Blood Flashcards
What are the three components of blood? What are they more commonly known as?
- Erythrocytes: Red blood cells
- Leucocytes: White blood cells
- Platelets
What is the pH of blood?
7.35-7.45
What are the two colors blood can be? What are the conditions for blood to be these colors?
Oxygenated blood is scarlet or bright red, and deoxygenated blood is a very dark red or even blue.
How much blood is in average human bodies?
Roughly 8 percent of body weight, 4-5L in females and 5-6L in males.
What are the three main subcategories of blood function?
Distribution, regulation, and protection
What does blood distribute?
- Oxygen and nutrients
- Metabolic Wastes
- Hormones
What 3 things do blood regulate?
- Temperature (distribution, dissipation, conservation)
- pH in body tissues (plasma proteins, bicarbonate reserves)
- Adequate fluid volume
What does blood protect against?
- Blood loss (plasma and platelets)
- Infection (Antibodies, compliment, WBCs)
What is the blood pH buffer reaction?
CO2+ H20 <-> C2HCO3 <-> HCO3^- + H^+
What is the most dense part of blood (bottom when spun in the centrifuge)? What percentage of the blood does it make up?
The Erythrocytes make up roughly 45% of the blood.
What is the most least dense part of blood (top when spun in the centrifuge)? What percentage of the blood does it make up?
Plasma makes up roughly 55% of the blood.
What is blood plasma?
It is 90 percent water with solutes.
What are plasma proteins?
They are functional proteins that are in blood.
What is the most common plasma protein?
Albumin (60% of plasma)
Where are plasma proteins produced? What is the exception to the rule?
They are produced in the liver, however gamma globulins are antibodies and are produced by cells of the immune system.
What are the roles of albumin?
- It is a carrier of molecules
- It is a buffer
- It is an osmotic protein
What is the major osmotic ion? What charge does it have?
Na+
What are the only complete cells in the blood? Why?
Leukocytes have nuclei as opposed to erythrocytes and platelets.
What is the size and shape of a red blood cell?
It is a biconcave disc about 7.5 micrometers in diameter.
What is the composition of an erythrocyte?
It is a “bag of hemoglobin” with other proteins to maintain permeable membrane and cell shape
What does spectrin do?
It allows erythrocytes to change their shape and squeeze through narrow capillaries/reassume normal shape.
What are the three special characteristics of erythrocytes that optimize function?
- Small size and shape gives a large SA to V ratio.
- It is mostly hemoglobin (97% of non-fluid composition)
- Generate ATP anaerobically, do not use oxygen to meet their own needs.
Do red blood cells transport CO2?
Yes approximately 20 percent.
How are rate of blood flow and RBC count related?
They have an inverse relationship
What is the composition of a globin protein?
It is made of 4 polypeptide chains, two alphas (lighter) and two betas (darker).
What are the meanings of the two words that make up hemoglobin?
Heme = red pigment
Globin = protein
What atom is in the middle of each heme group? Why is it imporant?
Iron can reversible bind to oxygen. (Can hold onto but can also release into the surrounding area)
Why is hemoglobin contained in erythrocytes?
There is a lot of it, so the packaging of hemoglobin keeps it from fragmenting and getting lost, and also keeps it from directly affecting blood osmotic pressure and viscosity.
What do we call hemoglobin molecules with and without oxygen?
OxyHb and deoxyHb
What molecules bind where on a hemoglobin molecule?
Oxygen binds to the heme group and carbon dioxide binds to the globin protein
What do we call the carbon dioxide bound to globin?
carbaminohemoglobin
What is the starting point cell for the production of blood components?
Hematopoietic stem cells, or hemocytoblasts
Define hematopoeisis
It is the general term for the production of formed elements in the red bone marrow
What is the term for the hematopoiesis specifically of erythrocytes?
Erythropoiesis.
What is the name of the committed cell in the erythropoiesis process?
The proerythroblast
Simple describe the developmental pathway of erythrocytes.
The proerythroblasts fill with hemoglobin and then eject the nucleus
What is the name of the entity at the end step of erythropoiesis that is essentially an erythrocyte that has not moved out into the circulatory system?
A reticulocyte
What is the structural difference between an erythrocyte and a reticulocyte?
A reticulocyte has some additional protein synthetic machinery
How long does erythropoiesis take?
Around 15 days
What does a reticulocyte count indicate? What is a healthy range?
A reticulocyte count of roughly 1-2 percent of erythrocytes indicates a solid ability of the bone marrow to produce new erythrocytes.
What are the two abnormalities associated with erythropoiesis.
Anemia = too few RBCs
Polycythemia = too many RBCs
What is a healthy production rate of RBCs?
More than 2 million/second
What is EPO?
Erythropoietin is a glycoprotein hormone responsible for a higher RBC count.
Where is the primary site of EPO production?
The kidneys
When is EPO release stimulated?
Hypoxic conditions eg.
1. hemorrhage/RBC destruction
2. High altitude
3. Increased Demand
How long after EPO production does RBC count rise?
1-2 days
What is a risk of EPO abuse in athletes?
Increased blood viscosity and dehydration can cause stroke, clotting, or heart failure
What is the effect of testosterone on EPO production?
It is stimulating
Why would women have a lower hematocrit than men?
- No testosterone
- Lose blood through menstruation
What are the two dietary requirements for erythropoiesis?
Iron and B vitamins
What types of proteins store iron to keep it from being toxic free iron in the blood? Where are they found?
Ferrin and hemosiderin are found in the liver, spleen, and bone marrow
What is iron bound to in the blood?
Transferrin
Where is most iron found in the body? How much percent of the body’s iron is found here?
Hemoglobins (65%)
How do we lose iron?
Feces, sweat, urine, menstruation
What two dietary components other than iron are necessary for DNA synthesis?
Vitamin B12 and folic acid
Where is the RBC graveyard?
The spleen
What is the usual lifespan of a RBC?
100-120 days
What path does the heme follow once the RBC is degenerating?
Once the iron is recycled from the RBC, the heme becomes bilirubin which then becomes stercobilin or urobilinogen
What happens to the globin in cell decomposition?
The amino acids are recycled
How is anemia defined?
The reduced oxygen carrying capacity of blood
What are the three probable causes of anemia?
- Not enough normal RBCs produced.
- Episode of significant blood loss
- RBCs are being destroyed too quickly ie. sickle cell anemia
What is Hct?
Hematocrit is the percentage of RBC in the blood.
What are the three types of polycythemia?
- polycythemia vera : true polycythemia due to a cancerous mutation in the bone marrow
- Secondary polycythemia is the result of high altitude/severe respiratory disease because oxygen is limited and so EPO is released and elevated RBC count.
- Artificial polycythemia is blood doping
What is the committed developmental cell of a platelet called?
A megakaryoblast
How are platelets described formationally?
They are cytoplasmic fragments of megakaryocytes
What do platelets contain?
Purple staining granules that contain clotting factors and enzymes
What is the lifespan of a platelet?
roughly 10 days
What hormone is responsible for the formation of platelets? Where is it primarily found?
Thrombopoietin is formed in the liver
What are the three phases of hemostasis?
1, Vascular spasms
2. Formation of a platelet plug
3. Coagulation
What is the point of vasoconstriction?
Slow blood flow, making it easier for the platelets to interact
What triggers vasoconstriction?
Damage to vessel walls, release of chemicals by platelets and endothelial cells
What two substances prevent the usual sticking of platelets? What produces them?
NO and PGI2 (prostacyclin) are produced by endothelial cells
What causes platelets to swell and stick?
Collagen
What plasma protein adheres to exposed collagen?
Von Willebrand factor
What is degranulation?
Release of the clotting factors that are present in the platelets
What three platelet products promote clumping?
- ADP (aggregation/degranulation)
- Serotonin (Vascular spasm and aggregation)
- Thromboxane A2 (Vascular spasm and aggregation)
What are the two pathways of hemostasis? What product is created at the end of phase 1?
There is the intrinsic and extrinsic pathways that both create prothrombin activator.
What happens in phase 2 of hemostasis?
Prothrombin is converted to thrombin
What happens in phase 3 of hemostasis?
Thrombin catalyzes the conversion of fibrinogen into fibrin into fibrin threads.
What is the name for stages 2 and 3 of hemostasis?
Coagulation
What are the differences between the intrinsic and extrinsic pathways to coagulation?
Intrinsic: outside the body (in a test tube) or in a slightly damaged vessel, it is slower, has a larger capacity
Extrinsic: In response to damage, release of tissue factor, faster, has a limited capacity
What is the similarity of materials that activate blood clotting?
They all have negative charges.
What factor triggers the release of prothrombin activator?
Factor 10 (X)
What happens with factor 7 as the extrinsic pathway is taken?
It activates the intrinsic pathway with a higher capacity.
How long after the damage occurs does clot retraction happen?
30-60min
Why does clot retraction happen?
Actin and myosin pulls on surrounding fibrin strands.
What is the fluid squeezed out in the clot retraction process called?
Serum
What factor is released during degranulation to activate repair associated with blood vessel walls?
PDGF
What factor is responsible for covering the area of damage during the healing process?
VEGF
What is fibrinolysis?
The removal of a clot when it is no longer needed.
What is the key enzyme and enzyme precursor for fibrinolysis?
Plasmin (plasminogen)
What activates plasminogen?
tPA (tissue plasminogen activator)
How long after damage dos fibrinolysis begin?
Within 2 days
What are the two homeostatic mechanisms to control the size of the clot?
- The removal of coagulation factors
- Inhibition of activated clot factors
What are the two balancing types of factors in a clot?
Procoagulation factors and anticoagulating factors
Why are vascular spams in response to injury good for clotting?
If the blood is flowing, it washes away Procoagulation factors
What are the 6 factors that limit clot growth?
- Flowing blood washes away procoagulants
- Thrombin is absorbed onto fibrin threads
- Antithrombin III inactivates escaping thrombin
- Antithrombin III and protein C inactivates intrinsic pathway procoagulants
- Heparin basophils and mast cells enhance activity of antithrombin III and inhibit the intrinsic pathway
- Smooth endothelial lining of undamaged blood vessels prevents undesired clotting as well as endothelial NO and prostacyclin
What is a thrombus?
A clot that persists in an unbroken blood vessel.
What is an embolus?
A thrombus that has broken free and can get stuck in a smaller diameter vessel.
What does Aspirin do?
It inhibits a procoagulant.
What are the three main examples of bleeding disorders?
- Thrombocytopenia
- Impaired liver function
- Hemophilias
What would cause thrombocytopenia?
Any condition harmful to bone marrow that lowers the platelet count
What are petechiae?
tiny areas of damage to capillaries that are visible as the clotting has not kicked in
Why is the liver associated with coagulation?
The liver is responsible for some Procoagulation enzymes. Bile is also needed to absorb vitamin K which is important for clot formation.
What is hemophilia?
It is a hereditary bleeding disorder associated with missing factors.
What does hemophilia A lack? Hemophilia B? What type of inheritance are hemophilia genes?
Factor 8, and Factor 9, and they are sex linked genes.
What are the two ways that the body compensates for blood loss?
- There is a generalized vasoconstriction
- There is an increase in erythropoiesis.
What are the thresholds of blood loss?
15-30 percent blood loss = weakness/pallor
30+ percent blood loss = induce shock
In a case of anemia, what blood would be transfused?
Blood with packed red cells would help for anemia.
For substantial blood loss or thrombocytopenia, what kind of transfusion would be given?
A whole blood transfusion.
How is donated blood preserved?
It is mixed with an anticoagulant, which is citrate dextrose - which soaks up calcium
In type A blood, which antigens and which antibodies are present?
Type A blood has type a antigens and type b antibodies
In type AB blood, which antigen and antibodies are present?
Both antigens are present, and no antibodies are present
In type O blood, which antigen and antibodies are present?
No antigens are present, so both antibodies are present
What blood types are more or less common?
AB and B are less common, and O and A are more common
What Rh factor is important for the Rh positive and negative readings?
RhD
What happens if you are Rh negative?
You have no antibodies to Rh factor
What happens to an Rh negative individual when exposed to Rh positive blood?
The blood becomes sensitized and the immune system will become activated to attack Rh positive blood.
What are Rh negative mothers with Rh positive babies treated with?
RhoGAM
What is disease of a newborn with Rh positive blood called when it is attacked by the mothers antibodies?
Erythroblastosis fetalis
What is another word for antibodies in the blood?
Agglutinins
What is agglutination?
the clogging of small blood vessels
What is another problem with a problematic transfusion other than agglutination?
Clumped RBCs are destroyed or ruptured and release a bunch of hemoglobin
What is the overall result of a poor transfusion?
- blocked blood flow to tissues
- Reduced O2 carrying ability of blood
- Hemoglobin precipitates and clogs kidney tubules, which can be treated with alkaline fluid and diuretics
What is the name of a transfusion someone takes out of themselves prior to a procedure?
An autologous transfusion.
How is blood typing done?
Drops of blood are placed on slides with anti a or anti b serum and we look for signs of agglutination
