Blood Flashcards
1
Q
What is blood?
A
Blood is the internal transport system of the body.
2
Q
What is the composition of blood?
A
Blood is composed of blood plasma and formed elements.
3
Q
What are the formed elements of blood?
A
The formed elements of blood include erythrocytes, leukocytes, and platelets.
4
Q
What is the function of erythrocytes?
A
Erythrocytes are responsible for carrying oxygen to the body’s tissues.
5
Q
What is the function of leukocytes?
A
Leukocytes are responsible for fighting infections and diseases.
6
Q
What is the function of platelets?
A
Platelets are responsible for blood clotting.
7
Q
What happens when a blood vessel breaks?
A
When a blood vessel breaks, platelets form a clot to stop the bleeding.
8
Q
How is blood replaced in an emergency?
A
Blood is replaced in an emergency through blood transfusions.
9
Q
What can the study of blood tell us about a patient?
A
The study of blood can help clinicians determine the cause of disease in their patients.
10
Q
What are the protective functions of blood?
A
Preventing blood loss and preventing infection.
11
Q
What are the transport functions of blood?
A
Delivering oxygen and nutrients to body cells, transporting metabolic waste products from cells to elimination sites, and transporting hormones from endocrine organs to their target organs.
12
Q
What are the regulatory functions of blood?
A
Maintaining appropriate body temperature, maintaining normal pH in body tissues, and maintaining adequate fluid volume in the circulatory system.
13
Q
What is the composition of whole blood?
A
Living blood cells called formed elements suspended in a nonliving fluid matrix called plasma.
55% Plasma
45 % RBC
<1% buffy Coat (Leukocytes & Platelets)
14
Q
What is plasma?
A
The liquid component of blood that makes up 55% of whole blood and contains dissolved fibrous proteins.
15
Q
What are the formed elements in blood?
A
Erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.
16
Q
What is the function of erythrocytes?
A
Transporting oxygen.
17
Q
What is the buffy coat in blood?
A
A thin, whitish layer at the erythrocyte-plasma junction that contains leukocytes and platelets.
18
Q
Why is blood classified as a connective tissue?
A
Because it contains living blood cells suspended in a nonliving fluid matrix.
19
Q
What are the three formed elements of blood?
A
Erythrocytes, leukocytes, and platelets.
20
Q
What is the hematocrit?
A
The percentage of erythrocytes in a blood sample, which is normally about 45%.
21
Q
What is the normal hematocrit range for healthy males and females?
A
Males: 47% ± 5%, Females: 42% ± 5%.
22
Q
What is blood plasma?
A
A straw-colored, sticky fluid that makes up about 55% of whole blood and contains over 100 different dissolved solutes.
23
Q
What are the major plasma components?
A
Water, electrolytes, plasma proteins, nonprotein nitrogenous substances, nutrients, respiratory gases, and hormones.
24
Q
What is the most abundant plasma protein and what is its function?
A
Albumin, which accounts for 60% of plasma protein, acts as a carrier to shuttle certain molecules through the circulation and is the major blood protein contributing to the plasma osmotic pressure.
25
What is the normal blood volume in healthy adult males and females?
Males: 5-6 L, Females: 4-5 L.
26
What happens when the number of red blood cells increases or decreases beyond the normal range?
When the number of red blood cells increases beyond the normal range, blood becomes more viscous and flows more slowly. When the number of red blood cells drops below the lower end of the range, the blood thins and flows more rapidly.
27
What are the three types of formed elements in human blood?
Erythrocytes, leukocytes, and platelets.
28
What is the structure of erythrocytes?
They are small, disc-shaped cells with a biconcave shape.
29
What is the function of erythrocytes in the blood?
They play a crucial role in oxygen and carbon dioxide transport.
30
What is the chemical composition of hemoglobin?
Hemoglobin is a protein that contains iron and binds to oxygen in the lungs and releases it in the tissues.
31
What are some disorders caused by abnormalities of erythrocytes?
Examples include anemia, sickle cell disease, and polycythemia.
32
What is hematocrit?
Hematocrit is the percentage of blood volume occupied by erythrocytes. The normal value is around 45% for men and 40% for women.
33
What problems would reduced synthesis of plasma proteins cause in a patient with liver failure due to chronic alcoholism?
Reduced synthesis of plasma proteins can cause fluid accumulation in the tissues, leading to edema and ascites.
34
What is the shape of erythrocytes and what gives them their shape?
Erythrocytes are biconcave disc-shaped cells, and their shape is maintained by a network of proteins, especially spectrin, attached to the cytoplasmic face of RBC plasma membranes.
35
What is the function of hemoglobin in erythrocytes?
Hemoglobin binds easily and reversibly with oxygen, and most oxygen carried in blood is bound to hemoglobin. It transports respiratory gases (oxygen and carbon dioxide).
36
What is the normal range of hemoglobin in adult males and females?
The normal range of hemoglobin is 13-18 grams per 100 milliliters of blood (g/100 ml) in adult males, and 12-16 g/100 ml in adult females.
37
How many hemoglobin molecules are present in a single red blood cell and how much oxygen can they transport?
A single red blood cell contains about 250 million hemoglobin molecules, and each of these tiny cells can transport about 1 billion molecules of oxygen.
38
What are the three structural characteristics that contribute to erythrocyte gas transport functions?
The small size and shape of erythrocytes provide a huge surface area relative to volume, erythrocytes are over 97% hemoglobin, and they lack mitochondria and generate ATP by anaerobic mechanisms, making them very efficient oxygen transporters.
39
What is the process of oxygen loading and unloading in the body?
Oxygen loading occurs in the lungs and oxygen-deficient blood moves through the lungs, where oxygen diffuses from the air sacs of the lungs into the blood and then into the erythrocytes, where it binds to the iron in hemoglobin. In body tissues, oxygen detaches from iron, hemoglobin resumes its former shape, and the resulting deoxyhemoglobin, or reduced hemoglobin, becomes dark red. The released oxygen diffuses from the blood into the tissue fluid and then into tissue cells.
40
What is hematopoiesis?
Hematopoiesis is the process of blood cell formation.
41
Where does hematopoiesis occur in the body?
Hematopoiesis occurs in the red bone marrow.
42
What is the function of erythrocytes?
The function of erythrocytes is to transport oxygen from the lungs to the body tissues and to transport carbon dioxide from the body tissues to the lungs.
43
What is the lifespan of erythrocytes?
The lifespan of erythrocytes is about 120 days.
44
What is the final stage of erythropoiesis?
The final stage of erythropoiesis is the reticulocyte, which is essentially a young erythrocyte that still contains a scant reticulum of clumped ribosomes.
45
What is the function of reticulocytes?
The function of reticulocytes is to enter the bloodstream and mature into erythrocytes.
46
What is the average amount of new blood cells produced by the red bone marrow every day?
The red bone marrow turns out some 30 ml of new blood containing 100 billion new cells every day.
47
What triggers the synthesis and release of erythropoietin?
The drop in normal blood oxygen levels.
48
What are the possible causes of reduced blood oxygen levels that trigger EPO formation?
Reduced numbers of red blood cells due to hemorrhage or excessive RBC destruction, insufficient hemoglobin per RBC, reduced availability of oxygen.
49
What happens when there are too many erythrocytes or excessive oxygen in the bloodstream?
Erythropoietin production is depressed.
50
What controls the rate of erythropoiesis?
The ability of erythrocytes to transport enough oxygen to meet tissue demands.
51
How does bloodborne erythropoietin stimulate red marrow cells?
It causes them to mature more rapidly.
52
What is the role of kidneys in erythropoietin production?
They play the major role in EPO production.
53
What happens when kidney cells become hypoxic?
Oxygen-sensitive enzymes are unable to carry out their normal functions of degrading an intracellular signaling molecule called hypoxia-inducible factor (HIF).
54
What is the consequence of abusing recombinant EPO?
It can cause thick, sticky 'sludge' that can cause clotting, stroke, or heart failure.
55
What stimulates the kidneys to produce erythropoietin?
Low O2 levels in blood.
56
What is the function of erythropoietin in the blood?
To promote erythropoiesis in red bone marrow.
57
Where are aged and damaged red blood cells engulfed and broken down?
By macrophages of spleen, liver, and bone marrow.
58
What happens to the hemoglobin of dying erythrocytes?
It is split off from globin, and its core of iron is salvaged and stored for reuse.
59
What is bilirubin and how is it eliminated from the body?
Bilirubin is a yellow pigment that is released to the blood and eliminated from the body in feces as stercobilin.
60
What are the raw materials required for erythropoiesis?
Nutrients (amino acids, lipids, and carbohydrates), vitamin B12, folic acid, and iron.
61
What is the average lifespan of red blood cells?
100 to 120 days.
62
What happens to the protein (globin) part of hemoglobin?
It is metabolized or broken down to amino acids, which are released to the circulation.
63
Define anemia.
Anemia is a condition in which the blood's oxygen-carrying capacity is too low to support normal metabolism.
64
What are the three groups of causes of anemia?
Blood loss, not enough red blood cells produced, or too many of them destroyed.
65
What is hemorrhagic anemia?
Hemorrhagic anemia is caused by blood loss.
66
What is iron-deficiency anemia?
Iron-deficiency anemia is a result of inadequate intake of iron-containing foods or impaired iron absorption.
67
What is pernicious anemia?
Pernicious anemia is an autoimmune disease that most often affects the elderly.
68
What is renal anemia?
Renal anemia is caused by the lack of EPO, the hormone that controls red blood cell production.
69
What is aplastic anemia?
Aplastic anemia may result from destruction or inhibition of the red marrow by certain drugs and chemicals, ionizing radiation, or viruses.
70
What is hemolytic anemia?
Hemolytic anemia is a condition in which erythrocytes rupture, or lyse, prematurely.
71
What are thalassemias?
Thalassemias are a group of genetic disorders in which one of the globin chains is absent or faulty, and the erythrocytes are thin, delicate, and deficient in hemoglobin.
72
What is sickle-cell anemia?
Sickle-cell anemia is a genetic disorder in which the globin part of hemoglobin is abnormal, causing the erythrocytes produced to be fragile and rupture prematurely.
73
What is polycythemia?
An abnormal excess of erythrocytes that increases blood viscosity, causing it to flow sluggishly.
74
What is blood doping?
Artificially induced polycythemia, practiced by some athletes competing in aerobic events.
75
How does blood doping work?
Some of the athlete’s red blood cells are drawn off and stored. The body quickly replaces these erythrocytes because removing blood triggers the erythropoietin mechanism. Then, when the stored blood is reinfused a few days before the athletic event, a temporary polycythemia results.
76
What are the risks associated with blood doping?
The risk of stroke and heart failure due to high hematocrit and high blood viscosity.
77
What is sickle-cell anemia?
A genetic disorder caused by a single amino acid change in the beta chain of hemoglobin, resulting in sickled erythrocytes.
78
How is sickle-cell anemia treated?
Hydroxyurea, a drug used to treat chronic leukemia, switches the fetal hemoglobin gene back on. This drug dramatically reduces the excruciating pain and overall severity and complications of sickle-cell anemia (by 50%). In children who are severely affected, bone marrow stem cell transplants offer a complete cure, but carry high risks.
79
What is diapedesis?
The process by which white blood cells slip out of the capillary blood vessels and enter areas of the body where they mount inflammatory or immune responses.
80
What are the signals that prompt WBCs to leave the bloodstream at specific locations?
Cell adhesion molecules displayed by endothelial cells.
81
What are neutrophils and what percentage of WBC population do they account for?
Neutrophils are the most numerous white blood cells and account for 50-70% of the WBC population.
82
What is the size of neutrophils compared to erythrocytes?
Neutrophils are about twice as large as erythrocytes.
83
What is the color of neutrophil cytoplasm and why are they called neutral-loving?
Neutrophil cytoplasm has a lilac color due to the presence of granules that take up both basic and acidic dyes. They are called neutral-loving because of this property.
84
What is the role of neutrophils in the body?
Neutrophils are our body's bacteria slayers and their numbers increase explosively during acute bacterial infections. They are chemically attracted to sites of inflammation and are active phagocytes.
85
What is the process of respiratory burst and how do neutrophils kill bacteria?
Respiratory burst is a process during which neutrophils metabolize oxygen to produce potent germ-killer oxidizing substances such as bleach and hydrogen peroxide. Defensin-containing granules merge with the microbe-containing phagosome and form peptide 'spears' that pierce holes in the membrane of the ingested bacteria, causing it to lyse.
86
What are eosinophils and what percentage of leukocytes do they account for?
Eosinophils account for 2-4% of all leukocytes.
87
What is the role of eosinophils in the body?
The most important role of eosinophils is to lead the counter-attack against parasitic worms that are too large to be phagocytized. They also have complex roles in many other diseases including allergies and asthma.
88
What are granulocytes and what are the types of granulocytes?
Granulocytes are a type of leukocyte that contain obvious membrane-bound cytoplasmic granules. The types of granulocytes are neutrophils, eosinophils, and basophils.
89
What is leukocytosis and when does it occur?
Leukocytosis is a condition in which the white blood cell count is over 11,000 cells/μl and it occurs as a normal response to an infection in the body.
90
What are the two major categories of leukocytes and how are they grouped?
The two major categories of leukocytes are granulocytes and agranulocytes. They are grouped on the basis of structural and chemical characteristics.
91
What is the relative percentage of leukocytes in normal blood and what is the order of leukocytes from most abundant to least abundant?
Leukocytes and platelets together account for the remaining 21% of formed elements in normal blood. The order of leukocytes from most abundant to least abundant is neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
92
What are the three sizes of leukocytes based on their diameter?
Small (5-8 μm), medium (10-12 μm), and large (14-17 μm).
93
What is the function of T lymphocytes (T cells)?
Acting directly against virus-infected cells and tumor cells in the immune response.
94
What do B lymphocytes (B cells) give rise to?
Plasma cells, which produce antibodies (immunoglobulins) that are released to the blood.
95
What is the average diameter of monocytes?
18 μm.
96
What happens to circulating monocytes when they leave the bloodstream and enter the tissues?
They differentiate into highly mobile macrophages with prodigious appetites.
97
What is the function of macrophages?
They are actively phagocytic and are crucial in the body's defense against viruses, certain intracellular bacterial parasites, and chronic infections such as tuberculosis.
98
What is leukopoiesis?
The production of white blood cells.
99
What is the function of basophils?
They contain histamine, an inflammatory chemical that acts as a vasodilator and attracts other white blood cells to the inflamed site.
100
What is the most numerous leukocyte in the blood?
Neutrophils.
101
What is the second most numerous leukocyte in the blood?
Lymphocytes.
102
What is the lifespan of monocytes and lymphocytes?
Monocytes may live for several months, whereas the life span of lymphocytes varies from a few hours to decades.
103
What are the two families of hematopoietic factors?
Interleukins and colony-stimulating factors (CSFs).
104
What is the function of hematopoietic factors?
Hematopoietic factors prompt the white blood cell precursors to divide and mature, and enhance the protective potency of mature leukocytes.
105
What is the difference between lymphoid stem cells and myeloid stem cells?
Lymphoid stem cells produce lymphocytes, while myeloid stem cells give rise to all other formed elements.
106
What is the ratio of granulocytes to erythrocytes produced in the body?
The normal ratio of granulocytes to erythrocytes produced is about 3:1.
107
What is leukopenia?
Leukopenia is an abnormally low white blood cell count.
108
What is leukemia?
Leukemia is a group of cancerous conditions involving overproduction of abnormal white blood cells.
109
What are the symptoms of infectious mononucleosis?
The affected individual complains of being tired and achy, and has a chronic sore throat and a low-grade fever.
110
How is the bone marrow stimulated in cancer patients receiving chemotherapy?
Hematopoietic hormones such as EPO and several of the CSFs are used to stimulate the bone marrow of cancer patients who are receiving chemotherapy.
111
What are hematopoietic stem cells also known as?
Hemocytoblasts.
112
What are the two main types of stem cells that hematopoietic stem cells can differentiate into?
Myeloid stem cells and lymphoid stem cells.
113
What are the three types of myeloblasts that granular leukocytes develop from?
Eosinophilic myeloblasts, neutrophilic myeloblasts, and basophilic myeloblasts.
114
What is the precursor for B lymphocytes?
B lymphocyte precursor.
115
What is the precursor for T lymphocytes?
T lymphocyte precursor.
116
What are the two main types of leukocytes?
Granular leukocytes and agranular leukocytes.
117
What are the three types of granular leukocytes?
Eosinophils, neutrophils, and basophils.
118
What is the developmental pathway for granular leukocytes?
Myeloblasts → promyelocytes → myelocytes → band cells → mature cells.
119
What is the developmental pathway for monocytes?
Myeloid stem cell → monoblasts → promonocytes → monocytes.
120
What is the developmental pathway for lymphocytes?
Lymphoid stem cell → B lymphocyte precursor or T lymphocyte precursor → mature B or T lymphocytes.
121
What are platelets?
Fragments of megakaryocytes that help in the clotting process when blood vessels are ruptured or their lining is injured.
122
What is the function of platelets?
To form a temporary plug at the site of injury to help seal the break and prevent blood loss.
123
What regulates the formation of platelets?
A hormone called thrombopoietin.
124
What is a megakaryocyte?
An extraordinarily large cell that gives rise to platelets and has a huge, multilobed nucleus and a large cytoplasmic mass.
125
What is the structure of platelets?
They are roughly disc-shaped with a diameter of 2-4 μm and contain granules that stain purple and contain chemicals that act in the clotting process.
126
What limits clot formation and prevents undesirable clotting?
Several factors, including molecules secreted by endothelial cells lining the blood vessels and anticoagulant proteins in the plasma.
127
What is hemostasis?
The process that stops bleeding when a blood vessel wall breaks.
128
What are the three steps that occur during hemostasis?
Vascular spasm, platelet plug formation, and coagulation (blood clotting).
129
Name the three steps involved in hemostasis.
Vascular spasm, platelet plug formation, and coagulation.
130
What is the role of platelets in hemostasis?
Platelets play a key role in hemostasis by aggregating and forming a plug that temporarily seals the break in the vessel wall. They also help orchestrate subsequent events that form a blood clot.
131
What is the role of von Willebrand factor in platelet plug formation?
Von Willebrand factor stabilizes bound platelets by forming a bridge between collagen and platelets.
132
What are the chemicals released by activated platelets during platelet plug formation?
Activated platelets release adenosine diphosphate (ADP), serotonin, and thromboxane A2.
133
What is coagulation or blood clotting?
Coagulation or blood clotting is the third step in hemostasis that reinforces the platelet plug with fibrin threads that act as a 'molecular glue' for the aggregated platelets.
134
What is the role of clotting factors in coagulation?
Clotting factors work together to form a clot by transforming dissolved blood proteins into fibrin threads. Most clotting factors are plasma proteins synthesized by the liver.
135
What is the role of vitamin K in coagulation?
Vitamin K is required for synthesizing four of the clotting factors involved in coagulation.
136
What happens to the blood clot after hemostasis?
The clot retracts and dissolves as it is replaced by fibrous tissue that permanently prevents blood loss.
137
Name two things that can help cope with the complexity of blood clotting.
Realizing that activation turns clotting factors into enzymes and recognizing that coagulation occurs in three phases.
138
What is the first strategy to cope with the complexity of blood clotting?
Realizing that activation turns clotting factors into enzymes by clipping off a piece of the protein, causing it to change shape.
139
What is the second strategy to cope with the complexity of blood clotting?
Recognizing that coagulation occurs in three phases.
140
How many phases are there in blood clotting?
Three.
141
What are the two pathways that can initiate coagulation?
The intrinsic and extrinsic pathways.
142
What is the common intermediate towards which the intermediate steps of each pathway cascade?
Factor X.
143
What is the slowest step of the blood clotting process?
Formation of prothrombin activator.
144
How long does it take for the clot to form once prothrombin activator is present?
10 to 15 seconds.
145
Why is the intrinsic pathway called intrinsic?
Because the factors needed for clotting are present within (intrinsic to) the blood.
146
What triggers the intrinsic pathway?
Negatively charged surfaces such as activated platelets, collagen, or glass.
147
Why is the intrinsic pathway slower than the extrinsic pathway?
Because it has many intermediate steps.
148
What is the role of platelet-derived growth factor (PDGF) in blood vessel healing?
PDGF stimulates smooth muscle cells and fibroblasts to divide and rebuild the vessel wall.
149
What is the process of fibrinolysis?
Fibrinolysis is the process of removing unneeded clots when healing has occurred.
150
What is the critical natural 'clot buster'?
Plasmin, a fibrin-digesting enzyme.
151
What is the role of tissue plasminogen activator (tPA) in fibrinolysis?
tPA is secreted by endothelial cells in response to the presence of a clot and activates plasminogen to break down the clot.
152
What are the factors that limit normal clot growth?
Swift removal of clotting factors and anticoagulants that prevent clotting.
153
What is the extrinsic pathway of the clotting cascade?
The extrinsic pathway is triggered by exposing blood to tissue factor (TF) found on cells in tissues surrounding the blood vessel, and it bypasses several steps of the intrinsic pathway.
154
What is the end point of phase 3 of the clotting cascade?
The end point of phase 3 is a fibrin mesh that traps blood cells and effectively seals the hole until the blood vessel can be permanently repaired.
155
What is the role of anticoagulants in preventing clotting?
Anticoagulants inhibit clotting and normally dominate to prevent clotting, but when a vessel is ruptured, clotting factor activity in that area increases dramatically and a clot begins to form.
156
What is clot retraction and how does it stabilize the clot?
Clot retraction is a platelet-induced process that further stabilizes the clot by contracting and pulling on the surrounding fibrin strands, squeezing serum from the mass, compacting the clot, and drawing the ruptured edges of the blood vessel more closely together.
157
What are some antithrombic substances secreted by endothelial cells?
Nitric oxide, prostacyclin, and others.
158
What is the role of vasoconstriction in clot formation?
To assist clot formation by preventing the washout of activated clotting factors.
159
What is the role of fibrin in preventing clot enlargement?
By binding thrombin, fibrin effectively acts as an anticoagulant, preventing the clot from enlarging and thrombin from acting elsewhere.
160
What is the role of antithrombin III in preventing clot formation?
Antithrombin III, a protein present in plasma, quickly inactivates any thrombin not bound to fibrin.
161
What is the role of heparin in preventing clot formation?
Heparin, the natural anticoagulant contained in basophil and mast cell granules, inhibits thrombin by enhancing the activity of antithrombin III and protein C.
162
What is thrombocytopenia?
Thrombocytopenia is a condition characterized by a low number of circulating platelets in the blood, which can lead to spontaneous bleeding from small blood vessels all over the body.
163
What can cause thrombocytopenia?
Thrombocytopenia can arise from any condition that suppresses or destroys the red bone marrow, such as bone marrow malignancy, exposure to ionizing radiation, or certain drugs.
164
How is thrombocytopenia treated?
Transfusions of concentrated platelets provide temporary relief from bleeding.
165
What happens when the liver is unable to synthesize its usual supply of clotting factors?
Abnormal and often severe bleeding occurs.
166
What causes impaired liver function?
The causes can range from an easily resolved vitamin K deficiency (common in newborns) to nearly total impairment of liver function (as in hepatitis or cirrhosis).
167
What is the role of vitamin K in clotting factors production?
Liver cells require vitamin K to produce clotting factors.
168
What is hemophilia?
Hemophilia refers to several hereditary bleeding disorders that have similar signs and symptoms.
169
What is the difference between Hemophilia A and Hemophilia B?
Hemophilia A results from a deficiency of factor VIII (antihemophilic factor), while Hemophilia B results from a deficiency of factor IX.
170
Who is more likely to be affected by Hemophilia A and B?
Hemophilia A and B occur primarily in males.
171
What is the role of factor XI in Hemophilia C?
Hemophilia C, a less severe form seen in both sexes, is due to a lack of factor XI.
172
What are the symptoms of hemophilia?
Even minor tissue trauma causes prolonged and potentially life-threatening bleeding into tissues. Commonly, the person’s joints become the blockage and lead to death of those tissues.
173
What is an embolus?
If the thrombus breaks away from the vessel wall and floats freely in the bloodstream, it becomes an embolus (plural: emboli).
174
What is an embolism?
An embolus becomes an embolism when it obstructs a blood vessel.
175
What are the risk factors for thromboembolic disease?
Conditions that roughen the vessel endothelium, such as atherosclerosis or inflammation, cause thromboembolic disease by allowing platelets to gain a foothold. Slowly flowing blood or blood stasis is another risk factor, particularly in bedridden patients and those taking a long flight without moving around.
176
What are some anticoagulant drugs used clinically to prevent undesirable clotting?
Aspirin, heparin, and warfarin are used clinically to prevent undesirable clotting.
177
How does aspirin prevent clotting?
Aspirin is an antiprostaglandin drug that inhibits thromboxane A2 formation (blocking platelet aggregation and platelet plug formation).
178
What is the anticoagulant most used in the hospital?
Heparin, administered in injectable form, is the anticoagulant most used in the hospital (for heart patients undergoing various procedures and to prevent or treat venous thrombosis).
179
What is warfarin and how does it work?
Warfarin interferes with the action of vitamin K in the production of some clotting factors. Because treatment with warfarin is difficult to manage, the introduction of direct oral anticoagulants using other mechanisms has been welcomed.
180
Name the two ways the human cardiovascular system minimizes the effects of blood loss.
Reducing the volume of affected blood vessels and stepping up production of red blood cells.
181
What is the preferred choice for replacing lost blood volume?
Normal saline or a multiple electrolyte solution that mimics the electrolyte composition of plasma.
182
What is disseminated intravascular coagulation (DIC)?
DIC involves both widespread clotting and severe bleeding. Clotting occurs in intact blood vessels and the residual blood becomes unable to clot. Blockage of blood flow accompanied by severe bleeding follows. DIC most commonly happens as a complication of pregnancy or a result of septicemia or incompatible blood transfusions.
183
What is the shelf life of collected blood?
About 35 days.
184
What are packed red blood cells (PRBCs)?
Whole blood from which most of the plasma and leukocytes have been removed.
185
What are the consequences of losing more than 30% of blood volume?
Severe shock, which can be fatal.
186
What is the ABO blood group system?
A system of blood classification based on the presence or absence of specific antigens on the surface of red blood cells.
187
What is the basis of transfusion reactions?
Incompatibility between the donor's blood and the recipient's blood, which triggers an immune response.
188
What is the key difference between prothrombin and thrombin?
Prothrombin is an inactive precursor to thrombin, which is an active enzyme that catalyzes the conversion of fibrinogen to fibrin.
189
What is the preferred treatment for hemophilias?
Transfusions of fresh plasma or injections of the appropriate purified clotting factor.
190
What are agglutinogens and agglutinins in blood groups?
Agglutinogens are antigens present on the surface of red blood cells that determine blood type, while agglutinins are preformed antibodies present in plasma that act against RBCs carrying ABO antigens that are not present on a person’s own red blood cells.
191
What is the most common ABO blood group in North America?
The O blood group.
192
What is the Rh blood typing system named after?
It is named after one Rh antigen (agglutinogen D) that was originally identified in rhesus macaques.
193
What happens if an Rh- person receives Rh+ blood?
The immune system becomes sensitized and begins producing anti-Rh antibodies against the foreign antigen soon after the transfusion.
194
Why is blood typing for ABO and Rh antigens always done before blood transfusion?
Because transfusion reactions can occur when foreign erythrocytes are improperly transfused.
195
How many naturally occurring RBC antigens (blood groups) are found in humans?
At least 30 groups.
196
What is the frequency of AB blood group in the U.S. population?
4%.
197
What is the 'universal donor' blood type?
O blood group.
198
What is the 'universal recipient' blood type?
AB blood group.
199
What is the focus of treatment for transfusion reactions?
Preventing kidney damage by administering fluid and diuretics to increase urine output, diluting and washing out the hemoglobin.
200
Which blood group is considered the universal donor and why?
Group O, because it bears neither the A nor the B antigen.
201
Which blood group is considered the universal recipient and why?
Group AB, because its plasma is devoid of antibodies to both A and B antigens.
202
What is the risk associated with pooled blood transfusions?
Transmission of life-threatening infections, particularly with HIV.
203
What is autologous transfusion?
When the patient predonates his or her own blood, and it is stored and immediately available if needed during surgery.
204
Why is it crucial to determine the blood group of both the donor and the recipient before blood is transfused?
To ensure blood groups are compatible.
205
What is a transfusion reaction?
When the recipient's plasma antibodies attack the donor's red blood cells.
206
What are the consequences of hemoglobin that escapes into the bloodstream during a transfusion reaction?
Circulating hemoglobin passes freely into the kidney tubules, causing cell death and kidney shutdown.
207
What is hemolytic disease of the newborn?
A condition where the mother's antibodies cross through the placenta and destroy the baby's RBCs, producing anemia and hypoxia.
208
What is RhoGAM and why is it used?
RhoGAM is a serum containing anti-Rh antibodies used to prevent sensitization of Rh- women carrying Rh+ babies, which can lead to hemolytic disease of the newborn.
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What is the purpose of blood testing?
To evaluate a person's health and diagnose various disorders.
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What are some examples of blood tests and what information do they provide?
Blood glucose tests indicate how well a diabetic is controlling diet and blood sugar levels. Leukocytosis signals infections
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What is a CMP and CBC?
A CMP (comprehensive metabolic panel) and a complete blood count (CBC) are two batteries of tests that are routinely ordered during physical examinations and before hospital admissions. CMP is a blood chemistry profile that measures various electrolytes, glucose, and markers of liver and kidney disorders. The CBC includes counts of the different types of formed elements, the hematocrit, measurements of hemoglobin content, and size of RBCs.
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What is a bone marrow biopsy used for?
To diagnose disorders of blood-cell formation, leukemia, various marrow infections, and anemias resulting from damage to or failure of the marrow.
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What is an exchange transfusion?
A technique of removing the patient's blood and infusing donor blood until a large fraction of the patient's blood has been replaced
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What is hematoma?
Accumulated, clotted blood in the tissues usually resulting from injury
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What are the most common blood diseases that appear during aging?
Chronic leukemias, anemias, and clotting disorders.
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What is hemoglobin F and why is it important?
Hemoglobin F is a unique hemoglobin that has a higher affinity for oxygen than does adult hemoglobin (hemoglobin A) so that the fetus can effectively transfer oxygen from the mother to itself. It contains two alpha and two gamma (g) polypeptide chains per globin molecule, instead of the paired alpha and beta chains typical of hemoglobin A.
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Define Plasmapheresis.
A process in which blood is removed, its plasma is separated from formed elements, and the formed elements are returned to the patient or donor. It is used to remove antibodies or immune complexes from the blood of individuals with autoimmune disorders and to collect plasma for burn victims and therapeutic use.
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What is Septicemia?
Excessive and harmful levels of bacteria or their toxins in the blood. It is also called blood poisoning.
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What is Hemochromatosis?
An inherited disorder of iron overload in which the intestine absorbs too much iron from the diet. The iron builds up in body tissues, where it oxidizes to form compounds that poison those organs (especially joints, liver, and pancreas).
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What is Myeloproliferative disorder?
It is an all-inclusive term for a group of proliferative disorders (disorders in which normal cell division controls are lost) including leukoerythroblastic anemia involving fibrosis of the bone marrow, polycythemia vera, and leukemia.
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What are the transport functions of blood?
The transport functions of blood include delivering oxygen and nutrients to body tissues, removing metabolic wastes, and transporting hormones.
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What are the regulation functions of blood?
The regulation functions of blood include maintaining body temperature, constant blood pH, and adequate fluid volume.
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What are the protective functions of blood?
The protective functions of blood include hemostasis and prevention of infection.
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What is the composition of blood?
Blood is composed of formed elements and plasma. The hematocrit is a measure of one formed element, erythrocytes, as a percentage of total blood volume.
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What is the function of plasma proteins?
Plasma proteins, most made by the liver, include albumin, globulins, and fibrinogen. Albumin is the most important contributor to the osmotic pressure of blood and carries certain molecules through the blood.
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What are the formed elements of blood?
Formed elements, accounting for 45% of whole blood, are erythrocytes, leukocytes, and platelets. All formed elements arise from hematopoietic stem cells in red bone marrow.
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What are erythrocytes?
Erythrocytes (red blood cells, RBCs) are small, biconcave cells containing large amounts of hemoglobin. They have no nucleus and few organelles. Spectrin allows the cells to change shape as they pass through tiny capillaries.
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What is the major function of erythrocytes?
The major function of erythrocytes is oxygen transport. In the lungs, oxygen binds to iron atoms in hemoglobin molecules, producing oxyhemoglobin. In body tissues, oxygen dissociates from iron, producing deoxyhemoglobin.
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What is erythropoiesis?
Erythropoiesis is the process by which erythrocytes are produced from hematopoietic stem cells and proceed through several stages of differentiation, accumulating hemoglobin and extruding organelles and nucleus.
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What are leukocytes?
Leukocytes are white blood cells (WBCs) that have crucial roles in defending against disease. Two main categories exist: granulocytes and agranulocytes.
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What are platelets?
Platelets are fragments of large megakaryocytes formed in red marrow. When a blood vessel is damaged, platelets form a plug to help prevent blood loss and play a central role in the clotting cascade.
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What is hemostasis?
Hemostasis is the prevention of blood loss. The three major steps of hemostasis are vascular spasm, platelet plug formation, and blood coagulation.
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1. What is the average blood volume in an adult?
5 L.
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2. Which organ releases erythropoietin hormone to promote RBC formation?
Kidney.
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3. Which of the following is true of RBCs?
They contain hemoglobin.
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4. What is the most abundant plasma protein?
Albumin.
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5. Which white blood cells can differentiate into macrophages and lead the attack against parasitic worms?
Monocytes.
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6. Which blood cells do not mature in the bone marrow before being released into the blood?
Lymphocytes.
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7. What is the common intermediate in the intrinsic and extrinsic clotting pathways?
Factor X.
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8. What is the normal pH of the blood?
7.4.
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9. What does AB positive blood type mean?
Agglutinogens A and B are present on red blood cells, and there are no anti-A or anti-B antibodies in plasma, and the blood is Rh+.
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10. List the three major categories of formed elements. Which is least numerous? Which comprise(s) the buffy coat in a hematocrit tube?
a) Red blood cells, white blood cells, and platelets. b) Platelets. c) White blood cells and platelets.
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11. What is a transfusion reaction and why does it happen? What are its possible consequences?
a) A transfusion reaction is an immune response to transfused blood that is not compatible with the recipient's blood type. b) Possible consequences include clumping of red blood cells, blockage of blood vessels, and kidney shutdown.
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12. If you had a high hematocrit, would you expect your hemoglobin determination to be low or high? Why?
High, because hematocrit measures the percentage of RBCs in the blood, and hemoglobin is the protein in RBCs that carries oxygen.
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13. Describe the process of erythropoiesis. What name is given to the immature cell type released to the circulation? How does it differ from a mature erythrocyte?
Erythropoiesis is the process of RBC formation. The immature cell type released to the circulation is called a reticulocyte, which still contains some organelles and ribosomes. A mature erythrocyte has no organelles or ribosomes.
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14. Besides the ability to move by amoeboid motion, what other physiological attributes contribute to the function of white blood cells in the body?
Phagocytosis and the production of antibodies.
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15. If you had a severe infection, would you expect your WBC count to be closest to 5000, 10,000, or 15,000/μl? What is this condition called?
10,000/μl. This condition is called leukocytosis.
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16. Describe the appearance of platelets and state their major function. Why should platelets not be called “cells”?
Platelets are small, irregularly shaped cell fragments. Their major function is to form blood clots. Platelets should not be called “cells” because they lack a nucleus and other organelles.
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17. What is fibrinolysis? What is the importance of this process?
Fibrinolysis is the process of breaking down blood clots. It is important to prevent abnormal clotting and to dissolve clots after they have served their purpose.
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18. How is clot overgrowth usually prevented? List two conditions that may lead to unnecessary (and undesirable) clot formation.
Clot overgrowth is usually prevented by removal of coagulation factors in contact with rapidly flowing blood and by inhibition of activated blood factors. Two conditions that may lead to unnecessary clot formation are thrombocytopenia and liver disease.
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19. What are the abnormalities associated with thalassemia?
Thalassemia is a genetic disorder that results in abnormal hemoglobin production and anemia.
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20. What are the major blood-related problems associated with aging?
Leukemia, anemia, and thromboembolic disease.
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21. What are the fetal hematopoietic sites? When does the red bone marrow become the primary blood-forming site?
The fetal hematopoietic sites include the yolk sac, liver, and spleen. By the seventh month of development, the red bone marrow becomes the primary blood-forming site.
