Blood Flashcards
1
Q
The blood represents about __% of total body weight
A
The blood represents about 8% of total body weight
2
Q
Average volumes of blood in men and women (cardiac output)
A
5 L in women, 5.5 L in men
3
Q
3 cellular elements in plasma
A
erythrocytes, leukocytes, platelets
4
Q
Erythrocytes (RBCs)
A
important in oxygen and carbon dioxide transport to body tissue
5
Q
Leukocytes (WBCs)
A
immune system’s mobile defence units i.e., antibodies
6
Q
Platelets (thrombocytes)
A
important in hemostasis (blood clotting)
7
Q
% of plasma in blood
A
plasma makes up 55% of whole blood
8
Q
% of blood that is not plasma
A
<1% of whole blood buffy coat- platelets and leukocytes
45% of whole blood- erythrocytes
9
Q
What happens if there is less than 45% of erythrocytes in the whole blood
A
anemia, hemoglobin deficiency
10
Q
Types of leukocytes
A
neutrophils, eosinophils, basophils, monocytes, lymphocytes (B and T)
11
Q
Hematocrit/PCV
A
percentage by volume of red blood cells in your blood- 99% of cells in a centrifuged test tube are composed of RBCs, <1% are WBCs and platelets
12
Q
Plasma is composed of __% water
A
Plasma is composed of 90% water
13
Q
Plasma proteins compose __-__% of plasma’s total weight
A
Plasma proteins compose 6-8% of plasma’s total weight
14
Q
Inorganic and organic substances represent __% of plasma weight
A
Inorganic and organic substances represent 1% of plasma weight
15
Q
3 plasma proteins
A
albumins, globulins, fibrinogens
16
Q
Albumins
A
- most abundant
- contribute to plasma colloid osmotic pressure (important for exchange of material)
- transport many poorly soluble substances in the plasma e.g. bilirubin, penicillin, bile salts etc.
17
Q
Globulins
A
-exists in 3 forms (alpha, beta and gamma)
- these units bind and transport many substances, such as TH, iron and cholesterol in the plasma
- alpha and beta transport many water-insoluble substances
- alpha globulin activates the conversion of angiotensinogen into angiotensin II to regulate salt-water balance in the body (RAAS activated when mild dehydration)
- gamma globulins (immunoglobulins) are another name for antibodies
18
Q
fibrinogens
A
- Involved in clot formation (fibrinogen–>fibrin –> clot)
- produced by liver and circulates in plasma, rupture in blood vessel activates fibrinogen
19
Q
Erythrocyte structure
A
- contain no nucleus, organelles or ribosomes
- biconcave, flat, discs shape
20
Q
Benefits of the erythrocyte struture
A
- it provides a larger SA for oxygen diffusion across the membrane
- the thinness of the cell enables rapid oxygen diffusion
- the flexible membrane allows RBCs to travel through narrow capillaries without rupturing
21
Q
What in the RBC is responsible for its oxygen and carbon dioxide transportation abilities
A
hemoglobin
22
Q
Hemoglobin
A
an iron-rich protein in red blood cells. It gives blood its red colour.
23
Q
two parts of hemoglobin molecules
A
globin portion and heme groups
24
Q
Globin portion
A
a protein composed of 4 highly folded polypeptide chains
25
Heme groups
4 iron-containing non-protein groups, each is bound to one of the polypeptides
26
Primary role of hemoglobin
to carry oxygen
27
___% of oxygen is carried in the blood bound to hemoglobin
98.5% of oxygen is carried in the blood bound to hemoglobin
28
Both carbon dioxide and oxygen bind to hemoglobin but oxygen binds to __/__ and carbon dioxide binds to __ __ of the __ portions of hemoglobin
Both carbon dioxide and oxygen bind to hemoglobin but oxygen binds to heme/iron and carbon dioxide binds to amino acids of the globin portions of hemoglobin
29
Hemoglobin also binds with..
carbon dioxide, the acidic H+ ion, CO, NO
30
Hemoglobin helps transport carbon dioxide from __ to the __
Hemoglobin helps transport carbon dioxide from tissue to the lungs
31
CO occupies __ binding sites on hemoglobin, causing CO poisoning
CO occupies oxygen binding sites on hemoglobin, causing CO poisoning
32
In the lungs, __ binds to hemoglobin molecule. In tissue, __ acts as, vasodilator to arterioles and help stabilize blood pressure by vasodilation and vasoconstriction
In the lungs, NO binds to hemoglobin molecule. In tissue, NO acts as, vasodilator to arterioles and help stabilize blood pressure by vasodilation and vasoconstriction
33
Adult blood contains about __-__ __ RBC passing through it at any time
Adult blood contains about 25-30 trillion RBC passing through it at any time
34
immature RBCs have a __ and __ __, their energy supplies/proteins produced last for __ days, and then they mature in the __ ___ where they will then have no nucleus
immature RBCs have a nucleus and cell organelles, their energy supplies/proteins produced last for 120 days, and then they mature in the bone marrow where they will then have no nucleus
35
RBCs last about __ __ in circulation
RBCs last about 120 days in circulation
36
the ___ removes most of the old erythrocytes from circulation
the spleen removes most of the old erythrocytes from circulation
37
erythrocytes must be replaced at a rate of __-__ __ cells/second
erythrocytes must be replaced at a rate of 2-3 million cells/second
38
pluripotent stem cells in __ __ __ differentiate into different types of blood cells
pluripotent stem cells in red bone marrow differentiate into different types of blood cells
39
Erythropoietin (EPO)
a hormone secreted by the kidneys that stimulate RBC production
40
Erythropoiesis
body's process of making red blood cells (erythrocytes)
41
Source of erythropoietin
kidney
42
Role of erythropoietin in erythropoiesis
1. The kidneys detect reduced oxygen-carrying capacity of the blood
2. when less oxygen is delivered to the kidneys, they secrete the hormone erythropoietin into the blood
3. erythropoietin stimulates erythropoiesis (erythrocyte production) by the bone marrow
4. the additional circulating erythrocytes increase the oxygen-carrying capacity of the blood
5. the increased oxygen-carrying capacity relieves the initial stimulus that triggered erythropoietin secretion
43
Anemia
refers to a below-than-normal oxygen-carrying capacity of the blood, characterized by a low hematocrit
44
Causes of anemia
decreased rate of erythropoiesis (not able to produce erythropoietin), excessive loss of RBC, deficiency in the hemoglobin content of RBC
45
Types of anemia
nutritional, pernicious and hemolytic
46
Nutritional anemia
- caused by iron deficient diet; iron is essential for the production of hemoglobin and erythropoiesis
- RBCs are produced but contain less hemoglobin than normal since they can not transport oxygen in a greater quantity
47
Causes of pernicious anemia
- failure to absorb vitamin B12 for the digestive system (small intestine)
- deficiency in intrinsic factor (secreted by stomach lining)
- B12 is important for normal RBC production and only absorbed from the intestine when bind to intrinsic factor
- leads to the impairment of RBC production and maturation
48
Causes of hemolytic anemia/sickle-cell anemia
- rupture of an excessive number of circulating RBCs (haemolysis)
- defects in RBC or rupture induced by external factors (malaria parasites)
- various hereditary abnormalities of erythrocytes
- the defective type of hemoglobin polymerizes
- deformed RBCs clump together, compromising blood flow through a small blood vessel and leading to tissue damage
- the rate of RBC rupture exceeds the rate of erythropoiesis
49
Polycythemia
characterized by too many circulating RBCs and elevated hematocrit
50
2 general types of polycythemia
primary and secondary polycythemia
51
Primary polycythemia
- caused by the tumorlike condition of bone marrow
-erythropoiesis proceeds at uncontrolled rate
52
Secondary polycythemia
- erythropoietin-induced adaptive mechanism improves blood's oxygen-carrying capacity in response to prolonged reduced oxygen delivery to the tissues
- occurs normally in people living at high altitudes
-sometimes called relative polycythemia
53
Leukocytes
- white blood cells
- mobile units of the body's immune defence system
- colorless- lack hemoglobin
- larger than erythrocytes
54
the 5 different types of circulating leukocytes
1. neutrophils
2. monocytes
3. basophils
4. eosinophils
5. lymphocytes
55
Red bone marrow is where __ ___ cells, ___ and ___ ___ cells are created
Red bone marrow is where red blood cells, platelets and white blood cells are created
56
Where are granulocytes and monocytes produced? Where are lymphocytes produced?
Granulocytes and monocytes are produced only in bone marrow. Most new lymphocytes are produced in lymphocytes already in lymphoid tissues such as lymph nodes and tonsils
57
functions of leukocytes
- defends against invading pathogens
- identifies and destroys cancer cells that arise in the body
-functions as a "cleanup crew" that removes worn-out cells and tissue debris
58
Neutrophils
- phagocytic specialists
- release web of extracellular fibers called neutrophil extracellular traps (NETs) that contain bacteria-killing chemicals
- can also destroy bacteria by phagocytosis
- functions: first defenders on the scene of bacterial invasion, very important in inflammatory responses, scavenge to clean up debris
59
An increase in circulating eosinophils is associated with...
- allergic conditions such as asthma and hay fever
- internal parasite infestations, such as worms
60
Basophils
- least numerous and most poorly understood of leukocytes
-quite similar structurally and functionally to mast cells
61
What are 2 things basophils synthesizes and stores
1. histamine: release is important in allergic reactions
2. heparin: speeds up the removal of fat particles from blood after a fatty meal, can also prevent clotting of blood samples drawn for chemical analysis, used extensively as an anticoagulant drug
62
Monocytes
- emerge from bone marrow while still immature and circulate for a day or two before settling down in various tissues in the body
- mature and enlarge in resident tissue known as macrophages
63
Lymphocytes
provide immune defence against targets for which they are specifically programmed
64
2 types of lymphocytes
B and T lymphocytes
65
B lymphocytes
- humoral immunity
- produce antibodies
- responsible for antibody-mediated immunity
66
T lymphocytes
- cell-mediated immunity
- do not produce antibodies
- directly destroy specific target cells by releasing chemicals that punch holes in the victim cell
- target cells include body cells invaded by viruses and cancer cells
67
Platelets
- cell fragments shed from megakaryocytes
- lack nuclei
- have organelles and cytosolic enzymes for generating energy and synthesizing secretory products
- high concentrations of actin and myosin
- remain functional for an average of 10 days
- removed from circulation by tissue macrophages
- blood contains 250 million/ml platelets
68
Thrombopoietin
hormone produced by liver increases the number of megakaryocytes and therefore increases platelet production
69
Microcirculatory vessels
venules, capillaries, arterioles
70
Haemostasis
prevents blood loss from a broken blood vessel
71
Causes of bleeding
break in blood vessel, the difference in pressure inside and outside of the blood vessel
72
3 major steps of haemostasis
1. vascular spasm
2. formation of a platelet plug
3. blood coagulation (clotting)
73
Vascular spasm
reduces (does not stop fully) blood flow through a damaged vessel. When there is an injury, vasoconstriction occurs. This will bring the endothelial cells closer together to decrease the rupture site
74
Formation of a platelet plug
1)platelets adhere to and are activated by exposed collagen at the site of vessel injury
2)activated platelets release ADP and thromboxane A2
3)these chemical messengers work together to activate other platelets passing by- makes surface sticky
4) newly activated platelets aggregate onto growing platelet plug and release even more platelet-attracting chemicals
5) normal (uninjured) endothelium releases prostacyclin and nitric oxide, which inhibit platelet aggregation, so platelet plug is confined to site of injury
75
Blood coagulation (clotting)
transformation of blood from a liquid into a solid gel
76
__-__ ___ within the aggregated platelets contract to compact and strengthen the loose plug
Actin-myosin complexes within the aggregated platelets contract to compact and strengthen the loose plug
77
Clot formation process
1) fibrinogen released from the liver
2) converted when there is a rupture by enzyme thrombin (at injured site) to fibrin
3) fibrin will adhere to the damaged vessel surface and attract other blood cellular elements (aggregated platelets) to form clot
4) factor XIII (fibrin-stabilizing factor) (plasma) will cause cross-linkage and strengthen fibrin strands
78
Platelet plug purpose
The plug provides a temporary blockage of the break in the vasculature. As such, platelet plug formation occurs after vasoconstriction of the blood vessels but before the creation of the fibrin mesh clot, which is the more permanent solution to the injury
79
What happens if a blood clot gets loose
an embolism or thrombus
80
Role of thrombin in clot formation
1. converts fibrinogen into fibrin
2. activates factor XIII to stabilize fibrin mesh
3. acts in a positive feedback fashion to facilitate its own formation
4. enhances platelet aggregation for the clotting process
81
Factor X
converts prothrombin into thrombin
82
Intrinsic pathway
- involves 7 separate steps
- set off when factor XII (hageman factor) is activated by coming into contact with exposed collagen in an injured vessel or foreign surface such as a glass test tube
83
Extrinsic pathway
- requires only 4 steps
- requires contact with tissue factors external to the blood
- tissue thromboplastin released from traumatized tissue directly activates factor X
84
How many steps is the intrinsic pathway
7
85
How many steps is the extrinsic pathway
4
86
The ___ pathway is activated by factors in the blood, while ___ is activated by tissue factor
The intrinsic pathway is activated by factors in the blood, while extrinsic is activated by tissue factor
87
Clot retraction
contraction of platelets shrinks fibrin mesh, squeezing fluid from the clot
88
Clot dissolution
enzyme plasmin dissolves the clot, plasmin formed from plasminogen
89
Vessel repair
- aggregated platelets secrete a chemical that promotes the invasion of fibroblasts from surrounding connective tissue
- fibroblast forms a scar at the vessel defect
90
Thrombus
- abnormal intravascular clot attached to a vessel wall
- can eventually completely occlude the vessel
91
Emboli
- freely floating clots
- can suddenly block blood flow
92
factors that cause thromboembolism
- roughened vessel surfaces associated with atherosclerosis
- imbalances in the clotting-anticlotting systems
- slow-moving blood
- occasionally release of tissue thromboplastin into the blood from large amounts of traumatized tissue
93
Hemophilia
excessive bleeding caused by a deficiency of one of the factors in the clotting cascade (inability to produce factor VIII)
94
About how many litres of blood are in the human body?
5L
95
Which of the following is NOT a function of plasma proteins?
a. plasma proteins are responsible for the blood colloid osmotic pressure
b. plasma proteins provide a source of readily available amino acids to be utilized by the tissue cells for the synthesis of new tissue proteins
c. gamma globulins important in the body's defence mechanism are one of the constituents that stay in the plasma
d. plasma proteins play a role in buffering changes in pH in the body fluids
B
96
The buffy coat, which represents <1% of the whole blood, comprises...
leukocytes and platelets
97
Why is it important that bi-concavity of the erythrocyte on the cell decreases its flexibility?
it increases the rate of gas exchange across the membrane
98
Which plasma globulins are the antibodies?
gamma
99
If the hematocrit is 40, then the volume occupied by which of the following?
a. red blood cells is 60 percent of the total blood volume
b. white blood cells is 40 percent of the total blood volume
c. red blood cells is 40 percent of the total blood volume
d. plasma and other cellular elements is 40 percent of the total blood volume
C- RBC is 40 percent of the total blood volume
100
Which of the following is correct for erythrocytes?
a. they are large cells
b. they participate in the clotting of blood
c. they defend the body against foreign substances
d. they possess binding sites for oxygen and carbon dioxide
D
101
Which statement is true of hemoglobin?
a. is found in the nuclei of RBCs
b. contains carbonic anhydrase
c. can combine with oxygen, carbon dioxide, hydrogen, nitric oxide and carbon monoxide
d. can combine only with oxygen molecules
C
102
Which of the following concerning erythropoiesis is correct?
a. it is accomplished in the bone marrow upon stimulation of erythropoietin
b. it is accomplished in the kidneys in response to reduced oxygen delivery to the kidneys
c. it refers to increased RBC count
d. it refers to excessive RBC destruction
A
103
Which of the following condition (s) would not result in increased rates of erythropoiesis?
a. high altitudes
b. increased physical activity
c. loss of blood
d. greater blood flow to the kidney
D
104
Which of the following types of anemia is caused by a genetic abnormality?
a. pernicious
b. haemorrhagic
c. sickle-cell
d. megaloblastic
C
105
Which of the following is NOT a possible cause of anemia?
a. dietary deficiency of folic acid
b. deficiency of intrinsic factor
c. malaria
d. living at high altitude
D
106
What form of polycythemia occurs when an individual lives in a high-altitude environment?
secondary
107
Which of the following leukocytes contains histamine in its granules?
a. neutrophils
b. eosinophils
c. basophils
d. lymphocytes
C
108
Which of the following leukocytes is implicated in certain allergic reactions and attacks internal parasites such as worms?
a. neutrophils
b. eosinophils
c. basophils
d. lymphocytes
B
109
The tissue phagocytes, macrophages are derived from which white blood cell?
a. neutrophils
b. eosinophils
c. lymphocytes
d. monocytes
D
110
Which statement concerning platelets is incorrect?
a. platelets are produced in the bone marrow
b. platelets form the meshwork of a blood clot upon which the other cellular elements become entrapped
c. platelets form a plug when they adhere to the exposed collagen of a damaged vessel
d. aggregated platelets release serotonin, epinephrine, and thromboxane A2
C
111
What is the platelet count per cubic millimetre that is within the normal range?
a. 100,000
b. 130,000
c. 250,000
d. 600,000
C
112
Which step is not involved in haemostasis?
a. vascular spasms
b. platelet aggregation
c. coagulation
d. thrombopoiesis
D
113
Which chemical signal makes platelets sticky upon aggregation?
a. ADP
b. ATP
c. prostacyclin
d. thromboxane
A
114
Which of the following signals the platelet aggregation to be reinforced?
a. ADP
b. fibrinogen
c. thromboxane
d. prostacyclin
C
115
Which blood cellular elements lack nuclei?
a. platelets
b. erythrocytes
c. leukocytes
d. platelets and erythrocytes
D
116
What does exposed collagen in a damaged vessel do?
a. it activates factor XII to initiate blood clotting
b. it initiates platelet aggregation
c. it secrets ADP, which causes platelets to become sticky
d. it activates factor XII to initiate blood clotting and initiates platelet aggregation
D
117
What are platelets normally attracted to?
a. a collection of WBCs
b. a disrupted surface of a blood vessel
c. a smooth surface
d. a source of ATP production
B
118
Which of the chemical signals is released by healthy endothelial tissue in order to prevent the overgrowth of platelet plugs?
a. ATP
b. fibrinogen
c. prostacyclin
d. thromboxane
C
119
Which statement concerning the extrinsic clotting pathway is correct?
a. it is set off by factor XII
b. it clots blood in tissues
c. it has more steps than the intrinsic pathway
d. it is set off when Hageman factor comes into contact with collagen in an injured vessel
B
120
Which of the following is the correct sequence of events leading to clot formation?
a. prothrombin- thrombin-fibrin-fibrinogen
b. fibrin-prothrombin- fibrinogen- thrombin
c. prothrombin- thrombin- fibrinogen- fibrin
d. fibrin-thrombin-prothrombin- fibrinogen
C
121
Platelets trapped within the fibrous meshwork of the clot ____
retract the clot
122
The percentage of whole blood occupied by erythrocytes, known as the ___, is normally ___ (greater than, less than) the plasma volume
The percentage of whole blood occupied by erythrocytes, known as the hematocrit, is normally less than the plasma volume
123
The 3 types of cellular elements in the blood are ___, ___ and ____
The 3 types of cellular elements in the blood are leukocytes, erythrocytes and platelets
124
Heme in hemoglobin contains four ___- containing groups
Heme in hemoglobin contains four iron- containing groups
125
Most of the old erythrocytes are removed from the circulation as they rupture through the narrow capillaries of the ___
Most of the old erythrocytes are removed from the circulation as they rupture through the narrow capillaries of the spleen
126
The hormone erythropoietin is produced by the ___
kidney
127
RBC production by the ____ is stimulated by the hormone ___, which is secreted from the kidney into the blood in response to ____ ____
RBC production by the bone marrow is stimulated by the hormone erythropoietin, which is secreted from the kidney into the blood in response to low oxygen
128
the 3 major steps in hemostasis are ___ ___, ___ ___ and ___ ___
the 3 major steps in hemostasis are vascular spasm, platelet plug and blood clot
129
The precursor for plasmin is ___
plasminogen
130
___ prevents platelets from aggregation
prostacyclin
131
the most abundant type of granulocyte
neutrophils
132
become tissue macrophages
monocytes
133
produce antibodies
lymphocytes
134
the first phagocytes to arrive at site of bacterial invasion
neutrophils
135
Release histamine and heparin
basophils
136
destroy parasitic worms
eosinophils
137
participate in cell-mediated immune responses
lymphocytes
138
the most abundant type of agranulocyte
lymphocytes
139
similar to mast cells
monocytes
140
Second step in hemostasis
formation of a platelet plug
141
released from injured tissues, activates extrinsic clotting pathway
thromboplastin
142
Converts fibrinogen to fibrin
thrombin
143
A plasma protein activated by factor X
prothrombin
144
Forms the meshwork of the clot
Fibrin
145
Third step in haemostasis
blood coagulation
146
When platelets come into contact with this substance in an injured vessel wall, it causes them to adhere and aggregate
Collagen
147
Substance released by the platelet plug that causes more platelets to aggregate
thromboxane A2
148
When activated, this substance digests the fibrin threads, causing dissolution of the clot
plasminogen
149
First step in hemostasis
Vascular spasm
