60 Questions
What is the primary cause of hemolytic disease of the newborn (erythroblastosis fetalis) described in the passage?
Rh-negative mothers carrying Rh-positive fetuses
What is the most serious complication of severe hemolysis in the fetus described in the passage?
Infant death in utero
What is the neurological syndrome that can develop in infants with erythroblastosis fetalis, especially if complicated by hypoxia?
Kernicterus
Why is the concentration of unconjugated bilirubin very high in infants with erythroblastosis fetalis?
Increased production and immaturity of the bilirubin-conjugating system
How does sensitization of Rh-negative mothers by carrying an Rh-positive fetus typically occur?
At birth of the first Rh-positive child
What percentage of Rh-positive fetuses born to Rh-negative mothers who have been pregnant one or more times with Rh-positive fetuses develop hemolytic disease?
17%
Which of the following cell types arise from a common precursor?
Neutrophils and monocytes
What is the approximate normal range of total white blood cells per microliter in human blood?
4000 - 11,000
Which of the following cell types are derived from bone marrow stem cells?
All of the above
What is the percentage range for neutrophils among the total white blood cells?
50-70%
Which of the following statements about hematopoietic stem cells (HSCs) is true?
They can completely replace the bone marrow when injected into a patient whose own bone marrow has been destroyed.
What is the approximate normal range for erythrocytes (red blood cells) per microliter in human blood?
4.8 - 5.4 million
What is the primary function of the capillary beds in the cardiovascular system?
To transfer oxygen and nutrients from the blood to tissues and collect metabolic wastes
What is the primary mechanism by which fluid leaves the circulation across the walls of capillaries?
Filtration
Which of the following is NOT a factor that governs the flow of blood through each segment of the circulation?
Metabolic rate
What is the most common cause of hypertension in humans?
Unknown
What is the main consequence of untreated hypertension?
Serious health consequences
Which of the following is NOT a characteristic of the contractile properties and regulatory mechanisms of the vasculature?
They are independent of physical principles
What is the primary reason for the popularity of banking one's own blood before elective surgery?
Fear of transmission of infectious diseases from heterologous transfusions
What is the advantage of autologous transfusion mentioned in the text?
It eliminates the risk of transfusion reactions
Which of the following statements about the Rh group is true?
The D antigen is the most antigenic component of the Rh group
What is the purpose of checking the action of the donor's plasma on the recipient cells before a transfusion?
To determine the risk of transfusion reactions
What is the purpose of withdrawing the patient's own blood before elective surgery?
To use for autologous transfusion if needed during surgery
What is the function of the D protein in the Rh group?
Its function is unknown
What is the primary function of hemoglobin in red blood cells?
To transport oxygen to peripheral tissues
Which of the following statements about fetal hemoglobin is true?
It is specialized to facilitate diffusion of oxygen from mother to fetus during development
What is the basis of the ABO blood group system?
Complex oligosaccharide structures specific to groups of individuals
What can happen when an individual receives an inappropriate blood transfusion?
The recipient's red blood cells may undergo hemolysis
What is the sequence of blood flow in the cardiovascular system?
Heart -> Arteries -> Arterioles -> Capillaries -> Venules -> Veins -> Heart
Which of the following statements about blood cells is true?
Platelets and red blood cells arise in the bone marrow and are subject to regular renewal
What is the primary function of the granules found in eosinophils?
To neutralize acidic substances
What is the primary role of lymphocytes in the body's immune defenses?
Antigen recognition and targeted immune responses
What is the primary mechanism by which platelets are produced in the body?
Budding off from the cytoplasm of megakaryocytes
What is the primary function of hemoglobin in red blood cells?
To transport oxygen and carbon dioxide
What is the primary mechanism by which fluid leaves the circulation and enters the tissues across the walls of capillaries?
Hydrostatic pressure gradients
What is the primary purpose of checking the action of the donor's plasma on the recipient cells before a blood transfusion?
To assess the presence of antibodies that could cause an adverse reaction
What is the term for bone marrow that is infiltrated with fat and no longer actively producing blood cells?
Yellow marrow
Which cell type forms the majority (75%) of the cells in the bone marrow, responsible for producing white blood cells?
Myeloid series cells
What is the term for bone marrow cells capable of producing all types of blood cells?
Hematopoietic stem cells (HSCs)
What reflects the difference between white blood cell and red blood cell production in the bone marrow?
Average life span of cells
What happens in diseases where bone marrow becomes destroyed or fibrosed in adults?
Extramedullary hematopoiesis
What is the term for active cellular marrow in the bone?
Red marrow
What is the specific gravity of blood?
1.055
Why does blood appear scarlet red when taken from arteries and purplish from veins?
Due to the difference in O2 content
What is the primary mechanism that leads to the formation of a definitive clot after a blood vessel is damaged?
Activation of the coagulation cascade and conversion of fibrinogen to insoluble fibrin
How does blood act as a transport medium in the body?
By carrying substances to different parts of the body
What is the approximate percentage of plasma in the total circulating blood volume?
55%
What is the primary cause of the vasoconstriction that occurs in an injured arteriole or small artery?
Serotonin and other vasoconstrictors released from adhering platelets
What is the fundamental reaction involved in the clotting mechanism described in the passage?
Conversion of fibrinogen to insoluble fibrin
Where are red blood cells, white blood cells, and platelets formed in adults?
Bone marrow
What is the primary function of the temporary hemostatic plug formed by platelets after a blood vessel is damaged?
To constrict the damaged vessel and prevent further blood loss
What is the role of blood cells in maintaining the cellular environment?
Specialize to perform various functions within the body
What is the primary purpose of the series of enzymatic reactions and clotting factors involved in the clotting mechanism described in the passage?
To convert the temporary platelet plug into a definitive clot
What is the primary role of fibrin in the clotting mechanism described in the passage?
To bind together the platelets in the temporary plug and convert it into a definitive clot
What is the primary cause of dangerous hemolytic transfusion reactions during blood transfusions?
Mismatched plasma with red cells from the recipient
Why does the dilution of plasma in the recipient usually prevent agglutination during blood transfusions?
Recipient's agglutinins have low titers
Which blood type is most likely to have a high frequency of plasma containing anti-B agglutinins?
Blood type O
What happens when an individual with type A blood has their plasma mixed with type B red cells?
Red cells clump due to anti-B agglutinins
Why is hemolysis more likely to occur when recipient's plasma has agglutinins against the donor's red cells?
Recipient's antibodies cause donor red cell lysis
What is the primary method used for ABO blood typing?
Mixing red blood cells with antisera containing agglutinins
Study Notes
Hemolytic Disease of the Newborn
- When anti-Rh agglutinins cross the placenta to an Rh-positive fetus, they can cause hemolysis and various forms of hemolytic disease of the newborn (erythroblastosis fetalis).
- Hemolysis in the fetus can cause anemia, severe jaundice, and edema (hydrops fetalis).
- Kernicterus, a neurologic syndrome, may also develop, especially if birth is complicated by a period of hypoxia.
Blood Cells and Bone Marrow
- There are separate pools of progenitor cells for megakaryocytes, lymphocytes, erythrocytes, eosinophils, and basophils; neutrophils and monocytes arise from a common precursor.
- The bone marrow stem cells are also the source of osteoclasts, Kupffer cells, mast cells, dendritic cells, and Langerhans cells.
- HSCs are few in number but are capable of completely replacing the bone marrow when injected into a patient whose own bone marrow has been entirely destroyed.
White Blood Cells
- Normally, human blood contains 4,000-11,000 white blood cells per microliter.
- Neutrophils are the most numerous, making up 50-70% of total white blood cells.
- Lymphocytes make up 20-40%, monocytes make up 2-8%, and eosinophils and basophils make up 1-4%.
Erythrocytes
- Erythrocytes (red blood cells) contain hemoglobin, which transports oxygen to peripheral tissues.
- Fetal hemoglobin is specialized to facilitate diffusion of oxygen from mother to fetus during development.
- Mutated forms of hemoglobin lead to red cell abnormalities and anemia.
Blood Groups and Transfusion Reactions
- The ABO blood group system is based on complex oligosaccharide structures specific to groups of individuals.
- Incompatible blood transfusions can trigger the production of antibodies, leading to erythrocyte agglutination and potentially serious consequences.
- Transfusion reactions occur when blood is transfused into an individual with an incompatible blood type, resulting in hemolysis and the liberation of free hemoglobin into the plasma.
Cardiovascular System and Blood Flow
- Blood flows from the heart to arteries and arterioles, then to capillaries, and eventually to venules and veins and back to the heart.
- The cardiovascular system has specific contractile properties and regulatory mechanisms that subserve physiologic function.
- Transfer of oxygen and nutrients from the blood to tissues, as well as collection of metabolic wastes, occurs exclusively in the capillary beds.
Platelets and Blood Clotting
- Platelets are small, granulated bodies that aggregate at sites of vascular injury.
- Megakaryocytes in the bone marrow form platelets by pinching off bits of cytoplasm and extruding them into the circulation.
- The clotting mechanism involves a cascade of enzymatic reactions and a series of numbered clotting factors, resulting in the conversion of fibrinogen to fibrin.
Test your knowledge on the different pools of progenitor cells for various types of blood cells, including megakaryocytes, lymphocytes, erythrocytes, eosinophils, basophils, neutrophils, and monocytes. Learn about the source of various immune and bone cells from bone marrow stem cells.
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