Blood & Body Fluids Facts Flashcards
Where do thrombin and vWf come from in the platelet adhesion step of platelet plug formation in haemostasis?
Thrombin: coagulation cascade (feedback)
vWf: megakaryocytes, endothelial cells, platelets
What are the components of tenase?
VIIIa, IXa, Ca++
How does Protein C, and its cofactor Protein S, prevent unnecessary coagulation?
Target Va and VIIIa to prevent clot formation (Va: forms prothrombinase; VIIIa: forms tenase)
Total Transcellular fluid volume in typical adult human
negligible
How are thromboxane A and prostacyclin (PGI2) synthesized? (main enzymes and intermediates)
From Phospholipids
Via phospholipase
To Prostaglantin H2 (PGH2)
To thromboxane A (damaged cells) or prostacyclin (intact cells)
Describe the characteristics of the Intrinsic Pathway of blood coagulation & clot formation in haemostasis.
Ongoing during tissue regeneration
Uses components that are in the blood, or have precursors in the blood
Name the 7 types of plasma proteins
Albumin Lipoproteins Glycoproteins Coagulation Factors Immunoglobins Complements Hormones
How does low tissue O2 affect erythropoiesis?
signals to kidney to incr. EPO release, which stimulates erythropoiesis, increasing tissue O2
What role does prothrombinase play in the Common Pathway of blood coagulation & clot formation in haemostasis?
Activates Prothrombin -> Thrombin
Protein content level of ICF
High
What effect does ADP release have on cells adjacent to an injured site in a blood vessel?
Causes release of prostacyclin (prostaglandin inhibiting platelet aggregation) and NO (vasodilator)
Which factor targets Ca++ to prevent unnecessary coagulation?
Ca++ chelators
Why does haematopoietic activity of femur & tibia bone marrow fall off sharply during childhood?
Bones need the density for growth; pass duties to bones that grow less
What type of coagulation defect causes a defiency in prothrombin, VII, IX, X?
Vitamin K deficiency
What role does plasmin play in haemostasis?
Fibrinolysis:
Stable fibrin -> soluble fragments
What causes haemophilia?
Inherited
Describe platelet adhesion during platelet plug formation in haemostasis.
- Glycoproteins constitutively expressed on endothelial and subendothelial cells
- Adhesion factor (thrombin, integrin, vWf) release by subendothelial cells
=> Platelets bind exposed collagen & each other
What are the three biological phases of haemostasis?
- Initiation - Extrinsic pathway makes thrombin
- Amplification - Thrombin action: platelet activation, ^ prothrombinase activity, ^ tenase formation
- Propagation - Distal sites enhance tenase formation
What is involved in the platelet aggregation step of platelet plug formation in haemostasis?
Platelet activation promotes aggregation; ADP & fibrinogen key to forming unstable platelet plug
What are the components of prothrombinase?
Va, Xa, Ca++
Haemostasis is an integrated system. What causes Haemostasis?
Platelet plug formation
Clot formation
Which physical factor prevents unnecessary coagulation, and how?
Blood vessel integrity: -ve glycocalyx prevents -ve platelet adhesion
Which factor targets IXa (only) to prevent unnecessary coagulation?
alpha-Protease inhibitor
Which bones’ marrow play a key role in haematopoiesis as people age?
Vertebrae, ribs, sternum, pelvis
How do heparin and heparan sulphate prevent unnecessary coagulation in vivo?
Stimulate AT III (antithrombin III)
What happens to fibrinogen in the Common Pathway of blood coagulation & clot formation in haemostasis?
Hydrolyzed by thrombin to fibrin monomers and fibrinopeptides
Spontaneously polymeryzes to fibrin polymers
Which clotting factors are not produced sufficiently when there is a Vitamin K deficiency?
prothrombin, VII, IX, X
Which factor targets the TF.VIIa.Ca++ complex to prevent unnecessary coagulation?
Tissue factor pathway inhibitor (TFPI)
Major anion(s) in ECF: ISF
Cl-
What type of stem cells do pluripotent stem cells become if they are going to become thrombocyte?
Myeloid
Types of Granulocytes
Basophil
Neutrophil
Eosinophil
What happens to monocytes once they mature?
They enter the reticuloendothelial system:
- enter tissue and stays (becomes “fixed macrophage”)
- signal
- breaks off (becomes “mobile macrophage”)
What role does XIIIa play in the Common Pathway of blood coagulation & clot formation in haemostasis?
Stabilizes cross-links between fibrin polymers in the clot
In which pathways of Haematopoiesis is Erythropoietin involved?
Myeloid Stem Cell growth into Erythrocytes & Thrombocytes
Which factors do PAI1 and PAI2 act on?
t-PA, u-PA
What results from a IX deficiency?
Type B haemophilia (coagulation defect)
Total body fluid volume in normal adult human
42L
What role does TF play in the Extrinsic Pathway of blood coagulation & clot formation in haemostasis?
Binds and non-proteolytically activates VII;
Acts with VIIa and Ca++ to convert X->Xa (proteolytically)
Which factor increases blood flow & prevents platelet aggregation/adhesion/activation & causes vasodilation to prevent unnecessary coagulation?
Endothelial PGI2 (prostacyclin)
How does alpha-Protease Inhibitor prevent unnecessary coagulation?
Targets IXa (forms Tenase)
Name the 6 main regulators of erythropoiesis
- Tissue O2 levels
- EPO
- Cytokines (GM-CSF, IL-3)
- Iron & copper
- Folic acid & Vitamin B12
- Sex steroids
What are the 4 events that occur during formation of a platelet plug in haemostasis?
(“4 PAs”)
a. Platelet Adhesion
b. Platelet Activation
c. Platelet Aggregation
d. Primary arrest of bleeding
Typical erythrocyte life span, and reason
120 days; can’t synthesize protein & hemoglobin gets oxidized
What happens to fibrin polymers in the Common Pathway of blood coagulation & clot formation in haemostasis?
They are stabilized with cross-linkages, catalyzed by XIIIa
What happens to iron in erythrocytes?
Recycled: Macrophage breaks down erythrocyte and release Fe2+ back to plasma to be re-oxidized by Caeruloplasmin…
Haemostasis is an integrated system. What causes Clot formation?
Coagulation cascade
Platelet adhesion/activation/aggregation
What do platelets release from the alpha granules during the platelet activation step of platelet plug formation in haemostasis?
Thromboxane A (for platelet aggregation)
factor V (clotting factor)
fibrinogen (for platelet aggregation)
vWf (promotes platelet adhesion)
What does a macrophage break haemoglobin down into, and what happens to those components?
- Globin -> amino acids; recycled
- Iron -> back to blood & transferrin; recycled
- Haem -> bilirubin -> in plasma -> albumin transports to liver -> bile -> secrete into intestine; excreted
What role do negative charges on activated platelets play in the Intrinsic Pathway of blood coagulation & clot formation in haemostasis?
Activate XII -> XIIa (slowly)
Total Plasma volume in typical adult human
3L
How does EPO affect erythropoiesis?
Prohibits BFU-E, CFU-E apoptosis (particularly CFU-E)
What are the components of the complex that activates X in the Intrinsic Pathway of blood coagulation & clot formation in haemostasis? Does it have a name?
VIIIa, IXa, Ca++
Name: Tenase
How is blood volume calculated (from known plasma volume)?
- Use centrifugation to calculate % haematocrit, % plasma
2. V_blood = V_plasma / %plasma
Describe the Intrinsic Pathway of blood coagulation & clot formation in haemostasis.
- Slow conversion of XII->XIIa by contact with negative charges on activated platelets; cofactor: High Molecular Weight Kininogen (HMWK)
- XIIa feedsback to activation: stimulates prekallikrein->kallikrein, kallikrein proteolytically converts XII->XIIa
- XIIa.HMWK converts XI->XIa.HMWK
- XIa.HMWK converts IX->IXa
- (separately) vWf releases VIII
- thrombin converts VIII->VIIIa
- VIIIa.IXa.Ca++ (“tenase”) converts X->Xa
Name the four roles of thrombin in haemostasis.
- enhance platelet aggregation
- Hydrolyze fibrinogen -> fibrin monomers & fibrinopeptides
- Convert XIII -> XIIIa
- Feedback (+) to increase production of VIIIa (-> tenase), Va (-> prothrombinase)
Major anion(s) in ECF: plasma
Cl-
Generally describe the process of haem synthesis
Porphyrins are synthesized/transformed in the mitochondria & cytoplasm, and eventually bind Fe2+ in the mitochondria to form haem
Shape of erythrocytes, and reason
Deformable biconcave disk; high SA:volume ratio for gas exchange, deformable to fit through capillaries
What is involved with the Humoral Substance Release portion of Vasoconstriction in haemostasis?
Serotonin (vasoconstrictor) is released by platelets or as a result of coagulation
Two main compartments of body fluids in humans & %
ICF (67%)
ECF (33%)
What is involved in the Platelet Activation step of platelet plug formation in haemostasis?
- Platelets form pseudopodia
- Platelets release materials in dense granules (Ca++, ATP, serotonin, ADP)
- Platelets release materials in alpha granules (thromboxane A, factor V, fibrinogen, vWf)
** are linked
Which organs are hematopoietic, and when?
Yolk sac: early fetal development
Liver/spleen: mid-fetal development
Bone marrow: begins in mid-fetal development (4mo), decreases quickly in tibia & femur; decreases slowly in vertebrae/ribs/sternum/pelvis
2 main functions of blood & body fluids
Transport, Protection
What does bone marrow contain that allows it to be haematopoietic?
Pluripotent stem cells - can become erythrocytes, leukocytes, or thrombocytes
How does Endothelial NO prevent unnecessary coagulation?
Prevents platelet adhesion & aggregation
Vasodilator
Protein content level of ECF: plasma
medium
What two compounds act as vasodilators to prevent unnecessary coagulation in intact blood vessels?
- Endothelial PGI2 (prostacyclin)
2. Endothelial NO
What type of stem cells do pluripotent stem cells become if they are going to become monocytes?
Myeloid
How does GM-CSF/IL-3 affect erythropoiesis?
Promote erythrocyte development from precursors
Blood components
Plasma Formed Elements RBCs (Erythrocytes) WBCs (Leukocytes) Platelets (Thrombocytes)
What happens to mature erythrocytes (after forming from reticulocytes)?
Released from bone marrow, mature in 1-2 days
Name the three types of glycoproteins in the plasma
Transferrin
Haptoglobins
Caeruloplasmin
Describe the general process of erythrocyte breakdown by the reticuloendothelial system
Mobile macrophage takes up erythrocyte & breaks down membrane and haemoglobin
What is PAI-2 and what does it do?
Placental Plasminogen Activator Inhibitor; prevents plasminogen -> plasmin
What processes are involved in blood coagulation & clot formation in haemostasis?
Extrinsic Pathway, Intrinsic Pathway, Common Pathway
Name three Ca++ chelators
Oxalate, EDTA, Citrate
Which factor targets Va and VIIa to prevent unnecessary coagulation?
Protein C and its cofactor, Protein S
Transport pathway for nutrients in body fluids
Capillaries -> Interstitial fluid -> ICF
Describe the Storage step of iron metabolism
Excess iron is incorporated into ferritin, which is stored in the liver
Erythrocytes: nucleus?
no
What roles does XIIa.HMWK play in the Intrinsic Pathway of blood coagulation & clot formation in haemostasis?
Feedback on prekallikrein -> kallikrein, to make more XIIa.HMWK
Activate XI -> XIa.HMWK
What are the two events that occur during Vasoconstriction in haemostasis?
- Local contraction
2. Humoral substance release
How do iron and copper affect erythropoiesis?
Iron helps form haem, copper helps caeruloplasmin oxidize Fe2+ -> Fe3+
Characteristics of Reticulocyte
Loses nucleus
Only a few ribosomes & Golgi remnants left in cytoplasm
Which plasma proteins are involved with maintaining osmotic pressure?
Albumin
What type of stem cells do pluripotent stem cells become if they are going to become Lymphocyte?
Lymphoid
How does a clot form in haemostasis?
Fibrin lattice traps erythrocytes, leukocytes
Name 2 characteristics of erythrocytes related to CO2 transport
High [carbonic anhydrase] to convert CO2 -> HCO3-
High anion permeability to allow Cl-, HCO3- exchange
Total ICF volume in typical adult human
28L
Describe thrombocytes, in terms of shape, nucleus, and membrane
Disk-shaped, but can changed w/ pseudopodia
No nucleus
Have “fuzzy” glycocalyx (negatively charged)
Roles of blood & body fluids in transport (5)
“RENCH”
Respiration (O2, CO2)
Excretion (waste to kidneys, intestines, lungs)
Nutrients (from gut to tissues; between organs)
Communication (hormones)
Homeostasis (water & control hormones)
What role does VIIa play in the Extrinsic Pathway of blood coagulation & clot formation in haemostasis?
Combines with TF, Ca++ to convert X->Xa
What are the attendant ions for Na+, and where are they used?
Cl-, HCO3-; in ECF
What do platelets release from the dense granules during the activation step of platelet plug formation in haemostasis?
Ca++, ADP, ATP, serotonin
Types of Leukocytes
Lympocytes Granulocytes Basophil Neutrophil Eosinophil Monocytes
Describe the structure of haemoglobin
4 polypeptide (globin) chains: 2 alpha, 2 ß
Each globin chain holds 1 haem molecule in the middle (4 haem total)
Each haem molecule has 1 Fe2+ ion in the center, which binds 1 molecule O2 (4 O2 total)
Which factors are involved with the Intrinsic Pathway of blood coagulation & clot formation in haemostasis?
vWf VIIIa kallikrein (prekallikrein) XIIa.HMWK XIa.HMWK IXa Ca++
Function of albumin in plasma
Maintain oncotic pressure, bind/transport drugs & other molecules
Describe a senescent erythrocyte
Decreased membrane continuity
Decreased enzyme activity
Increased [methaemoglobin] (oxidized Hb)
Describe clot retraction in haemostasis and the result.
Serum oozes out of fibrin lattice (erythrocytes, leukocytes trapped), bringing the tissue edges together for repair
In which pathways of Haematopoiesis is G-CSF involved?
Myeloid Stem Cell growth into Granulocytes
Which factor breaks down stable fibrin into soluble fragments?
Plasmin
How are thrombocytes formed, and what factor is involved?
Fragments that peel off megakaryocytes in marrow; stimulated by liver release of thrombopoietin, which increases megakaryocyte synthesis
Transport pathway for wastes in body fluids
ICF -> ISF -> lymph/blood capillaries
How do folic acid & Vitamin B12 affect erythropoiesis?
Act as cofactors for erythropoietic enzymes
What type of stem cells do pluripotent stem cells become if they are going to become granulocytes?
Myeloid
Major cation(s) in ECF: ISF
Na+
Describe the (Reduction &) Incorporation step of iron metabolism
Reduce Fe3+ to Fe2+, incorporate it into haem in mitochondria, and then incorporate haem into haemoglobin in the cytoplasm
Describe the mechanism of vasoconstriction in haemostasis
Initial neurogenic spasm (~60s), then myogenic spasm (~20-30min)
Which types of plasma proteins are involved with the plasma Immune system?
Immunoglobins, complements
What initially activates XII in the Intrinsic Pathway of blood coagulation & clot formation in haemostasis?
Contact with negative charges on the activated platelets
Which 6 compounds/classes act as in vivo anticoagulants?
- Antithrombin III (AT III)
- Heparin & Heparan sulphate
- Tissue factor pathway Inhibitor (TFPI)
- Thrombomodulin
- alpha-protease inhibitor
- Protein C and co-factor, Protein S
Units of solute concentration & their relation
- mmol/L
- meq/L (mmol/L x z; z=valence)
- mosmol/kg H2O (# of osmotically active solutes x mmol/kg H2O)
- mosmol/L H2O (# of osmotically active solutes x mmol/L H2O)