Unit 1 - The Blood (Midterm #1) Flashcards
What are the 5 functions of blood?
- Transport (gases, nutrients, wastes, etc)
- Stabilizing pH and electrolyte composition
- Restricting fluid loss (through clotting)
- Defending body against toxins and pathogens (WBCs)
- Stabilizing body temperature
Does blood have a higher or lower viscosity than water?
Higher viscosity than water
- it is thicker, moves more slowly
What is the main determinant for blood viscosity?
The number of red blood cells in the blood
What happens if the blood has a high osmolarity?
Big dissolved particles in the blood cannot leave the blood vessel, fluid will flow INTO the blood vessels to try to dilute the blood concentration.
- Results in high blood pressure
What happens if the blood has a low osmolarity?
Big dissolved particles in the blood cannot leave the blood vessel, fluid will flow OUT of the blood vessels to try to dilute the interstitial spaces and into the tissues
- Results in low blood pressure
What could result if there is a significant drop in blood osmolarity?
Edema!
- fluid enters the tissues, results in swelling
Define Hypovolemia.
Low blood volume
(
Define Normovolemia.
Normal blood volume
4 - 6 litres
Define Hypervolemia.
Excessive blood volume
> 6 litres
What happens to blood pressure if the patient is hypovolemic? Hypervolemic?
Hypovolemic = low blood pressure (excess loss of fluid), tissues might not be well perfused Hypervolemic = high blood pressure (too much fluid)
Why might a patient have more or less blood than is considered “normal”?
Blood volume varies with body weight
- a large patient will have a higher blood volume
- a small patient will have a smaller blood volume
What are the formed elements of blood?
- Cells
2. Cell fragments
What does plasma consist of?
- Water
- Electrolytes
- Proteins
- Other dissolved and suspended particles
What is the ratio of whole blood to plasma?
Approx 55% plasma
Approx 45% whole blood
What makes up 92% of plasma?
Water!
How is blood plasma different from interstitial fluid?
- It has a higher amount of dissolved oxygen in it
- It has a large number of dissolved proteins in it
How is the ration of whole blood:plasma different in men and women?
Men have less plasma relative to whole blood (higher oxygen carrying capacity)
Women have more plasma relative to whole blood
Why are pH changes in plasma lower than in interstitial fluid?
Because of the buffering capability of the proteins in the blood
What are the 4 different kinds of proteins found in the blood plasma?
- Albumins
- Globulins
- Fibrinogen
- Regulatory proteins
What is the most prevalent protein found in blood plasma?
Albumins (60%)
- Globulins (35%)
- Fibrinogen (4%)
What is the function of Albumins?
- Contributes to oncotic pressure (ability to draw water INTO the bloodstream)
- Attaches to lipids to form lipoproteins
What is the function of Globulins?
Immunoglobulins attack foreign proteins
What is the function of Fibrinogen?
Important in blood clotting
What is leftover if you remove fibrinogen from plasma?
Serum
What does hematocrit (hct) measure?
Percentage of whole blood (RBCs + plasma) occupied by cellular components
- closely approximates volume of RBCs
What is the ratio of RBCs to WBCs?
1000 RBC to 1 WBC
Do men or women typically have a higher hematocrit?
Men!
- more RBC in circulation
- higher oxygen carrying capacity
Why should athletes train at high altitudes?
- Air pressure is lower, amount of available oxygen is lower
- The body produces more RBCs to compensate of the low levels of oxygen
- When athletes come down to sea level to compete, they have very high level of hematocrit = high oxygen carrying capacity
= higher performace
What is the function of RBCs?
Transport oxygen and carbon dioxide (in cytoplasm of RBCs)
What is the importance of the biconcave disc of RBCs?
- Provides a large surface area compared to volume ratio
- The higher the surface area, the higher the binding ability of oxygen to the cell
What are the main structural properties of RBCs?
- Lack mitochondria, ribosomes, and nuclei
- Unable to perform normal maintenance
- Degenerate after approx. 120 days
- Recycled by phagocytes
What is the most prevalent RBC protein?
Hemoglobin (95% of RBC proteins)
- 5% of RBC proteins are enzymes involved in the binding of hemoglobin
What is the function of hemoglobin?
Gives the RBC the ability to transport oxygen
What is hemoglobin composed of?
- Two alpha chains
- Two beta chains
- Each chain holds 1 Fe+2 heme group
How many oxygen molecules can 1 hemoglobin molecule hold?
4!
- 1 oxygen molecule binds to each Fe+2 molecule in each chain
Why is the O2 sat on patients not 100%?
Each chain of the hemoglobin doesn’t ALWAYS bind optimally (all 4 sites are occupied)
- Sometimes only 1, 2, or 3 sites are occupied
What parts of hemoglobin are recycled? What parts are destroyed?
- Alpha and beta chains AND Fe+2 are recycled
- Heme portion is destroyed
Where are most RBCs destroyed?
In the capillaries of the spleen
What gives feces and urine their color?
Bilirubin!
- result of RBCs being destroyed.
Describe the steps involved in the process of how RBCs are broken down.
- Macrophages in the spleen destroy the RBC
- Amino acids and Fe+2 are recycled
- Heme is broken down into bilirubin
- Liver detoxifies bilirubin –> conjugated bilirubin
- Excreted in feces or urine
What is the difference between unconjugated and conjugated bilirubin?
- UNconjugated bilirubin = toxic b/c it is insoluable; produced by WBC (macrophage) and CANNOT be excreted! = Jaundice
- Conjugated bilirubin = soluable; able to be excreted by the kidneys
What are the two fates for unconjugated bilirubin?
- Liver converts to conjugated bilirubin –> bile
2. Too much unconjugated bilirubin in the blood –> Jaundice
What are the two reasons that jaundice can occur?
- Destruction of RBCs is happening too quickly/too much
2. Something is wrong with the liver (not converting unconjugated –> conjugated bilirubin
What happens to our RBCs if we drink too much water?
RBCs can split open
- release hemoglobin into the blood
- RBC membranes cannot tolerate excess pressure
What is hemoglobinemia?
Hemoblogin in the blood plamsa (instead of inside the RBC)
What is hemoglobinuria?
Hemoglobin in the urine (instead of inside the RBC)
What happens to blood plasma and urine when RBCs are broken down OUTSIDE of the spleen?
- Plasma turns red
- Urine turns cola-coloured
How can you impose hypoxemia?
Blood loss or going up in altitude
What stimulates the production of new RBCs?
Kidneys release erythropoietin if they sense inadequate oxygen in the bloodstream
- stimulates red bone marrow to create new RBCs
- Process takes 3-4 days
How can athletes improve their performance?
- Train at a high altitude
- Remove some blood 2 weeks prior to competition. Store blood and replace it right beforehand. This would increase the number of RBCs in circulation (increasing your oxygen carrying capacity
What are the three stimuli for erythropoiesis?
- Low level of atmospheric oxygen (high altitude)
- Increase exercise (increases consumption of O2, therefore, stimulating the creation of more RBCs)
- Hemorrhaging - decreases available RBCs, therefore, RBC production is stimulated
How is blood type determined?
Presence or absence of A and B antigens (agglutinogens) on RBC membranes
What appear in blood plasma that is related to blood typing?
Antibodies (aggultinins)
Describe the properties of Type A blood.
- Surface antigen A (on RBC)
- Anti-B antibodies (in plasma)
Describe the properties of Type B blood
- Surface antigen B (on RBC)
- Anti-A antibodies (in plasma)
Describe the properties of Type AB blood.
- Surface antigen A and B (on RBC)
- NO antibodies in plasma
Describe the properties of Type O blood.
- NO surface antigens
- Anti-A and Anti-B antibodies in plasma
Which blood type is the universal donor?
Type O
- because it does not have any surface antigens
- plasma can be spun to remove antibodies
Which blood type is the universal recipient? Why?
Type AB
- because there are NO antibodies in the plasma
- It will not react with ANY surface antigens on RBCs
Which blood type is the universal PLASMA donor?
Type AB
- because there are NO antibodies in the plamsa
Which blood type is the universal PLASMA recipient?
Type O
- because there are no surface antigens in the RBC that will interact with the plasma antibodies
What is the Rh factor?
Agglutinogens present on RBCs
Rh+ = rhesus antigen is present
Rh- = rhesus antigen is absent
If the patient is Rh-, who can they receive blood from? What if the patient is Rh+?
Rh- = can receive blood from ONLY Rh- Rh+ = can receive blood from (-) and (+)
During which pregnancy is there a risk for hemolytic disease?
Second, third, fourth, etc pregnancies
- not in the first!
When does hemolytic disease occur? Who is (+), who is (-)?
Father is Rh+
Mother is Rh-
Baby is Rh+
When does fetal blood and maternal blood mix?
During birthing
- some fetal blood will be forced into the maternal circulation due to the force of the birthing process
- the mother’s immune system will produce ANTI-RHESUS Antibodies
- mother will now attack any future Rh+ babies
How can you prevents a miscarriage for hemolytic disease in subsequent pregnancies?
Mother receives injections of RHOGAM during the course of the FIRST pregnancy
What is Rhogam?
A drug that suppresses the production of Anti-Rhesus antibodies by the mother
- if the mother does not produce the anti-bodies then she cannot attack a subsequent pregnancy
What is another name for hemolytic disease of the newborn?
Erythroblastosis Fetalis
What is the function of white blood cells? What is the name for WBCs?
Leukocytes
- defends the body against pathogens
- remove toxins, wastes, abnormal or damaged cells
Which WBCs will be found in the highest concentration? Lowest?
Neutrophils (50-70%) Lymphocytes (20-30%) Monocytes (2-8%) Eosinophils (2-4%) Basophils (
What is the function of neutrophils?
Neutrophils = highly mobile phagocytes
- present if there is inflammation or infection
What is the function of eosinophils?
Attracted to foreign compounds (allergens)
- present in allergic reactions!
When will you find basophils present?
When there is inflammation AS WELL AS an allergic reaction
an allergic reaction that is causing inflammation
When do lymphocytes increase in number?
Increase in number during infection or when a tumor is present (generally)
When will you find monocytes present?
During chronic inflammation
What is the difference between monocytes and macrophages?
Monocytes = in the blood vessel
Macrophages = in the tissues
(monocytes morph into macrophages)
What is the function of platelets?
- secrete clotting factors
- secrete vasoconstrictors in broken vessels
- form temporary platelet plugs
- dissolve old blood clots
- attract WBCs to sites of inflammation
- phagocytize bacteria
How many platelets are found in a micro-litre of blood?
130,000 - 400,000
What happens if there are too many/too few platelets in the blood?
Too many = blood clotting
Too few = bleeding
What are the three stages of hemostasis?
that platelets are involved in
- Vascular spasm (trying to close the blood vessel)
- Platelet plug formation (platelets become sticky, and stick together)
- Blood clotting (repair blood vessel wall and clotting factors)
How does the platelet plug formation occur?
Platelets stick to damaged blood vessel
What are the two different pathways that coagulation can occur?
- Extrinsic pathway
2. Intrinsic pathway
What triggers the extrinsic pathway?
Tissue damage
- Tissue factor III is released by damaged cells
What triggers the intrinsic pathway?
Collagen exposure
- Activated proenzymes (usually Factor XII) is released
What are the steps involved in the common pathway?
- Factor X (10)
- Prothrombinase breaks down prothrombin –> thrombin
- Thrombin converts fibrinogen into fibrin
- Fibrin forms strings and the strings plug the hole …
What happens if a patient does not have clotting factor VIII (8)?
Hemophilia A
What is hemopoiesis?
Blood cell formation
What is the name of the cell that divides to form all types of blood cells?
Hemocytoblasts
What are the names of the two daughter cells that hemocytoblasts give rise to?
- Myeloid stem cells
2. Lymphoid stem cells
What develop from myeloid stem cells?
- Erythocytes
- Platelets
- Basophils
- Eosinophils
- Neutrophils
- Monocytes
What develop from lymphoid stem cells
Lymphocytes
Where do myeloid adn lymphoid stem cells develop?
Myeloid = in the red bone marrow
Lymphoid stem cells = develop in peripheral lymphoid tissue
What are some examples of peripheral lymphoid tissue where lymphocytes might develop?
- Lymph nodes
- Thymus
- Spleen
- Tonsils
- Peyer’s patches (in GI tract)
What is the stimulating hormone for erythropoiesis?
EPO = erythropoietin
production of red blood cells
What happens if there is decreased blood oxygen levels?
- Kidneys secrete erythropoietin
- Bone marrow is stimulated
- New red blood cells are created
What organ secretes EPO?
Kidneys
At which stage in development of the RBC, is hemoglobin synthesized?
In the erythroblast stage
Why can hemoglobin NOT be formed in the reticulocyte stage?
The nucleus and other organelles have been ejected from the cells
What does it mean if the reticulocyte count is high?
RBCs are being produced very quickly
Why do reticulocytes have low oxygen carrying capacity?
Do not have the normal shape of RBCs
What is leukopoiesis?
Formation of white blood cells
What is thrombopoiesis?
Platelet production
TPO - stimulates the production of platelets from liver and kidneys
What happens if a patient has a very large spleen (SPLENOMEGALY)?
- Storage capacity of platelets is increased
- ability to destroy RBCs and platelets also increases
- would need to monitor platelet and RBC count
- at high risk for bleeding and anemia disorders
What is the normal range of hematocrit?
Men = 39-50% Women = 35-45%
What are some complications if a patient has a very high hematocrit?
- blood clotting
- inadequate tissue perfusion (blood is too thick)
- DVT or PE
- Higher oxygen carrying capacity
- Increased bilirubin load (risk of jaundice)
- increase work load of cardio system
What does hematocrit measure? What does hemoglobin measure?
Hematocrit = # of RBCs in circulation Hemoglobin = oxygen carrying capacity
A patient who had renal failure developed severe anemia. Why did this happen? How to correct it?
The kidneys produce EPO. EPO promotes the producetion of RBCs in bone marrow. If the kidneys are damaged, they won’t produce EPO and therefore, RBCs production will suffer.
Need to inject with EPO.
What does CM-CSF do?
Granulocyte-monocyte colony-stimulating factor
- stimulates production of basophil, eosinophil, neurtophil and monocytes
