Chapter 17 - Blood Flashcards
1
Q
Blood consists of ___ and ____.
A
plasma; formed elements
2
Q
Formed elements are:
A
living blood cells suspended in plasma
3
Q
The different formed elements in blood are:
A
- erythrocytes
- leukocytes
- platelets
4
Q
Erythrocytes are
A
red blood cells
5
Q
Leukocytes are
A
white blood cells
6
Q
Centrifugal spinning of a blood sample in a test tube yields three layers:
A
- Plasma on top (~55%)
- Buffy coat (WBCs and platelets) (< 1%)
- Erythrocytes on bottom (~45%)
7
Q
The hematocrit is:
A
The percent of blood volume that is RBCs
8
Q
Blood colour varies with oxygen content. If it has high O2, the colour is
A
scarlet
9
Q
Blood colour varies with oxygen content. If it has low O2, the colour is
A
dark red
10
Q
The pH of blood is:
A
7.35-7.45
11
Q
Blood is approximately how much of body weight?
A
~8%
12
Q
The different functions of blood include:
A
- Distributing substances
- Regulating blood levels of substances
- Protection
13
Q
Different distribution functions of blood:
A
- Delivering O2 and nutrients to body cells
- Transporting metabolic wastes to lungs and kidneys for elimination
- Transporting hormones from endocrine organs to target organs
14
Q
Different regulation functions of blood:
A
- Maintaining body temperature by absorbing and distributing heat
- Maintaining normal pH using buffers
- Maintaining adequate fluid volume in circulatory system
15
Q
Different protection functions of blood:
A
- Preventing blood loss
2. Preventing infection
16
Q
____ and ____ initiate clot formation.
A
Plasma proteins; platelets
17
Q
Blood plasma as over 100 dissolved solutes. The different solutes are
A
- nutrients
- gases
- hormones
- wastes
- plasma proteins
- inorganic ions
18
Q
The most abundant solutes in the blood plasma are
A
plasma proteins
19
Q
Plasma proteins:
A
- remain in blood; are not taken up by cells
2. are produced mostly by liver
20
Q
Plasma proteins consist of:
A
- 60% albumin
- 36% globulins
- 4% fibrinogen
21
Q
The different functions of albumin are:
A
- Substance carrier
- Blood buffer
- Major contributor of plasma osmotic pressure
22
Q
Platelets are _____.
A
cell fragments
23
Q
Most formed elements survive in the bloodstream for:
A
only a few days
24
Q
Most blood cells originate in:
A
the bone marrow
25
Physical characteristics of erythrocytes:
1. Biconcave shape--huge surface area relative to volume
2. 97% hemoglobin for gas (mostly O2) transport
3. anucleate
4. no organelles or mitochondria
5. contains plasma membrane protein spectrin and other proteins
6. do not consume O2 they transport
26
ATP production in RBCs is through ___ means.
anaerobic
27
This plasma protein provides flexibility to RBCs to change shape.
spectrin
28
The hemoglobin structure consists of:
1. globin
| 2. heme pigment
29
Globin is composed of:
2 alpha and 2 beta chains (4 polypeptide chains)
30
____ is bonded to each globin chain in hemoglobin.
heme pigment; gives blood its red colour
31
Heme and hemoglobin's functions:
1. heme has a central iron atom that binds one O2
| 2. each hemoglobin molecule can transport four O2
32
Each RBC contains approximately ____ hemoglobin molecules.
250 million
33
O2 loading in lungs produces:
oxyhemoglobin (ruby red)
34
O2 unloading in tissues produces:
deoxyhemoglobin (reduced hemoglobin) (dark red)
35
When CO2 loads in tissues:
20% of CO2 in blood binds to hemoglobin, which produces carbaminohemoglobin
36
Blood cells form in _____.
red bone marrow
37
Blood cell formation in red bone marrow is composed of:
1. reticular connective tissue
| 2. blood sinusoids
38
Hematopoiesis:
blood cell formation
39
Blood cell formation is found in:
1. axial skeleton
2. girdles
3. proximal epiphyses of humerus and femur
40
New blood cells in hematopoiesis enter:
blood sinusoids
41
Aspects of hematopoietic stem cells (hemocytoblasts) in hematopoiesis:
1. they give rise to all formed elements
2. hormones and growth factors push cell toward specific pathway of blood cell development
3. committed blood cells can not change
42
The stages of erythropoiesis:
1. myeloid stem cell is transformed into proerythroblast
2. in 15 days proerythroblast develops into basophilic erythroblast
3. then into polychromatic erythroblast
4. then orthochromatic erythroblast
5. then reticulocytes
6. reticulocytes then enter bloodstream, and in 2 days become mature RBC
43
In erythropoiesis, as myeloid stem cell transforms:
1. ribosomes are synthesised
2. hemoglobin is synthesised; iron accumulates
3. nucleus is ejected; reticulocyte is formed (young RBC)
44
After reticulocyte is formed from erythropoiesis:
reticulocyte ribosomes are degraded, then the erythrocyte becomes mature
45
Reticulocyte count indicates:
rate of RBC formation
46
Too few RBCs leads to:
tissue hypoxia
47
Too many RBCs leads to:
increased blood viscosity
48
Balance between RBC production and destruction depends on:
1. hormonal controls
| 2. adequate supplies of iron, amino acids, and B vitamins
49
Erythropoiesis is controlled by the hormone:
erythropoietin (EPO)
50
Erythropoietin has a low number in blood to maintain:
basal rate
51
Depressed production of erythropoietin is caused by:
high RBC or O2 levels
52
EPO is released by ____in response to ____.
kidneys; hypoxia
53
Dialysis patients have how much RBC?
low RBC counts
54
Causes of hypoxia:
1. decreased RBC numbers due to hemorrhage or increased destruction
2. insufficient hemoglobin per RBC (iron deficiency)
3. reduced availability of O2 (high altitudes)
55
What are the effects of EPO?
1. Rapid maturation of committed marrow cells
| 2. Increased circulating reticulocyte count in 1-2 days
56
Athletic abuse of artificial EPO leads to:
higher RBC counts and thicker blood
57
Dietary requirements for erythropoiesis:
1. nutrients
2. iron
3. vitamin B12 and folic acid
58
Nutrients required for erythropoiesis:
1. amino acids
2. lipids
3. carbohydrates
59
Where is iron found?
65% in hemoglobin; the rest is found in the liver, spleen, and bone marrow
60
Free iron ions:
1. are toxic
2. iron ions are stored in cells as ferritin and hemosiderin
3. iron transported in blood is bound to protein transferrin
61
vitamin B12 and folic acid is necessary for:
DNA synthesis for rapidly dividing cells (developing RBCs)
62
Life span of an erythrocyte:
100-120 days
63
Dying erythrocytes circulate to:
the spleen; macrophages engulf dying RBCs in the spleen
64
When erythrocytes die, heme and globin are separated, and what results?
1. Iron is salvaged for reuse
2. Heme is degraded to yellow pigment bilirubin
3. the liver secretes bilirubin in bile into the intestines
4. globin is metabolised into amino acids
65
When the liver secretes bilirubin into the intestines:
1. bilirubin is degraded to the pigment urobilinogen
| 2. urobilinogen leaves the body in feces as stercobilin
66
After globin is metabolised into amino acids:
the amino acids are released into circulation
67
Characteristics of anemia:
1. blood has abnormally low O2-carrying capacity
2. blood O2 levels can not support normal metabolism
3. accompanied by fatigue, pallor, shortness of breath, and chills
68
The three causes of anemia:
1. blood loss
2. low RBC production
3. high RBC destruction
69
Causes of anemia, blood loss:
1. acute hemorrhagic anemia
| 2. chronic hemorrhagic anemia
70
Causes of anemia, low RBC production:
1. iron-deficiency anemia
2. pernicious anemia
3. renal anemia
4. aplastic anemia
71
Causes of anemia, high RBC destruction:
1. hemolytic anemia
2. thalassemias
3. sickle cell anemia
72
Aspects of acute hemorrhagic anemia
1. rapid blood loss (e.g., stab wound)
| 2. treated by blood replacement
73
aspect of chronic hemorrhagic anemia
slight but persistent blood loss due to hemorrhoids or bleeding ulcer
74
Iron deficiency anemia is caused by:
1. hemorrhagic anemia
2. low iron intake
3. impaired absorption
75
RBCs in iron-deficiency anemia are
monocytic, hypochromic
76
Iron-deficiency anemia is treated by
iron supplements
77
Pernicious anemia is what kind of disease?
autoimmune; destroys stomach mucosa
78
Pernicious anemia is caused by lack of:
intrinsic factor needed to absorb B12, which leads to deficiency of vitamin B12
79
In pernicious anemia, RBCs:
can not divide; leads to macrocytes
80
Pernicious anemia is treated by:
B12 injections or nasal gel
81
Pernicious anemia can also be caused by:
low dietary B12 (such as in vegetarians)
82
Renal anemia is caused by a lack of:
EPO
83
Renal anemia often accompanies:
renal disease
84
Renal anemia is treated with:
synthetic EPO
85
In aplastic anemia:
1. Red marrow is destroyed or inhibited by drugs, chemicals, radiation, or viruses
2. all cell lines are affected; leads to clotting or immunity defects
86
Aplastic anemia is treated:
1. short-term: transfusions
| 2. long-term: transplanted stem cells
87
Characteristics of hemolytic anemia:
1. premature RBC lysis
2. genetic basis for abnormal hemoglobin
3. globin is abnormal
88
Hemolytic anemia is caused by:
1. hemoglobin abnormalities
2. incompatible transfusions
3. infections
89
Aspects of thalassemias:
1. typically occur in Mediterranean ancestry
2. one globin chain is absent or faulty
3. RBCs are thin, delicate, and deficient in hemoglobin
90
Sickle-cell anemia arises from:
Hemoglobin S
91
In hemoglobin S:
one amino acid is wrong in a globin beta chain
92
Aspects of sickle-cell anemia:
1. RBCs become crescent-shaped when they unload O2 or when blood O2 is low
2. RBCs rupture easily and block small vessels; leads to poor O2 delivery which results in pain
93
Two copies of the sickle-cell gene lead to:
sickle cell anemia
94
one copy of the sickle-cell gene leads to:
sickle cell trait; disease is milder, leading to better chance to survive malaria
95
Acute crisis of sickle cell anemia is treated with:
transfusions; inhaled nitric oxide
96
To prevent sickling of RBCs, ____ induces fetal hemoglobin (which does not sickle) formation.
hydroxyurea
97
Other ways of preventing sickling of RBCs:
1. Blocking RBC ion channels
2. Stem cell transplants
3. Gene therapy
98
Different polycythemias:
1. polycythemia vera
| 2. secondary polycythemia
99
What are the characteristics of polycythemia vera?
1. bone marrow cancer leads to excess RBCs
| 2. severely increased blood viscosity
100
What are the characteristics of secondary polycythemia?
1. Less O2 available (high altitude) or EPO production increases which leads to higher RBC count
2. blood doping
101
Characteristics of leukocytes:
1. function in defense against disease
2. can leave capillaries via diapedesis
3. move through tissue spaces by ameboid motion and positive chemotaxis
102
A condition in which WBC count is over 11,000/mm^3
leukocytosis
103
Two categories of leukocytes:
1. granulocytes
| 2. agranulocytes
104
What is the characteristic of granulocytes and what are granulocytes divided into?
1. Granulocytes have visible cytoplasmic granules
| 2. Divided into: neutrophils, eosinophils, and basophils
105
Characteristic of agranulocytes:
no visible cytoplasmic granules
106
Agranulocytes are divided into:
1. monocytes
| 2. lymphocytes
107
Life span and size of granulocytes:
1. shorter-lived than RBCs
| 2. larger than RBCs
108
Shape of granulocyte nuclei:
lobed
109
Cytoplasmic granules of granulocytes stain specifically with:
Wright's stain
110
Granulocytes are:
all phagocytic to some degree
111
Neutrophils are also called _________.
polymorphonuclear leukocytes (PMNs or polys)
112
Granules of neutrophils stain ____.
lilac
113
Granules of neutrophils contain:
hydrolytic enzymes or defensins
114
Size of neutrophils:
twice the size of RBCs
115
Granules of eosinophils stain:
red
116
Eosinophil nuclei are ___.
bilobed
117
Characteristics of eosinophil granules:
1. lysosome-like
2. role in allergies and asthma
3. role in modulating immune response
118
Eosinophil granules release:
enzymes to digest parasitic worms
119
Basophil granules contain ____.
histamine
120
inflammatory chemical that acts as a vasodilator to attract WBCs to inflamed sites
histamine
121
Basophils are funtionally similar to ____.
mast cells
122
Characteristics of agranulocytes:
1. Lack visible cytoplasmic granules
| 2. Have spherical or kidney-shaped nuclei
123
Lymphocytes are found in:
mostly lymphoid tissue (e.g. lymph nodes, spleen); few circulate in blood
124
Lymphocytes are crucial to:
immunity
125
The two types of lymphocytes are:
1. T lymphocytes (T cells)
| 2. B lymphocytes (B cells)
126
What do T lymphocytes do?
They act against virus-infected cells and tumour cells.
127
What do B lymphocytes do?
They produce plasma cells, which produce antibodies.
128
Monocyte nuclei stain ____.
dark purple
129
The life cycle of a monocyte:
1. leave circulation
2. enter tissues
3. differentiate into macrophages
130
What are the characteristics of monocytes?
1. actively phagocytic cells
| 2. activate lymphocytes to mount an immune response
131
Monocytes are crucial against:
1. viruses
2. intracellular bacterial parasites
3. chronic infections
132
Leukopoiesis is known as:
the production of WBCs
133
Leukopoiesis is stimulated by 2 types of chemical messengers from ____ and _____.
red bone marrow; mature WBCs
134
The 2 chemical messengers that stimulate leukopoiesis:
1. interleukins
| 2. colony-stimulating factors (CSFs)
135
CSFs are named for:
the WBC type they stimulate
136
All leukocytes originate from _____.
hemocytoblasts
137
Leukopoiesis starts out with two types of stem cells:
1. lymphoid stem cells
| 2. myeloid stem cells
138
In leukopoiesis, lymphoid stem cells give rise to:
lymphocytes
139
In leukopoiesis, myeloid stem cells give rise to:
all others
140
Progression of all granulocytes:
1. myeloblast
2. > promyelocyte
3. > myelocyte
4. > band
5. > mature cell
141
Granulocytes are stored in _____.
bone marrow
142
Amount of WBCs produced relative to RBCs:
3 times more
143
WBCs life span:
shorter; die fighting microbes
144
Characteristics of monocytes (leukopoiesis):
1. live several months
| 2. share common precursor with neutrophils
145
Progression of monocytes during leukopoiesis:
1. Monoblast
2. > promonocyte
3. > monocyte
146
Life span of lymphocytes:
live few hours to decades
147
Progression of lymphocyte during leukopoiesis:
1. Lymphoid stem cell
| 2. > T lymphocyte precursors (travel to thymus); B lymphocyte precursors
148
What are the different leukocyte disorders?
1. leukopenia
| 2. leukemias
149
Characteristic of leukopenia:
abnormally low WBC count--drug induced
150
Leukemias are named according to:
abnormal WBC clone involved
151
Myeloid leukemia involves:
myeloblast descendants
152
Acute leukemia derives from ____.
stem cells
153
Acute leukemia primarily affects ____.
children
154
Chronic leukemia is more prevalent in ____.
elderly
155
During leukemia, cancerous leukocytes fill ____.
red bone marrow
156
During leukemia, overproduction of immature WBCs leads to:
crowding out of erythrocytes, which can cause anemia, and bleeding
157
Over production of WBCs in leukemia produces:
overabundant nonfunctional, immature WBCs
158
Results from leukemia:
1. death from internal hemorrhage
| 2. overwhelming infections
159
Leukemia can be treated by:
1. irradiation
2. antileukemic drugs
3. stem cell transplants
160
Characteristics of infectious mononucleosis:
1. highly contagious viral disease--Epstein-Barr virus (human herpesvirus 4)
2. high number of atypical agranulocytes
3. runs its course with sleep
161
Symptoms of infectious mononucleosis:
1. tired
2. aches
3. chronic sore throat
4. low fever
162
Platelets are fragments of _____.
megakaryocytes
163
Platelets stain:
1. blue in outer region
| 2. purple in granules
164
Granules of platelets contain:
1. serotonin
2. Ca2+
3. enzymes
4. ADP
5. platelet-derived growth factor (PDGF)
165
All of the things that granules of platelets contain, play a part in:
the clotting process
166
What are the overall characteristics of platelets?
1. Form temporary platelet plug that helps seal breaks in blood vessels
2. Circulating platelets are kept inactive and mobile by nitric oxide (NO) and prostacyclin from endothelial cells lining blood vessels
167
Life span of platelets:
age quickly, degenerate in about 10 days
168
Platelet formation is regulated by ____.
thrombopoietin
169
Platelets derive from ____.
megakaryoblasts
170
Progression of platelets:
1. mitosis but no cytokinesis
| 2. > megakaryocyte
171
large cell with multilobed nucleus
megakaryocyte
172
Hemostasis requires:
1. clotting factors
| 2. substances released by platelets and injured tissues
173
What are the three steps of hemostasis?
1. Vascular spasm
2. Platelet plug formation
3. Coagulation (blood clotting)
174
Characteristics of vascular spasm in hemostasis:
1. vasoconstriction of damaged blood vessel
| 2. most effective in smaller blood vessels
175
Vascular spasm is triggered by:
1. direct injury to vascular smooth muscle
2. chemicals released by endothelial cells and platelets
3. pain reflexes
176
Platelet plug formation acts in a ____.
positive feedback cycle
177
During platelet plug formation, damaged endothelium exposes ____.
collagen fibres
178
Exposure of collagen fibres leads to:
platelets sticking via the plasma protein [von Willebrand factor]
179
After the platelets attach to the collagen fibres, they:
1. swell
2. become spiked and sticky
3. release chemical messengers
180
Chemical messengers that platelets release during platelet plug formation are:
1. ADP
2. serotonin
3. thromboxane A2
181
When platelets release ADP, what does it do?
causes more platelets to stick and release their contents
182
When platelets release serotonin and thromoxane A2, what do they do?
enhance vascular spasm and platelet aggregation
183
During coagulation, platelet plug is reinforced with ____.
fibrin threads
184
During coagulation, blood is transformed from ____ to ____.
liquid; gel
185
During coagulation, there is a series of reactions using ____.
clotting factors (procoagulants)
186
What is needed to synthesise 4 of the 13 clotting factors?
Vitamin K
187
The three phases of coagulation are:
1. prothrombin activator is formed in both intrinsic and extrinsic pathways
2. prothrombin is converted to enzyme thrombin
3. thrombin catalyses fibrinogen which leads to fibrin
188
Prothrombin activator is initiated by:
either intrinsic or extrinsic pathway (usually both)
189
What are the aspects of prothrombin activator initiation?
1. triggered by tissue-damaging events
2. involves a series of procoagulants
3. each pathway cascades toward factor X
190
Factor X complexes with ___, ____, and ____ to form _____.
Ca2+; PF3; factor V; prothrombin activator
191
What are the aspects of prothrombin activator initiation by intrinsic pathway?
1. triggered by negatively charged surfaces (activated platelets, collagen, and glass)
2. uses factors present within blood (intrinsic)
192
What are the aspects of prothrombin activator initiation by extrinsic pathway?
1. triggered by exposure to tissue factor (TF) or factor III (an extrinsic factor)
2. bypasses several steps of intrinsic pathway, so it is faster
193
Coagulation phase 2: pathway to thrombin: Prothrombin activator catalyses transformation of ____ to ____.
prothrombin; active enzyme thrombin
194
Coagulation phase 2: pathway to thrombin: Once prothrombin activator is formed:
clot forms in 10-15 seconds
195
Coagulation phase 3: common pathway to the fibrin mesh: Active enzyme thrombin converts ___ to ___.
soluble fibrinogen; fibrin
196
Coagulation phase 3: common pathway to the fibrin mesh: Fibrin strands form _____.
structural basis of clot
197
Coagulation phase 3: common pathway to the fibrin mesh: Fibrin causes plasma to:
become a gel-like trap for formed elements
198
Coagulation phase 3: common pathway to the fibrin mesh: Thrombin (with Ca2+) activates ____.
factor XIII
199
After activation of factor XIII, what does it do?
1. cross-links fibrin
| 2. strengthens and stabilises clot
