Chapter 19: Blood Flashcards
Albumins
smallest and most numerous plasma protein
maintain osmotic pressure - important in exchange of fluids across blood capillaries
Globulins (alpha, beta, gamma)
large proteins, develop B lymphocytes which help attack viruses and bacteria
alpha and beta: transport iron, lipids, and fat sol. vits
gamma: called antibodies or immunoglobins
3 major blood plasma proteins
albumin, globulin, fibrogen
Fibrogens
blood clotting
What are the formed elements in blood?
RBC, WBC, platelets
45%
Hematocrit
percentage of total blood volume that is occupied by RBC
Order of importance of WBC
Neutrophils Lymphocytes Monocytes (become macrophages) Eosinophils Basophils
What are platelets formed from and what’s another name?
broken down megakariocytes;
thrombocytes
What is the order of centrifuged blood from top to bottom and what percentage?
TOP: plasma (55%)
MIDDLE: Buffy coat (WBC/platelets)
BOTTOM: RBC (45%)
Explain some characteristics of neutrophils
nucleus contains 2-5 lobes connected by chromatin
phagocytosis
contains Barr bodies
first line of defense
spherical when inactive, but change shape when activated
Explain some characteristics of lymphocytes (include the three big types)
vary in size, but the larger in size the more visible the cytoplasm; important roles in immune response including antigen-antibody reactions
B CELLS=develop into plasma cells which secrete antibodies
T CELLS=attack invading viruses, cancer cells, transplanted tissue cells
NK CELLS=attack wide variety of infectious microbes and spontaneous tumor cells
Explain some characteristics of monocytes
largest WBC with a horseshoe-shaped nucleus
no direct function in plasma, but once emigrated they transform into macrophages
Explain some characteristics of eosinophils
nucleus contains 2 lobes connected by chromatin
only in blood 3-4 hours then tissue 10 days
increase in number during parasitic invasion and allergic reactions - combat effects of histamine
phagocytize antigen-antibody complexes
clot dissociation
Explain some characteristics of basophils
nucleus has 2 lobes which are twisted into an “S” shape
largest granules, but least abundent
liberates heparin, histamine, and serotonin in allergic reactions that intensify overall inflammatory response
What are the components of hemoglobin & describe them
globin: chain of 4 polypeptides (2 alpha, 2 beta)
heme: nonprotein cofactor with an iron containing ring (porphyrin) which allows 4 oxygen molecules to attach
Also binds CO2 and NO (vasodilator so regulates blood flow and blood pressure)
How do RBCs produce energy?
Do not contain mitochondria so use aerobic respiration
What happens to damaged/dying RBC’s?
phagocytized by macrophages in the spleen (also in red bone marrow and liver) breaking it into globin and heme portions
rate of formation = rate of destruction
Trace the pathway of the iron group from heme break down.
- Fe2+
- Fe3+
- Fe3+–transferrin (leave spleen)
- ferritin storage (in liver)
- Fe3+–transferrin to the red bone marrow
- erythropoiesis in red bone marrow;
[Fe3+, B12, globin, amino acids, EPO (erythropoietin)] to form new RBC - RBC into circulation
Trace the pathway of the non-iron group from heme break down.
- biliverden (green color)
- bilirubin (yellow color) leaves spleen
- bilirubin enters liver
- enter small intestine via bile
- with bacteria forms urobilinogen
- breaks into urobilin (to kidney to be excreted in urine;yellow) and stercobilin (feces; brown color)
What are the steps of erythropoiesis beginning with the pluripotent stem cell?
Hemocytoblast (pluripotent stem cell) > myeloid stem cell > proerythroblast > nucleus ejected > formation of reiculocyte (contains some organelles) > released into blood > organelles ejected > (1-2 days; organelles ejected) > RBC (erythrocyte)
Procrit and Epogen
used to help increase RBC production
How do cancer patients often get anemia and fatigue?
Tumor cells are rapidly growing so they absorb blood more quickly which would contain toxins (chemotherapy), but this would also affect the RBC (and hair loss)
What are the three ways athletes blood dope? What is a major risk?
- increase erythropoietin
- remove RBC and then re-inject later
- practice at high altitudes
Increase in RBC and increase the viscosity of the blood
Two forms of stem cell transplants:
- Bone marrow transplant from a matching donor; takes 2-3 weeks to attach and placed on immunosuppressin drugs to avoid rejection
- cord-blood transplant from stem cells in an umbilical cord - these cells are much younger and more fusible
What is hemostasis? What are the three mechanisms?
a sequence of responses that stops bleeding to prevent hemorrhaging (large amounts of bleeding)
- Vascular spasm
- Platelet plug formation
- Blood clotting
Three steps in vascular spasm:
- Smooth muscle damage
- When damage has occurred, endothelial and platelets release substances causing contraction
- Reflex initiated by pain receptors to prevent blood loss
What are platelets formed from?
broken down megakaryocytes (small but carry many substances)
Relationship between platelets and endothelial/smooth muscle
platelets don’t adhere to endo/SM because endo secretes nitric oxide and prostacyclin which prevent platelet aggrigation by opposing thomboxane A2
Three steps in platelet plug formation:
- Platelet Adhesion: platelets bind to damaged/exposed collagen fibers
- Platelet release Action: platelets release ADP, serotonin, and thromboxane A2 (S&T are vasoconstrictors ~ enhances vascular spasm)
- Platelet Aggregation: the release of ADP causes platelets to become sticky and form a platelet plug mass
Von Willebrand factor:
made by endothelial cells and helps join plugs together and stabilize the area
thromboplastin
tissue factor in extrinsic pathway made up of lipoproteins and phospholipids
steps of extrinsic pathway
- tissue trauma
- tissue factor (thromboplastin) enters from outside the blood
- TF combines with calcium to form activated Factor X
- Factor X combines with calcium and Factor V to form prothrombinase
- prothombinase converts prothrombin to thrombin with calcium
- thrombin converts fibrinogen (soluble) to loose fibrin (insoluble); thrombin also activates Factor XIII
- Factor XIII strengthens the loose fibrin molecules (crosslinking enzyme)
steps of intrinsic pathway
- blood trauma
- activated Factor XII with calcium forms activated Factor X
- Factor X along with calcium, factor V, and platelet phospholipids activate prothrombinase
- prothrombinase cleaves prothrombin into thrombin
- thrombin converts fibrinogen to loose fibrin and activates Factor XIII
- loose fibrin is converted to tightened fibrin by Factor XIII
Difference between extrinsic and intrinsic pathway?
Extrinsic: happens within seconds; due to tissue damage
Intrinsic: happens within minutes; due to endothelial damage; includes factor XII
