Blood Flashcards
(92 cards)
1
Q
Functions of the blood?
A
- Oxygen from lungs to organs/cells
- Carbon dioxide from cells to lungs
- Nutrients from digestive system and storage
- Wastes to liver and kidneys (metabolic reactions)
- Hormones
- Regulates body temperature (transports heat out of skin)
- Immunity (WBC fight off infections)
- Clotting (platelets)
- Stabilizes water balance
- Stabilizes pH (buffer for acids and bases)
2
Q
What are the formed elements?
A
RBC, WBC, and platelets
3
Q
What is an Erythocyte?
A
Red blood cell
4
Q
What is a Leukocyte?
A
White blood cell
5
Q
How many liters of blood do adults have?
A
4-6L
6
Q
What is Plasma?
A
A clear extracellular fluid (55% of blood)
7
Q
What is the mean erythrocyte count?
A
4.2-6.2 million/ml
8
Q
What is the mean leukocyte count?
A
5,000-10,000/ml
9
Q
What is the mean platelet count?
A
130,000-400,000/ml
10
Q
What is a Granulocyte?
A
- Little “grains of sand” in cells.
- Neutrophils, Eosinophils, Basophils
11
Q
What is an Agranulocyte?
A
- No cytoplasmic granules
- Lymphocytes and Monocytes (Macrophages)
12
Q
What is Hematocrit?
A
- the % of total volume that is cells.
- Centrifuging blood forces formed elements to separate from plasma
13
Q
How much total volume of hematocrit are in erythrocytes?
A
- 37%-52% total volume
- Erythrocytes are heaviest and settle first
14
Q
How much hematocrit are in Leukocytes and platelets?
A
- 1% total volume
- Buffy coat
15
Q
How much hematocrit is in plasma?
A
47%-63%
16
Q
What is viscosity?
A
- the resistance to flow (thickness/stickyness)
- Blood is 4.5-5.5 times more viscous than water
- Plasma alone is 2 times more viscous than water.
- Too many or too few red blood cells changes the viscosity of blood and puts a strain on the heart
17
Q
What is osmolarity?
A
- total molar concentration of dissolved particles in 1L of solution due to transfer of nutrients and wastes between the blood and tissue fluids
- more solute= more osmolarity
- less solute= less osmolarity
- it too high: bloodstream absorbs too much fluid from the tissues, thus causing hypertension (high BP)
- if too low: bloodstream transfers too much fluid to tissues, resulting in edema and hypotension (low BP)
18
Q
What does Plasma contain?
A
- 92% water
- proteins, enzymes, nutrients, wastes, hormones, lipids, trace elements, gases
- serum: plasma minus the clotting proteins
19
Q
True or False: Proteins are the most abundant solute in plasma?
A
True: they are used for clotting, defense, and transport
20
Q
What are Albumins?
A
- most abundant plasma protein
- produced by the liver
- contribute to viscosity and osmolarity and influences blood pressure, flow, and fluid balance.
21
Q
What is Fibrinogen?
A
clotting protein
22
Q
What are Globulins?
A
immune system defenses
23
Q
What is Hemopoiesis?
A
- Blood cell production: produce formed elements
24
Q
What is red bone marrow?
A
- produces RBCs, WBCs, and platelets
- committed cells are destined to continue down a specific cell line
25
What are Hemopoietic stem cells?
- adult stem cells that multiply continually and are pluripotent (capable of differentiating into multiple cell lines)
- differentiate into colony-forming units (CFUs) that give rise to the different formed elements.
26
What is Erythropoietin?
- hormone produced by the liver
- no nucleus or organelles (does not undergo mitosis)
- lives for ~120 days
27
What is Erythropoiesis?
- the production of erythrocytes begins with a hemopoietic stem cell in the red bone marrow
- Erythropoiesis produces 2.5 million RBCs/second
- Development takes 3-5 days
28
What are the steps of Erythropoiesis?
1. Hemopoietic stem cell
2. Colony-forming unit (Erythrocyte CFU is present)
3. Precursor cells (Erythroblasts and Reticulocytes are present)
4. Mature cell (Erythrocyte is formed)
29
What are nutritional needs for Eythropoiesis?
- iron, B12 and folic acid, Vitamin C and copper
30
Why is iron a nutritional need to erythropoiesis?
- it is lost daily through urine, feces, and bleeding
- low absorption rate requires consumption of 5-20mg/day
31
Why is B12 and folic acid a nutritional need for Erythropoiesis?
- for DNA synthesis and rapid cell division
32
Why is Vitamin C and copper a nutritional need for Erythropoiesis?
- Cofactors for enzymes synthesizing RBCs
33
Erythrocytes
- disc-shaped, thick rim, sunken center
- outer surface of the plasma membrane has glycoproteins and glycolipids
- inner surface of plasma membrane has two types of proteins, actin and spectin (resilience and durability)
- only cells of body that carry on anaerobic fermentation indefinitely, so they don't use the O2n they transport
34
Major functions of Erythrocytes
- gas transport!
- increased surface area/volume ratio due to loss of organelles during maturation
- 33% of cytoplasm is hemoglobin
-
35
What is carbonic anhydrase?
- in cytoplasm
- produces carbonic acid from CO2 and water
- important role in CO2 gas transport and pH balance
36
How many protein chains does hemoglobin consists of?
- 4 protein chains called globins
- 2 alpha and 2 beta
- each protein chain is conjugated with a heme group that binds oxygen to ferrous ion
37
How many oxygen can a hemoglobin molecule carry?
4 O2
38
True of False: RBC count and hemoglobin concentration indicate the amount of oxygen the blood can carry.
True
39
Why are the values of Erythrocytes and Hemoglobin lower in women?
- lower hematocrit
- androgens stimulate RBC production
- women have periodic menstrual losses
- counts are inversely proportional to body fat
40
True or False: Women clot faster than men
False: Men's blood clots faster because they have fewer skin blood vessels.
41
What feedback control does Erythrocyte Homeostasis have?
Classical negative feedback control
42
What is hypoxemia?
- too few RBCs to supply body tissues with required amounts of O2= O2 deficiency
- kidneys release erythropoietin: stimulate red bone marrow hemopoetic stem cells to differentiate into erythrocyte colony-forming units
43
Negative feedback in erythrocyte homeostasis
- as RBC counts rise, secretion of erythropoietin decreases
44
What are the causes of hypoxemia?
- loss of blood (bleeding, donating blood)
- high altitudes: less O2 availability causes hypoxemia in the average individual with 5 million RBCs/ml
- sedentary person starts exercise program, thus requiring more O2
45
Erythrocyte death and disposal
- RBCs live for ~120 days: membrane becomes fragile, deterioration of actin and spectrin. spleen is known as the erythrocyte graveyard
- macrophages in spleen: digest membrane bits, separate heme from globin, hydrolyze globin--> amino acids, remove iron from heme, convert heme to bilirubin
46
What is polycythemia?
- an excess of RBCs
- primary polycythemia: due to cancer of erythropoietic cell line (RBC count as high as 11 million; hematocrit of 80%
- secondary polycythemia: RBC count up to 8 million
47
More erythrocyte disorders...
- dehydration: more RBCs due to less plasma
- high altitude: edtended stay at high altitude. RBC rises to 7-8 million
- physical conditioning: endurance trained athletes (higher RBC) have ~6.5 million RBCs due to higher oxygen requirements
emphysema: less lung tissue. RBCs can't correct for this, but erythropoietin is still released
48
What are the dangers of polycythemia?
- increased blood volume, pressure and viscosity can lead to poor circulation, heart strain and clogged capillaries (which can lead to embolism (traveling blood clots), stroke, or heart failure)
49
What is iron-deficiency anemia?
- dietary iron deficiency= Hb
- not enough RBC
50
What is Pernicious anemia?
- inadequate vitamin B12
- poor nutrition
- lack of intrinsic factor (facilitates B12 absorption)
51
What is Hypoplastic anemia?
- decline in RBC production
- kidney failure: insufficient erythropoietin hormone production
- destruction of myeloid tissue
- radiation, viral infection, poisoning, autoimmune disease
52
What is aplastic anemia?
- complete cessation of RBC production
- cause is unknown
53
What is Hemorhagic anemia?
- loss of blood
54
What is hemolytic anemia?
- RBC destruction
- motther-fetus mismatch, mushroom toxins, snake or spider venom, drug reactions, malaria (parasites destroy RBCs)
55
What are the consequences of anemia?
- tissues are deprived of O2 (hypoxia/hypoxemia)
- shortness of breath
- lethargy (lack of energy)
- tissue necrosis (tissue destruction)
- reduced blood viscosity: less blood flow resistance
-heart beats faster
- blood pressure drops
- heart failure
56
What is sickle-cell disease?
- hereditary hemoglobin defects
- caused by a recessive allele that modifies that structure of the hemoglobin molecule (HbS- hemoglobin S "sickle")
- Differs only on the sixth amino acids of the beta chain
- HbS does not bing oxygen well
- RBCs become rigid, sticky, pointed
- Clump together and block small blood vessels causing intense pain
- Can lead to kidney or heart failure, stroke, rheumatism, or paralysis
- HbS is indigestible to malaria parasites so gene persists despite its harmful effects to the homozygous effects to the homozygous individuals.
57
What are the abnormalities of Leukocyte count?
- Leukopenia, leukocytosis, and leukemia
58
What is Leukopenia?
- low WBC count (<5000)
- causes: radiation, poisons, infectious disease
- effects: elevated risk of infection
59
What is Leukocytosis?
- high WBC count (>10,000)
- causes: infection, allergy and disease
- differential count distinguishes % of each cell type
60
What is Leukemia?
- cancer of hemopoietic tissue
- myeloid and lymphoid: uncontrolled WBC production
- acute or chronic (very fast) : death in either months or years
- effects: normal cell % disrupted, patient subject to opportunistic infection, anemia and impaired clotting.
61
What are Platelets?
- small fragments of megakaryocytes (produced in bone marrow)
- normal platelet count (130,000-400,000)
- contribute less than WBCs to blood volume
62
What is thrombopoiesis?
- production of platelets
- thrombo= clotting
- contain "granules" and organells
- amoeboid (pseudopod) movement and phagocytosis
63
What are platelet functions?
- secrete
- clotting factos
- growth factors for endothelial repair
- vasoconstrictors in broken vessels
- form temporary platelet plugs
- dissolve old blood clots
- phagocytize bacteria
- attract WBCs to sites of inflammation
64
Steps of Hemostasis: The control of bleeding
1. Vascular spasm
2. Platelet plug formation
3. Blood clotting
- effecting at closing breaks in small vessels
- 3 hemostatic mechanisms: all involve platelets.
65
What is vascular spasm?
- prompt constriction of a broken vessel
- most immediate protection against blood loss
66
What are the causes of vascular spasm?
- pain receptors: some directly innervate blood vessels to constrict (vasoconstriction)
- smooth muscle injury: constrict when hurt
- platelets release serotonin (vasoconstrictor)
67
What are the effects of vascular spasm?
- constriction of a broken vessel
- pain receptors: short duration (minutes)
- smooth muscle injury: longer duration
- provides time for other two clotting pathways
68
True or False: Endothelium is very smooth because it is coated with prostacyclin (a platelet repellant)
True
69
What is the hemostasis platelet plug formation?
- broken vessel exposes collagen
- platelets; pseudopods stick to damaged vessel and other platelets; pseudopods contract and draw walls of vessel together forming a platelet plug
- Platelets degranulate releasing a variety of substances (serotonin is a vasoconstrictor, ADP attracts and degranulates more platelets, Thromboxane A2 promotes platelet aggregation, degranulation, and vasoconstriction.
- positive feedback cycle (until break in vessel is sealed)
70
What is coagulation?
- Clotting; last and most effective defense against bleeding
- conversion of plasma protein fibrinogen into insoluble fibrin threads to form framework of clot
71
What are Procoagulants?
- Clotting factos; usually produced by the liver; are present in plasma at all times
- activate one factor and it will activate the next to form a reaction cascade
72
What is the extrinsic pathway?
- factors released by damaged tissues begin cascade
- initiated by release of tissue thromboplastin from damaged tissue
- calcium is required for pathway
73
What are the intrinsic pathways?
- factors found in blood begin cascade (platelet degranulation)
- initiated by platelets releasing Hagemen factor.
- calcium required for pathway
74
What is rapid clotting?
- each activated cofactor activates many more molecules in next step of sequence
75
What does the activation of factor X do?
- leads to production of prothrombin activator
76
What does the Prothrombin activator do?
- converts prothrombin to thrombin
77
What does thrombin do?
- converts fibrinogen into fibrin
- positive feedback: thrombin speeds up formation of prothrombin activator.
78
What is a platelet-derived growth factor?
- secreted by platelets and endothelial cells (facilitate healing)
- mitotic stimulant for fibroblasts and smooth muscle to multiply and repair the damaged vessel
79
What is fibrinolysis?
- dissolution of clot
- plasminogen (inactive protein) converted into plasmin (a fibrin- dissolving enzyme or clot bust
80
What is platelet repulsion?
- platelets do not adhere to prostacyclin-coating
81
What is thrombin dilution?
- activates clotting cascade
- normally diluted by rapidly flowing blood
- heart slowing in shock can result in clot formation
82
What is a natural anticoagulant?
- antithrombin produced by the liver deactivates thrombin before it can act on fibrinogen
83
What is heparin?
- secreted by basophils and mast cells interferes with formation of prothrombin activator
84
What disorders have insufficient clotting?
- thrombocytopenia and hemophilia
85
What is thrombocytopenia?
- platelet count below 100,000 (bruise easily)
86
What is hemophilia?
- genetic lack of any clotting factor affects coagulation
- sex-linked recessive in males (inherit from mother)
- physical exertion causes bleeding and pain
87
What is thrombosis?
- abnormal clotting in unbroken vessel
- most likely to occur in leg veins or inactive people
88
What is a pulmonary embolism?
- clot may break free, travel from veins to lungs
89
What is an embolus?
- anything that can travel in the blood and block blood vessels (clot, air bubbles)
90
What is infarction?
- tissue death
- may occur if clot blocks blood supply to an organ (MI or stroke)
91
What is Disseminated intravascular coagulation?
-Widespread clotting in unbroken vessels
- caused by septicemia (bacteria in blood) or cardiac arrest (heart stops beating causing the blood to stop moving, then clotting factors get activated)
92
How can we prevent clots?
- Vitamin K is required for formation of clotting factors
- Vitamin K antagonists can be used to "thin" the blood and prevent clotting
- Coumarin, warfarin, Vitamin K: blood thinners
- Aspirin suppresses thromboxane A2
- Dissolving clots that have already formed
- Streptokinase: enzyme made by streptococci bacteria
- Tissue plasminogen activator: works faster, is more specific, and now made by transgenic bacteria
