the release of nitric oxide, a molecule that relaxes and dilates blood vessels. Therefore, it is correct to say that hemoglobin functions in transporting both oxygen and carbon dioxide and in regulating blood pressure.

Pluripotent cells are the cells that give rise to all the formed elements in blood, including neutrophils, lymphocytes, monocytes, eosinophils, basophils, red blood cells, reticulocytes, polymorphs, platelets, fixed macrophages, and wandering macrophages. These pluripotent cells are capable of differentiating into various types of blood cells and are the source of all the different cell types found in the blood.

Neutrophils are a type of white blood cell that play a key role in the immune response to infections. They are characterized by their multi-lobed nucleus, with older neutrophils having several differently shaped nuclear lobes. The given answer, 10, corresponds to "polymorphs", which is another term for neutrophils. Therefore, the correct answer is 10.

Plasma minus its clotting proteins is called serum. When blood is allowed to clot, it separates into two components: the solid clot and the liquid serum. Serum does not contain clotting factors, as they are removed during the clotting process. Therefore, serum is the correct term for plasma without its clotting proteins.

Red blood cells (RBCs) are highly specialized for oxygen transport because they contain hemoglobin, which is responsible for binding and carrying oxygen. Additionally, RBCs lack a nucleus, allowing for more space to accommodate hemoglobin and increasing their oxygen-carrying capacity. The biconcave shape of RBCs provides a large surface area for the efficient exchange of oxygen and carbon dioxide. Lastly, RBCs can carry up to four oxygen molecules for each hemoglobin molecule, maximizing their oxygen-carrying capacity.

A person with type A Rh- blood can receive a blood transfusion from individuals who have the same blood type or individuals who have O Rh- blood type. This is because individuals with type A Rh- blood have antibodies against the Rh antigen, which is present in types A Rh+ and B Rh- blood. However, they can receive blood from individuals with O Rh- blood type because O blood type does not have the Rh antigen. Therefore, the correct answer is 4 and 5.

The correct answer is 19 because cytokines are signaling molecules that play a crucial role in stimulating the formation of white blood cells. Cytokines can regulate the production, differentiation, and maturation of various immune cells, including white blood cells. Therefore, by stimulating the production of cytokines, the formation of white blood cells can be enhanced.

Clot retraction refers to the consolidation or tightening of the fibrin clot, which helps to bring the edges of a damaged vessel closer together. This process is important in the healing of wounds and the prevention of excessive bleeding. Clot retraction involves the contraction of platelets and the rearrangement of fibrin strands, resulting in the formation of a more stable clot. This allows for the subsequent stages of tissue repair to take place.

Colony-forming units are individual forms of progenitor cells that give rise to different types of blood cells. They are named based on the mature elements in the blood they will ultimately produce. Therefore, option 7, colony-forming units, is the correct answer.

When iron (Fe3+) is released during the breakdown of damaged red blood cells (RBCs), it attaches to transferrin, a protein that binds and transports iron in the blood. Transferrin then carries the iron to the bone marrow, where it is used in the synthesis of hemoglobin. Hemoglobin is an essential component of RBCs, responsible for carrying oxygen throughout the body. Therefore, the iron released from damaged RBCs is recycled and utilized in the production of new RBCs in the bone marrow.

The correct answer is 1, 2, 3, 4. White blood cells (WBCs) leave the blood stream by emigration, which is facilitated by adhesion molecules that help them stick to the endothelium. Neutrophils and macrophages are both active in phagocytosis, the process of engulfing and destroying pathogens. The attraction of phagocytes to microbes and inflamed tissue is called chemotaxis.

Progenitor cells are cells that are more specialized than pluripotent cells but less specialized than fully differentiated cells. They are capable of giving rise to more specific formed elements of blood, such as red blood cells, white blood cells, and platelets. Therefore, the correct answer is 13.

Clot formation requires vitamin K, calcium, and fibrinogen. Vitamin K is necessary for the production of certain clotting factors, calcium is required for the activation of these clotting factors, and fibrinogen is converted into fibrin, which forms the meshwork of the clot. Prostacyclin inhibits platelet aggregation and plasmin is responsible for breaking down the clot. Therefore, prostacyclin (3) and plasmin (4) are not required for clot formation.

When a person with B positive blood receives a transfusion of type AB positive blood, the recipient's antibodies, which are naturally present in their blood, will react with the donor's red blood cells (RBCs). This is because the recipient's antibodies recognize the antigens on the donor's RBCs as foreign and initiate an immune response. This reaction can lead to a transfusion reaction, causing symptoms such as fever, chills, and potentially more severe complications.

The correct order of the steps involved in hemostasis is as follows: First, there is a reduction of blood loss by the initiation of a vascular spasm (step 5). Then, platelets adhere to and aggregate on the damaged vessel (step 3). Next, the prothrombinase is formed by either the extrinsic or intrinsic pathway (step 4). After that, prothrombin is converted into thrombin (step 2). Finally, fibrinogen is converted into fibrin (step 1). This sequence of events allows for the formation of a blood clot to stop bleeding.

Polycythemia is a condition characterized by an excessive increase in the number of red blood cells in the body. In this condition, the blood becomes thicker and more viscous. Since erythropoietin is a hormone produced by the kidneys to stimulate the production of red blood cells, it is logical to assume that polycythemia would cause a decrease in erythropoietin levels, as the body already has an excess of red blood cells. Therefore, polycythemia would not cause an increase in erythropoietin.