Physiology Exam 5 - Blood Physiology Flashcards
(92 cards)
1
Q
What is blood composed of?
A
formed elements suspended in a liquid called plasma
2
Q
How many liters of blood do adults have?
A
5-6 L
3
Q
What is plasma?
A
the matrix of blood; clear, light yellow fluid
4
Q
What are formed elements?
A
cells and cell fragments:
- erythrocytes (no nucleus or organelles)
- white blood cells (cell + nucleus + organelles)
- platelets (parts of cells)
5
Q
What does a centrifuge do to blood?
A
divides it into plasma and formed elements
6
Q
What is the buffy coat?
A
layer of leukocytes and platelets between plasma and erythrocytes
7
Q
What is the hematocrit?
A
volume of red blood cells
8
Q
What is plasma composed of?
A
inorganic and organic substances dissolved in water (majority - 92%)
- electrolytes, nutrients, wastes, gases (1%)
- hormones
- plasma proteins (7%)
9
Q
What are the plasma proteins?
A
- albumins - 58%
- globulins - 37%
- fibrinogen - 4%
- regulatory proteins - <1%
10
Q
What is serum?
A
plasma minus fibrinogen and other clotting-related proteins
11
Q
What is hematopoiesis?
A
the production of all the formed elements of the blood
12
Q
What is the daily adult production of the different formed elements?
A
- 400 billion platelets
- 100 to 200 billion RBCs
- 10 billion WBCs
13
Q
What is the multipotential hematopoietic stem cell?
A
a cell that can differentiate into many types of cells; it exhibits self-renewal
14
Q
What does the yolk sac do?
A
produces stem cells for the first blood cells
15
Q
What harbors stem cells during fetal development?
A
liver, spleen, and thymus
16
Q
What harbors stem cells during fetal development and in adulthood?
A
bone marrow
17
Q
What organ never has hematopoietic stem cells?
A
the brain - the blood brain barrier doesn’t allow the big cells to pass
18
Q
What is the main function of RBCs?
A
gas transport - carrying O2 from lungs to tissues and CO2 from tissues to lungs
19
Q
What is the shape of a RBC?
A
discoid cell with biconcave shape
20
Q
What do RBCs lack?
A
mitochondria (make energy anaerobically) and nucleus and DNA (cannot replicate)
21
Q
How long is the RBC lifespan?
A
120 days
22
Q
Where are RBCs synthesized?
A
red bone marrow
23
Q
What is the process of RBC synthesis called?
A
erythropoiesis
24
Q
What initiates erythropoiesis?
A
erythropoietin - produced by kidneys in adult and liver in fetal
25
What is the hemoglobin composition of an erythrocyte?
- 33% of the cytoplasm is hemoglobin
- 280 million hemoglobin molecules are in one erythrocyte
26
What is the structure of hemoglobin?
quaternary protein with 2 beta and 2 alpha subunits
27
What are the four polypeptide subunits of hemoglobin referred to as?
globins - they bind small amounts of CO2
28
What binds oxygen to hemoglobin and where?
Ferrous ion (Fe) at the center of hemoglobin
29
How long does it take to develop erythrocytes?
3 to 5 days
30
What are the steps of erythrocyte formation?
- reduction in cell size
- increase in cell number
- synthesis of hemoglobin
- loss of nucleus
31
What is hypoxemia?
low level of oxygen - it increases erythropoiesis through a negative feedback loop
32
What is hemolysis and where does is occur?
the destruction of red blood cells occurring in the spleen and liver
33
What do macrophages in the spleen do?
separate heme from globin (denature the protein)
34
What is the heme pigment converted into during RBC death and disposal?
biliverdin (green) and bilirubin (yellow)
35
What does the liver do to bilirubin?
removes it and secretes it into bile (gallbladder) and then to small intestine (urobilinogen - brown feces)
36
What is the color of arterial blood?
bright red - a lot of O2
37
What is the color of venous blood?
dark crimson - a lot of CO2
38
What is polycythemia?
a high concentration of RBCs
39
What is anemia?
a low concentration of RBCs
40
How does polycythemia affect plasma/hematocrit ratio?
elevated hematocrit
41
How does anemia affect plasma/hematocrit ratio?
depressed hematocrit
42
What are the three causes of anemia?
- hemorrhagic anemia from bleeding
- hemolytic anemia from RBC destruction
- inadequate erythropoiesis or hemoglobin synthesis
43
What is pernicious anemia?
autoimmune attack of stomach tissue (low intrinsic factor) leads to inadequate vitamin B12 absorption
44
What is hypoplastic anemia?
slowing of erythropoiesis
45
What is aplastic anemia?
complete cessation of erythropoiesis
46
What is primary polycythemia?
cancer of erythropoietic cell line causing RBC counts as high as 11 million RBCs per microliter (80% hematocrit)
47
What is secondary polycythemia?
dehydration, emphysema, high altitude, physical conditioning causing RBC count up to 8 million RBCs per microliter
48
What are the dangers of polycythemia?
- increased blood volume, pressure, and viscosity
- can lead to embolism, stroke, or heart failure
49
In what population is Sickle-Cell disease common?
people of African descent
50
What occurs in someone with Sickle-Cell disease?
the recessive allele modifies the structure of Hb (makes HbS)
- HbS does not bind O2 well
- RBCs become rigid, sticky, pointed at the ends
- they clump together and block small blood vessels
51
What are heterozygotes for the Sickle-Cell allele resistant to?
malaria
52
What is hypoproteinemia?
a deficiency of plasma proteins
53
What causes hypoproteinemia?
- extreme starvation
- liver or kidney disease
- severe burns
54
What is Kwashiorkor?
children with a severe protein deficiency who are fed on cereals once weaned from breastmilk
55
What does Kwashiorkor cause?
- thin arms and legs
- swollen abdomen
56
Who discovered the blood types and when?
Karl Landsteiner in 1900
57
What are blood types based on?
interactions between antigens and antibodies
58
What are antigens?
molecules on cell membrane surface that activate an immune response
59
What are characteristics of antigens?
- they are genetically unique to the individual
- they can distinguish themselves from foreign matter
- foreign antigens generate an immune response
60
What are agglutinogens?
antigens on the surface of RBCs that are the basis of blood typing
61
What are antibodies?
proteins (gamma globulins) secreted by plasma cells
62
What is the function of antibodies?
- provide an immune response to foreign matter
- bind to antigens and mark them for destruction
- forms antigen-antibody complexes
63
What type of antigens does a blood type A person have?
A antigens
64
What type of antigens does a blood type B person have?
B antigens
65
What type of antigens does a blood type AB person have?
A and B antigen
66
What type of antigens does a blood type O person have?
neither antigen A or B
67
What are agglutinins?
antibodies that make RBCs clump together
68
What is agglutination?
the clumping of RBCs caused by agglutinins (antibodies) binding to agglutinogens (antigens)
69
What can agglutinins in plasma do for transfusion?
causes transfusion mismatch
70
When were Rh (C, D, E) agglutinogens discovered?
1940 in rhesus monkey
71
What is Rh D?
Rh factor - the most reactive (immunogenic); most expressed on RBCs
72
What is the blood type if there are D antigens on RBC's?
Rh +
73
What is the blood type if there are no D antigens on RBC's?
Rh -
74
How many total blood types are there?
8
75
What are transfusion reactions?
medical complications that arise after transfusion of whole blood or some of its components
76
What are the types of transfusion reactions?
- acute (immediate symptoms)
- delayed (days to weeks later)
77
What causes transfusion reactions?
- donor's RBCs agglutinate as they enter the recipient
- agglutinated RBC's block small blood vessels and capillaries
- agglutination causes hemolysis (opens up hemoglobin in RBC and breaks up)
- high amounts of hemoglobin can block kidney tubules (acute renal failure)
78
What are characteristics of platelets?
- 2 to 4 micrometers in diameter
- contain "granules"
- complex internal structure
- open canalicular system (OCS - important for delivery of coagulation factors/molecules)
- amoeboid movement and phagocytosis
- normal count - 130,000 - 400,000 platelets per microliter
79
What is the function of platelets?
- secrete vasoconstrictors that help reduce blood loss
- stick together to form platelet plugs to seal small breaks
- secrete procoagulants (clotting factors) to promote clotting
- initiate formation of clot-dissolving enzyme
80
What is hemostasis?
the stoppage of bleeding
81
What are the three steps of hemostasis?
1. vascular spasm
2. platelet plug formation
3. blood clotting (coagulation)
82
Which step of hemostasis is the fastest?
vascular spasm
83
Which step of hemostasis is the longest and most effective in stopping bleeding?
blood clotting (coagulation)
84
What happens during vascular spasm?
rapid constriction of a broken vessel
mechanisms:
- some nociceptors directly trigger constriction
- smooth muscle injury
- platelets release serotonin (vacoconstrictor)
85
What happens during platelet plug formation I?
- absence of prostacyclin (causes vasodilation) in broken endothelium
- broken vessel exposes collagen
- platelet pseudopods stick to collagen (due to von Willebrand factor)
- pseudopods contract, draw together a platelet plug
86
What happens during platelet plug formation 2?
platelets degranulate (release contents)
- serotonin (vasoconstrictor)
- Adenosine diphosphate (attracts more platelets)
- Thromboxane A2 (platelet aggregation, degranulation, and vasoconstriction)
this positive feedback cycle occurs until the break in vessel is sealed
87
What happens during coagulation?
fibrinogen converts into fibrin threads
procoagulants:
- present in plasma
- produced by the liver
- reaction cascade
88
What does vitamin K do?
it is needed for some coagulation factors to be activated: 2, 7, 9, 10
89
What is platelet-derived growth factor (PDGF)?
platelets and endothelial cells that are a mitotic stimulant for fibroblasts and smooth muscle
90
What is fibrinolysis?
the dissolution of a clot
91
What is hemophilia?
a genetic disorder caused by a deficiency of a gene for a specific coagulation factor
92
What is von Willebrand's disease?
- reduced levels of vWf
- decreased platelet plug formation
