CH19 Flashcards
1
Q
what are the functions of blood?
A
- transports various substances
- helps regulate several life processes
- affords protection against disease
2
Q
what is the cardiovascular system?
A
Body system that consists of blood, the heart, and blood vessels
3
Q
what is hematology?
A
branch of science concerned with the study of blood, blood-forming tissues, and the disorders associated with them
4
Q
what are the two fluids that help cells obtain oxygen and nutrients or eliminate carbon dioxide and other wastes?
A
- interstitial fluid
- blood
5
Q
what is blood?
A
liquid connective tissue that circulates through the heart, arteries, capillaries, and veins and constitutes the chief means of transport within the body
6
Q
what is blood plasma?
A
liquid extracellular matrix of blood
7
Q
what is interstitial fluid?
A
The portion of extracellular fluid that fills the microscopic spaces between the cells of tissues. Also called intercellular or tissue fluid.
8
Q
how does blood function in transportation?
A
- blood transports inhaled oxygen from the lungs to the cells of the body and carbon dioxide from the body cells to the lungs for exhalation
- It carries nutrients from the digestive canal to body cells and hormones from endocrine glands to other body cells
- Blood also transports heat and waste products to various organs for elimination from the body
9
Q
how does blood function in regulation?
A
- Blood helps regulate pH through the use of buffers
- helps adjust body temperature through the heat-absorbing and coolant properties of the water in blood plasma and its variable rate of flow through the skin
- blood osmotic pressure influences the water content of cells
10
Q
how does blood function in protection?
A
- blood can clot, protects against excessive loss after injury
- white blood cells protect against disease by carrying on phagocytosis
- blood proteins (antibodies, interferons) function against disease
11
Q
what are some physical characteristics of blood?
A
- denser and more viscous than water
- 38°C
- pH is 7.4
- blood volume is 5-6L in average adult male, 4-5L in average adult female
12
Q
what is a complete blood count?
A
- one of the most common blood tests and is often done as part of a regular checkup
- It measures the number and size of red blood cells, hemoglobin, and hematocrit; the number and percentage of each type of white blood cell in a sample of 100 cells; and the number of platelets
13
Q
what is a basic metabolic panel?
A
- group of tests that measure the levels of different chemicals in blood
- glucose, calcium, various electrolytes, blood urea nitrogen, and creatinine
14
Q
what are blood enzyme tests?
A
- used to determine the levels and activity of certain enzymes as indicators of organ damage
- higher levels of creatine kinase and troponin indicate damage to the heart and skeletal muscles
- higher levels of ALT and AST indicate liver damage
15
Q
what is a lipoprotein panel?
A
- tests that assess the risk of heart disease
- total cholesterol, HDL, LDL, and triglycerides
16
Q
what are some blood plasma proteins?
A
- albumins
- globulins
- fibrinogen
17
Q
what are erythrocytes?
A
Blood cell without a nucleus that contains the oxygen‐carrying protein hemoglobin; responsible for oxygen transport throughout the body.
18
Q
what are leukocytes?
A
Nucleated blood cell that is responsible for protecting the body from foreign substances via phagocytosis or immune reactions.
19
Q
what are thrombocytes?
A
A fragment of cytoplasm enclosed in a cell membrane and lacking a nucleus; found in circulating blood; plays a role in hemostasis.
20
Q
what are the types of leukocytes?
A
- neutrophils
- basophils
- eosinophils
agranular:
- monocytes
- lymphocytes
—B lymphocytes
—T lymphocytes
—natural killer cells
21
Q
what is the hematocrit?
A
The percentage of blood made up of RBCs
- Usually measured by centrifuging a blood sample in a graduated tube and then reading the volume of red blood cells and dividing it by the total volume of blood in the sample
22
Q
how does testosterone contribute to higher hematocrit in males?
A
testosterone stimulates synthesis of erythropoietin (EPO), the hormone that in turn stimulates production of RBCs
23
Q
what is anemia?
A
a lower-than-normal number of RBCs
24
Q
what is polycythemia?
A
Disorder characterized by an above‐normal hematocrit (above 55%) in which hypertension, thrombosis, and hemorrhage can occur
25
what are some risks when someone has polycythemia?
- large number of RBCs raises the viscosity of blood, which increases the resistance to flow and makes the blood more difficult for the heart to pump
- contributes to high blood pressure and increased risk of stroke
26
what are some possible causes of polycythemia?
- abnormal increases in RBC production
- tissue hypoxia
- dehydration
- blood doping
- use of erythropoietin by athletes
27
what is the function of water in blood?
- liquid portion of blood
- Solvent and suspending medium.
- Absorbs, transports, and releases heat
28
what is the function of blood plasma proteins in blood?
- most produced by liver
- Responsible for colloid osmotic pressure
- Major contributors to blood viscosity
- Transport hormones (steroid), fatty acids, and calcium
- Help regulate blood pH
29
what is the function of albumin in blood?
- smallest and most numerous plasma proteins
- maintains osmotic pressure
30
what is the function of globulins in blood?
- large proteins (plasmocytes produce immunoglobulins)
- Alpha and beta globulins **transport** iron, lipids, and fat-soluble vitamins
- immunoglobulins attack viruses and bacteria
31
what are plasmocytes?
cells derived from certain blood cells that produce gamma globulins
32
what are fibrinogens?
- large plasma protein
- essential role in blood clotting
33
what is the function of electrolytes in blood?
- Help maintain osmotic pressure and play essential roles in cell functions
- Na+, K+, Ca2+
- Cl-, HPO4 2-, SO4 2-, HCO3 -
34
what is the function of nutrients in blood?
- essential roles in cell functions, growth, development
- Products of digestion, such as amino acids, glucose, fatty acids, glycerol, vitamins, and minerals
35
does nitrogen have a function in blood?
N2 has no known function *in blood*
*in blood vessels*, NO (NOT N2) causes vasodilation, an increase in blood vessel diameter that occurs when the smooth muscle in the vessel wall relaxes. Vasodilation improves blood flow and enhances oxygen delivery to cells near the site of NO release
36
Which formed elements of the blood are cell fragments?
platelets are fragments of megakaryocytes
37
how do RBC and platelet levels in blood remain steady?
Negative feedback systems regulate the total number of RBCs and platelets in circulation, and their numbers normally remain steady
38
what is hemopoiesis?
process by which the formed elements of blood develop
39
where does hemopoiesis occur before birth?
in the umbilical vesicle of an embryo and later in the liver, spleen, thymus, and lymph nodes of a fetus
40
where does hemopoiesis occur in the last 3 months before birth and after birth and throughout life?
red bone marrow
41
where is red bone marrow located?
- in axial skeleton
- pectoral and pelvic girdles
- proximal epiphyses of humerus and femur
42
what is the percentage of multipotent stem cells in red bone marrow cells?
0.05% - 0.1%
43
what are hemocytoblasts/
multipotent stem cells?
Immature stem cell in red bone marrow that gives rise to a group of closely related cells
- derive from **mesenchyme**
44
what happens to blood cell production in red bone marrow as an individual ages?
- the rate of blood cell formation decreases
- red bone marrow in the medullary cavity of long bones replaced by yellow bone marrow
45
can yellow bone marrow revert to red bone marrow?
yes, under certain conditions such as sever bleeding
- blood-forming stem cells from red bone marrow move into yellow bone marrow, which is then repopulated by multipotent stem cells
46
can multipotent stem cells directly differentiate into different blood cells?
No, must differentiate into two further types of stem cells: myeloid and lymphoid stem cells
47
what are myeloid stem cells?
stem cells that begin their development in red bone marrow and give rise to red blood cells, platelets, monocytes, neutrophils, eosinophils, basophils, and mast cells
48
what are lymphoid stem cells?
stem cells that begin their development in red bone marrow and complete it in lymphoid tissues (such as thymus)
- gives rise to lymphocytes, natural killer cells, B cells, T cells
49
how can you tell the difference between myeloid and lymphoid stem cells?
- cannot be distinguished **histologically** because they resemble lymphocytes
- they can be distinguished by their distinctive cell identity markers in their plasma membranes
50
what are progenitor cells?
cells no longer capable of reproducing themselves and are committed to giving rise to more specific formed elements in blood
- includes colony-forming units (CFUs)
51
how can you tell the difference between progenitor cells?
- cannot be distinguished **histologically** because they resemble lymphocytes
- they can be distinguished by their distinctive cell identity markers in their plasma membranes
52
whart is bone marrow aspiration?
withdrawal of a small amount of red bone marrow with a fine needle and syringe
53
what is bone marrow biopsy?
removal of a core or cylindrical sample of red bone marrow with a larger needle
54
where is bone marrow typically taken from?
iliac crest of the hip bone
55
what are precursor cells?
immature cells that develop into actual formed elements of the blood over several cell divisions
- monoblasts → monocytes
- eosinophilic myeloblasts → eosinophils
56
what are hemopoietic growth factors?
hormones that regulate the differentiation and proliferation of particular progenitor cells
57
what is erythropoietin?
A hormone released by the juxtaglomerular cells of the kidneys that stimulates red blood cell production
58
why does kidney failure affect the blood? (in the context of EPO)
with renal failure, EPO release slows (juxtaglomerular cells do not release EPO) and RBC production becomes inadequate
results in decreased hematocrit and a decreased ability to deliver oxygen to body tissues
59
what is thrombopoietin?
a hormone produced by the liver that stimulates the formation of platelets from megakaryocytes
60
what are cytokines?
- small glycoproteins that are typically produced by cells such as red bone marrow cells, leukocytes, macrophages, fibroblasts, and endothelial cells
- generally act as local hormones
- stimulate proliferation of progenitor cells in red bone marrow
- regulate the activities of cells involved in nonspecific defenses and immune responses
61
what are colony-stimulating factors?
One of a group of molecules that stimulates development of white blood cells
62
what are interleukins?
One of a group of molecules that stimulates development of white blood cells
63
what is hemoglobin?
A substance in red blood cells consisting of the protein globin and the iron‐containing red pigment heme that transports most of the oxygen and some carbon dioxide in blood
64
what is the rate of RBCs entering circulation?
2 million RBCs per second
65
what property of RBC plasma membranes allow them to deform without rupturing?
their plasma membranes are both strong and flexible
66
why can RBCs not reproduce or carry on extensive metabolic activities?
they do not have a nucleus and other organelles
67
where are the hemoglobin molecules in RBCs?
they are suspended in the RBC's cytosol
68
do RBCs use up the oxygen they transport?
No, because RBCs lack mitochondria and generate ATP anaerobically
69
why are RBCs being biconcave important?
A biconcave disc has a much greater surface area for the diffusion of gas molecules into and out of the RBC
70
how much hemoglobin molecules are in one RBC?
280 million hemoglobin molecules per 1 RBC
71
what are the proteins that compose a hemoglobin molecule?
globin molecules
(2 alpha globins and 2 beta globins)
72
what is heme?
ringlike nonprotein pigment that has a Fe2+ at its center which can **reversibly** bind and unbind to one oxygen molecule
73
describe how carbonic anhydrase catalyzing CO2 + H2O → H2CO3 is significant
- allows 70% of CO2 to be transproted in blood plasma from tissue cells to the lungs in the form of HCO3-
- serves as an important pH buffer in extracellular fluid
74
why do RBCs have a short lifespan?
- wear and tear to their plasma mebranes
- cannot synthesize new components to replace damaged ones due to no nucleus and organelles
75
how are RBCs recycled?
1. Macrophages in the spleen, liver, or red bone marrow phagocytize ruptured and worn-out red blood cells
2. The globin and heme portions of hemoglobin are split apart
3. Globin is broken down into amino acids, which can be reused to synthesize other proteins
4. Iron is removed from the heme portion in the form of Fe3+, which associates with **transferrin**, a transporter for Fe3+ in the bloodstream
5. In muscle fibers, liver cells, and macrophages of the spleen and liver, Fe3+ detaches from **transferrin** and attaches to an iron-storage protein **ferritin**
6. On release from a storage site or absorption from the digestive canal, Fe3+ reattaches to transferrin
7. The Fe3+/transferrin complex is then carried to red bone marrow, where RBC precursor cells take it up through receptor-mediated endocytosis for use in hemoglobin synthesis (Vit B12, amino acids, and iron needed)
8. Erythropoiesis in red bone marrow results in the production of red blood cells, which enter the circulation
9. When iron is removed from heme, the non-iron portion of heme is converted to **biliverdin** (green pigment) and then into **bilirubin** (yellow-orange pigment)
10. **Bilirubin** enters the blood and is transported to the liver
11. Within the liver, **bilirubin** is released by liver cells into bile, which passes into the small intestine and then into the large intestine
12. In the large intestine, bacteria convert **bilirubin** into **urobilinogen**
13. Some **urobilinogen** is absorbed back into the blood, converted to **urobilin** (yellow pigment) and excreted in urine
14. Most **urobilinogen** is eliminated in feces in the form of **stercobilin** (brown pigment) which gives feces its characteristic color
76
ruptured blood cells are destroyed by what kinds of cells?
phagocytic macrophages
77
what is transferrin?
plasma protein that transports the iron removed from heme in the bloodstream
78
what is ferritin?
plasma protein that stores the iron removed from heme
79
what colour is biliverdin?
green
80
what colour is bilirubin?
yellow-orange
81
what is urobilinogen?
precursor to urobilin
82
what colour is urobilin?
yellow
83
what colour is stercobilin?
brown
84
how do transferrin and ferritin as protection for the body?
they "escort" iron around the body, free iron ions can damage molecules in cells or in the blood
85
what is iron overload?
amount of iron present in body builds up, transferrin and ferritin become saturated with iron ions, and free iron level rises
86
what are common consequences of iron overload?
disease of the liver, heart, pancreatic islets, gonads
87
what is a reticulocyte?
a proerythroblast near the end of its development sequence that ejects its nucleus
- retains some mitochondria, ribosomes, and ER
- still in red bone marrow
- becomes an RBC after 1-2 days in circulation
88
how is rate of erythropoiesis measured?
reticulocyte count
89
describe the negative feedback loop that occurs when oxygen delivery to kidneys and other tissues is decreased
Receptors: kidney cells
Input: detect low O2, increase erythropoietin in blood
control center: proerythroblasts in RBM mature into reticulocytes
output: more reticulocytes enter circulation
effectors: more RBCs in circulation
Response: increased oxygen delivery to tissues
90
what may reduce oxygen delivery to body tissues?
- lower oxygen content of air at high altitudes
- anemia
- circulatory problems
91
why are older neutrophils called *polymorphonuclear leukocytes*?
number of nuclear lobes increases as neutrophil age increase
older neutrophils have several differently shaped nuclear lobes
92
what are the different types of macrophages?
resting macrophages: reside in a particular tissue
wandering macrophages: roam tissues and gather at sites of infection/inflammation
93
what are major histocompatibility antigens?
proteins protruding from plasma membranes of WBCs and other nucleated cells in body that act as cell identity markers
94
what is leukocytosis?
- an increase in the number of WBCs above 10,000/μL
- a normal protective response to stresses such as invading microbes, strenuous exercise, anesthesia, and surgery
95
what is leukopenia?
- An abnormally low level of white blood cells (below 5000/μL)
- never beneficial
- may be caused by radiation, shock, and certain chemotherapeutic agents
96
can granular leukocytes and monocytes return to the bloodstream after leaving it to fight injury and infection?
no, they collect at sites of pathogen invasion or inflammation and stay there
97
what is emigration?
also called *diapedesis*
process whereby white blood cells leave the bloodstream by rolling along the endothelium, sticking to it, and squeezing between the endothelial cells
98
what are adhesion molecules?
molecules that help WBCs stick to the endothelium
99
what are selectins?
adhesion molecules that stick to carbohydrates on the surface of neutrophils, causing them to slow down and roll along the endothelial surface
100
what are integrins?
adhesion molecules that tether neutrophils to the endothelium and assist their movement through the blood vessel wall and into the interstitial fluid of the injured tissue
101
what is chemotaxis?
phagocytes such as **neutrophils** and **macrophages** attracted to chemicals released by microbes and inflamed tissues
102
what are kinins?
specialized products of damaged tissues that help provide stimuli for chemotaxis (attraction of phagocytes)
103
In what way is the “traffic pattern” of lymphocytes in the body different from that of other WBCs?
lymphocytes are the only leukocytes that can leave the blood stream into tissues and **return** or **recirculate**
Only 2% of the total lymphocyte population is circulating in the blood at any given time; the rest is in lymph plasma and organs such as the skin, lungs, lymph nodes, and spleen
104
list the leukocytes from MOST numerous to LEAST numerous
Never Let Monkeys Eat Bananas;
1 Neutrophils
2 Lymphocytes
3 Monocytes
4 Eosinophils
5 Basophils
105
what is the function of neutrophils
phagocytosis of microbes that cause tissue destruction
106
what do neutrophils unleash into their cytoplasm after engulfing a pathogen?
- lysozyme - destroys certain bacteria
- strong oxidants - O2- anion, H2O2, OCl-
- defensins
107
what are defensins?
proteins that exhibit a broad range of antibiotic activity against bacteria and fungi
- Within a neutrophil, vesicles containing defensins merge with phagosomes containing microbes
- Defensins form peptide “spears” that poke holes in microbe membranes; the resulting loss of cellular contents kills the invader
108
what is the function of eosinophils?
- release histamine to combat effects of histamine and allergic rxns
- kill parasitic worms
- phagocytize antigen-antibody complexes
109
what does a high eosinophil count indicate?
- allergic condition
- parasitic infection
110
what is the function of basophils?
- release granules containing heparin, histamine, serotonin, intensifying inflammatory rxns
- involved in allergic rxns
- similar in function to mast cells
111
what are mast cells?
- connective tissue cells that originate from multipotent stem cells in red bone marrow
- release substances involved in inflammation, including heparin, histamine, and proteases
- widely dispersed in the body, particularly in connective tissues of the skin and mucous membranes of the respiratory and digestive canal
112
what is the function of B lymphocytes?
particularly effective in destroying microbes and inactivating their toxins
113
what is the function of T lymphocytes?
attack infected body cells and tumor cells, and are responsible for the rejection of transplanted organs
114
what is the function of natural killer cells?
attack a wide variety of infected body cells and certain tumor cells
115
what is the function of monocytes?
- similar to neutrophils
- phagocytize microbes and other pathogens
- On their arrival, monocytes enlarge and differentiate into wandering macrophages, which clean up cellular debris and microbes by phagocytosis after an infection
116
what does low neutrophil count indicate?
Radiation exposure, drug toxicity, vitamin B12 deficiency, systemic lupus erythematosus.
117
what does high neutrophil count indicate?
Bacterial infection, burns, stress, inflammation.
118
what does low lymphocyte count indicate?
Prolonged illness, HIV infection, immunosuppression, treatment with cortisol.
119
what does high lymphocyte count indicate?
Viral infections, some leukemias, infectious mononucleosis.
120
what does low monocyte count indicate?
Bone marrow suppression, treatment with cortisol.
121
what does high monocyte count indicate?
Viral or fungal infections, tuberculosis, some leukemias, other chronic diseases.
122
what does low eosinophil count indicate?
Drug toxicity, stress, acute allergic reactions
123
what does high eosinophil count indicate?
Allergic reactions, parasitic infections, autoimmune diseases.
124
what does low basophil count indicate?
Pregnancy, ovulation, stress, hypothyroidism
125
what does high basophil count indicate?
Allergic reactions, leukemias, cancers, hypothyroidism
126
how do platelets help stop blood loss?
1. by forming platelet plug
2. granules in cytoplasm contain chemicals that promote blood clotting once released
127
what cells remove aged and dead platelets?
fixed macrophages in the spleen and liver
128
how are platelets used to treat chronic injuries to tendons, ligaments, and skeletal muscles?
Platelets have tissue-regenerating qualities because they contain a number of growth factor proteins that encourage fibroblasts to increase their production of collagen fibers and extracellular matrix components and to increase new blood vessel formation
129
what is a PRP?
- *platelet-rich plasma*
- blood is withdrawn from a patient and the whole blood is centrifuged
- buffy coat is injected into the patient's injury site to promote tissue regeneration
130
what is a bone marrow transplant?
replacement of cancerous or abnormal red bone marrow with healthy red bone marrow in order to establish normal blood cell counts
131
what is graft-vs-host disease?
transplanted red bone marrow may produce T cells that attack the recipient’s tissues
132
what is a cord-blood transplant?
Stem cells may be obtained from the umbilical cord shortly after birth. The stem cells are removed from the cord with a syringe and then frozen
133
what are some advantages to stem cells from the umbilical cord over those obtained from red bone marrow?
1. They are easily collected following permission of the newborn’s parents
2. They are more abundant than stem cells in red bone marrow
3. They are less likely to cause graft-versus-host disease, so the match between donor and recipient does not have to be as close as in a bone marrow transplant. This provides a larger number of potential donors.
4. They are less likely to transmit infections.
5. They can be stored indefinitely in cord-blood banks.
134
what is hemostasis?
a sequence of responses that stops bleeding
135
what are the three mechanisms of hemostasis?
1. vascular spasm
2. platelet plug formation
3. blood clotting/coagulation
136
what is hemorrhage?
Bleeding; the escape of blood from blood vessels, especially when the loss is profuse
137
what happens in vascular spasm?
when arteries or arterioles are damaged, the circularly arranged smooth muscle in their walls contracts immediately, constricting the diameter of the blood vessel
- reduces blood loss for several minutes to several hours
- caused by reflexes initiated by pain receptors
- caused by damage to smooth muscle
- caused by substances released from activated platelets
138
what is platelet-derived growth factor?
hormone that can cause proliferation of vascular endothelial cells, vascular smooth muscle fibers, and fibroblasts to help repair damaged blood vessel walls
139
how does platelet plug formation occur?
1. platelet adhesion
2. platelet release reaction
3. platelet aggregation
140
what happens in platelet adhesion?
platelets contact and stick to parts of a damaged blood vessel, such as collagen fibers of the connective tissue underlying the damaged endothelial cells
141
what happens in platelet release reaction?
- platelets become activated
- extend many projections that enable them to contact and interact with one another (form **pseudopods**)
- they begin to liberate the contents of their vesicles
142
what happens in platelet aggregation?
- release of ADP makes other platelets in area sticky, adhering to originally activated platelets
- accumulation and attachment of numerous platelets form a platelet plug
143
what is blood serum?
blood plasma without the clotting proteins
the remaining liquid after blood that is drawn from body thickens and blood clots
144
what is a blood clot?
A gel that consists of the formed elements of blood trapped in a network of insoluble protein fibers called fibrin
145
what is thrombosis?
clotting in an undamaged blood vessel due to blood clotting too easily
146
where are blood clotting factors made?
hepatocytes in the liver
147
what are the three stages of blood clotting?
1. formation of prothrombinase
2. prothrombin → thrombin
3. fibrinogen → fibrin
148
what is the extrinsic pathway of blood clotting?
- thromboplastin leaks into the blood from cells **outside** blood vessels and initiates prothrombinase formation
- occurs rapidly
149
what is thromboplastin?
tissue protein released from surfaces of damaged cells
- begins sequence of rxns that activates clotting factor X in presence of Ca2+
150
what is the intrinsic pathway of blood clotting?
- outside tissue damage is not needed
- blood can come in contact with collagen fibers in the connective tissue around the endothelium of the blood vessel if endothelial cells become roughened or damaged
- trauma to endothelial cells causes damage to platelets, resulting in the release of phospholipids by the platelets
- Contact with collagen fiber activates clotting factor XII, eventually activating clotting factor X
- prothrombinase is activated by X and V
151
what is the common pathway of blood clotting?
- begins when prothrombinase is formed
- prothrombinase + Ca2+ catalyze prothrombin → thrombin
- thrombin + Ca2+ catalyze fibrinogen → fibrin
152
what are the two positive feedback effects of thrombin?
- accelerates prothrombinase formation (w/ factor V)
- activates platelets, reinforces their aggregation and release of platelet phospholipids
153
what is clot retraction?
- consolidation or tightening of the fibrin clot
- fibrin threads attached to the damaged surfaces of the blood vessel gradually contract as platelets pull on them
- as the clot retracts, it pulls the edges of the damaged vessel closer together, decreasing the risk of further damage
- some blood serum can escape between the fibrin threads, but the formed elements in blood cannot
154
what is the role of vitamin K in clotting?
- required for the synthesis of four clotting factors
- not involved in actual clot formation
155
what is the function of the fibrinolytic system?
dissolves small, inappropriate clots; it also dissolves clots at a site of damage once the damage is repaired
- helpful b/c small clots tend to form randomly many times a day in undamaged blood vessels
156
what is fibrinolysis?
dissolution of a clot
157
what does plasmin do?
can dissolve clots by digesting fibrin threads and inactivating fibrinogen, prothrombin, and factors V and XII
158
what blood clotting factors are activated in the intrinsic pathway?
- IV
- V
- VIII
- IX
- X
- XI
- XII
159
what blood clotting factors are activated in the extrinsic pathway?
- III
- IV
- V
- VII
- X
160
what blood clotting factors are activated in the common pathway?
- I
- II
- IV
- XIII
161
why does a clot not extend beyond a wound site into the general circulation?
fibrin absorbs thrombin into the clot, preventing thrombin from enacting its positive feedback effects on blood clotting
- because of the dispersal of some of the clotting factors by the blood, their concentrations are not high enough to bring about widespread clotting
162
what are anticoagulants?
A substance that can delay, suppress, or prevent the clotting of blood
163
what is heparin?
an anticoagulant produced by mast cells and basophils that combines with antithrombin and blocks thrombin from blood clotting
164
what is a thrombosis?
clotting in an unbroken blood vessel, usually a vein
165
what is a thrombus?
clot formed in an unbroken blood vessel
166
what is an embolus?
blood clot, bubble of air, fat from broken bones, or a piece of debris transported by the bloodstream
167
what is a pulmonary embolism?
An embolus that breaks away from an arterial wall and lodges in the lungs
168
what are agglutinins?
antibodies that react with agglutinogens (antigens)
169
why can antibodies not cross the placenta?
they are large, hence why ABO incompatibility btwn a mom and fetus rarely causes problems
170
what is a transfusion?
- the transfer of whole blood or blood components (red blood cells only or blood plasma only) into the bloodstream or directly into the red bone marrow
- most given to alleviate anemia, to increase blood volume, or to improve immunity
171
what is agglutination?
clumping of blood cells due to an incompatibility btwn agglutinin and agglutinogen
172
what is hemolysis?
The escape of hemoglobin from the interior of a red blood cell into the surrounding medium; results from disruption of the cell membrane by toxins or drugs, freezing or thawing, or hypotonic solutions
- liberated hemoglobin may cause kidney damage by clogging the filtration membranes
173
what two reactions can occur when a type B donor gives a type A recipient blood?
1. the anti-B antibodies in the recipient’s blood plasma can bind to the B antigens on the donor’s red blood cells, causing **agglutination** and hemolysis of the red blood cells
anti-B antibodies > B antigens
2. the anti-A antibodies in the donor’s blood plasma can bind to the A antigens on the recipient’s red blood cells, a **less serious reaction** because the donor’s anti-A antibodies become so diluted in the recipient’s blood plasma that they **do not cause significant agglutination** and hemolysis of the recipient’s RBCs
anti-A antibodies < A antigens
174
what is the difference between agglutination and hemolysis?
Agglutination refers to clumping of erythrocytes due to the binding of antibodies to antigens on the surface of the erythrocytes; hemolysis is the lysis of erythrocytes, which usually occurs when antigen-antibody complexes activate the complement pathway.
175
what blood type are the universal recipients?
Type-AB
- no antibodies to attack antigens on donated RBCs
176
what blood type are the universal donors?
Type-O
- neither A nor B antigens on their RBCs
- may receive only type O blood
177
what is hemolytic disease of the newborn?
A hemolytic anemia of a newborn child that results from the destruction of the infant’s erythrocytes (red blood cells) by antibodies produced by the mother; usually the antibodies are due to an Rh blood type incompatibility
- also called *erythroblastosis fetalis*
178
why are firstborn Rh+ babies with a Rh- mother usually not affected?
Because the greatest possibility of fetal blood leakage into the maternal circulation occurs at delivery
179
what are RhoGAM injections?
injection of anti-Rh antibodies given to prevent HDN
- received before delivery and soon after ever delivery
- antibodies bind to and *inactivate the fetal Rh antigens before the mother’s immune system can respond* to the foreign antigens by producing her own anti-Rh antibodies
180
What is antiserum?
solution that contains antibodies
181
what is the most common type of anemia?
iron-deficiency anemia; caused by inadequate absorption of iron, excessive loss of iron, increased iron requirement, or insufficient intake of iron
- Women are at greater risk for iron-deficiency anemia due to menstrual blood losses and increased iron demands of the growing fetus during pregnancy
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what is megaloblastic anemia?
red bone marrow produces large, abnormal red blood cells (megaloblasts); caused by inadequate vitamin B12 or folic acid
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what is pernicious anemia?
Insufficient hemopoiesis resulting from an inability of the stomach to produce intrinsic factor, which is needed for absorption of vitamin B12 in the small intestine
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what is haemorrhagic anemia?
Excessive loss of RBCs through bleeding resulting from large wounds, stomach ulcers, or especially heavy menstruation
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what is hemolytic anemia?
- RBC plasma membranes rupture prematurely
- hemoglobin pours into the blood plasma and may damage the filtering units (glomeruli) in the kidneys
- may result from inherited defects such as abnormal red blood cell enzymes, or from outside agents such as parasites, toxins, or antibodies from incompatible transfused blood
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what is thalassemia?
- Deficient synthesis of hemoglobin
- hereditary hemolytic anemias
- small, pale, short-lived RBCs
- occurs primarily in popns bordering Mediterranean sea
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what is aplastic anemia?
- destruction of red bone marrow
- caused by toxins, gamma radiation, medications inhibiting enzymes needed in hemopoiesis
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what is Hb-S?
abnormal kind of hemoglobin in RBCs of people suffering sickle cell disease
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What are some symptoms of sickle cell disease?
anemia, jaundice, bone pain, shortness of breath, rapid heart rate, abdominal pain, fever, and fatigue
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why are sickle cell genes primarily found among populations that live in the malaria belt?
people with one defective gene and have sickle cell trait give higher-than-average resistance to malaria, offers survival benefit
- The genes responsible for the tendency of the RBCs to sickle also alter the permeability of the plasma membranes of sickled cells, causing potassium ions to leak out. Low levels of potassium kill the malaria parasites that may infect sickled cells
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what is hemophilia?
- inherited, sex-linked deficiency of clotting in which bleeding may occur spontaneously or after only minor trauma
- oldest known hereditary bleeding disorder
- usually affects males
- characterized by spontaneous or traumatic subcutaneous and intramuscular hemorrhaging, nosebleeds, blood in the urine, and hemorrhages in joints that produce pain and tissue damage
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what is leukemia?
- a group of red bone marrow cancers in which abnormal white blood cells multiply uncontrollably
- accumulation of the cancerous white blood cells in red bone marrow interferes with the production of red blood cells, white blood cells, and platelets
- oxygen-carrying capacity of the blood is reduced, an individual is more susceptible to infection, and blood clotting is abnormal
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what is lymphoblastic leukemia?
leukemia involving lymphoid stem cells
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what is myelogenous leukemia?
leukemia involving myeloid stem cells
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Shilpa has recently been on broad-spectrum antibiotics for a recurrent urinary bladder infection. While slicing vegetables, she cut herself and had difficulty stopping the bleeding. How could the antibiotics have played a role in her bleeding?
The broad-spectrum antibiotics may have destroyed the bacteria that caused Shilpa’s urinary bladder infection but also destroyed the naturally occurring large intestine bacteria that produce vitamin K. Vitamin K is required for the synthesis of four clotting factors (II, VII, IX, and X). Without these clotting factors present in normal amounts, Shilpa will experience clotting problems until the intestinal bacteria reach normal levels and produce additional vitamin K.
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Mrs. Brown is in renal failure. Her recent blood tests indicated a hematocrit of 22. Why is her hematocrit low? What can she be given to raise her hematocrit?
Mrs. Brown’s kidney failure is interfering with her ability to produce erythropoietin (EPO). Her physician can prescribe Epoetin alfa, a recombinant EPO, which is very effective in treating the decline in RBC production with renal failure.
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Thomas has hepatitis, which is disrupting his liver functions. What kinds of symptoms would he be experiencing based on the role(s) of the liver related to blood?
A primary problem Thomas may experience is with clotting. Clotting time becomes longer because the liver is responsible for producing many of the clotting factors and clotting proteins such as fibrinogen. Thrombopoietin, which stimulates the formation of platelets, is also produced in the liver. In addition, the liver is responsible for eliminating bilirubin, produced from the breakdown of RBCs. With a malfunctioning liver, the bilirubin will accumulate, resulting in jaundice. In addition, there can be decreased concentrations of the plasma protein albumin, which can affect blood pressure.
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the function of fibrinolysin is to:
dissolve clots by digesting fibrin threads
Fibrinolysin, or plasmin, is the activated form of plasminogen. It is an active plasma enzyme that can dissolve a clot by digesting the fibrin threads and inactivating substances like clotting factors.
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Which parts of the world have high incidences of sickle-cell disease?
Sickle cell disease is found primarily along populations (or their descendants) that live in the malaria belt around the world. This includes part of mediterranean Europe, sub-Saharan Africa, and tropical Asia.
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In order for a person to have sickle-cell disease, how much defective hemoglobin genes do they need?
Sickle cell disease is defined by an abnormal kind of hemoglobin in which the red blood cells contain Hb-S. This disease is inherited. People with **two sickle cell genes** have severe anemia whereas those with only one defective gene have a sickle cell trait.
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what is the correct sequence of steps involved in the formation of a platelet plug?
platelet adhesion
platelet release reaction
platelet aggregation
platelet plug
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A man of Greek ancestry goes to his doctor with the following symptoms. He is very tired all of the time. He has difficulty catching his breath after even mild exercise. What is a likely diagnosis?
He has symptoms consistent with **thalassemia**, which is common in individuals from the Mediterranean Sea region. This is a form of hereditary hemolytic anemia.
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Graft-versus-host-disease is caused by?
Graft-versus-host disease is when transplanted tissue produces T cells that attack the recipient's tissues (donor white blood cells attacking host tissue). Due to this, transplant patients must take immunosuppressive drugs for life to inhibit immune system activity.
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