Hematology Physio Flashcards
What are the components of blood
- plasma (55%)
- formed elements (erythrocytes (45%), leukocytes, platelets (1%))
What is the normal pH range of our blood
7.35-7.45
What is the average blood volume of adult males and females
Male: 5-6L
Female: 4-5L
Describe the functions of blood
- Distribution (O2, nutrients, waste, hormones)
- Regulation (temp, pH, fluid)
- Protection (blood loss, infection)
What are the components of plasma
- 90% water
- proteins mostly produced by the liver (albumin, globulin, fibrinogen)
- clotting factors
- hormones
- respiratory gases & electrolytes
- nutrients
What is the normal albumin-globulin ration
4:2
Does serum contain clotting factors?
No, clotting factors are found only in plasma
What cell gives rise to all formed elements of our blood?
Multipotential hematopoietic stem cell (hemocytoblast)
What are the two types of cells that differentiate from hemocytoblasts
common myeloid progenitor
common lymphoid progenitor
(these branch farther into many cells, leukemias will affect one line or the other)
Define erythrocytes
- biconcave discs
- anucleate
- no organelles (anaerobic ATP production)
- contains spectrin
What is the purpose of spectrin in erythrocyte plasma membranes
provides flexibility to change shape as needed
(deficiency leads to a type of anemia)
Describe the structure of hemoglobin
- protein globin: 2 alpha & 2 beta chains (adults, 2 gamma in fetal)
- heme pigment bonded to globin
- iron atom in each heme (can bind 4 O2)
What is a reticulocyte
a mature form of a red blood cell that is not yet an erythrocyte
(formed during erythropoiesis after nucleus is ejected)
Where does erythropoiesis occur
red bone marrow
What is a scenario in which reticulocyte count would be low
aplastic anemia
What regulates erythropoiesis
Hormones
- erythropoietin
- testosterone
Nutrients
- amino acids, lipids, carbs
- iron
- vit B12
What is iron stored in the cells as and what is it transferred by
Storage: ferritin & hemosiderin
Transport: transferrin
What is the lifespan of a RBC
100-120 days
(then destroyed by macrophages in the spleen)
(Hgb A1C measures this)
What happens after a RBC is broken down
- iron salvaged for reuse
- heme degraded to yellow pigment unconjugated bilirubin, which gets conjugated in the liver, excreted as stercobilin & urobilinogen
- globin metabolized into amino acids
Define anemia
- blood has abnormally low O2 carrying capacity
- sign, not disease
- fatigue, pallor, SOB, chills
What kinds of anemia are caused by insufficient erythrocytes
- hemorrhagic
- hemolytic (RBCs destroyed)
- aplastic (Bone marrow destroyed)
What kinds of anemia are caused by low Hgb
- iron deficiency (secondary to hemorrhage, impaired iron absorption
- pernicious (Vit B12 deficiency, lack of intrinsic factor for absorption)
What kinds of anemia are caused by abnormal Hgb
- thalassemia (absent/faulty globin, think delicate RBC)
- sickle cell (gene code, low in oxygen)
When does sickling happen in sickle cell anemia
When oxygen dissociates from the heme (especially during high O2 demand like exercise)
Define polycythemia
excess of RBCs that increase blood viscosity
- bone marrow cancer, O2 loss, blood doping
What process allows WBC to leave capillaries
diapedesis
What makes up granulocytes & agranulocytes
Granulocytes
- neutrophils (50-70%)
- eosinophils (2-4%
- basophils (1%)
Agranulocytes
- lymphocytes (25-45%)
- monocytes (3-8%)
Which WBCs will stain with Wright’s stain
granulocytes (neutrophils, eosinophils, basophils)
- larger, shorter lived
- lobed nuclei
- phagocytic
Which WBC has granules that contain hydrolytic enzymes or defensins
Neutrophils (bacteria slayers)
Which WBC digests parasitic worms & modulates immune response
eosinophils
Which WBC contains histamine & functions similarly to mast cells
basophils
Describe the 2 types of lymphocytes
- T cells: act against virus-infected cells & tumor cells
- B cells: give rise to plasma cells that produce antibodies
What is the largest WBC and what does it do
monocytes
- differentiates into macrophages
- activates lymphocytes for immune response
What chemical messengers from bone marrow & mature WBCs stimulate leukopoiesis
interleukins & colony-stimulating factors
Describe platelets
- anucleate cell fragments
- formation regulated by thrombopoietin (hormone from liver & kidneys)
What are in the granules of platelets & why are these important
- Ca, enzymes, ADP, phospholipids, platelet derived growth factor, serotonin
- important in hemostasis
What does the platelet membrane consist of
- lipid bilayer
- glycoprotein receptors (important in hemostasis)
What are the functions of platelets
- form temporary plugs that seal breaks in blood vessels
- circulating when inactive and made mobile by nitric oxide & prostacyclin from endothelial vessel lining
Describe the phases of hemostasis
- primary (vascular spasm & platelet plug)
- secondary (coagulation)
- stoppage of hemostasis (proteins)
- fibrinolysis (clot dissolves)
Describe the steps of platelet plug formation (step 2 of hemostasis)
- adhesion via vWB factor
- aggregation via ADP
- secretion of granular contents
Describe coagulation (step 3 of hemostasis)
- reactions in which blood is transformed from liquid to gel
- reinforces platelet plug with fibrin threads
- requires coag/clotting factors, Ca, phospholipids
Describe the 3 phases of coagulation
- prothrombin activator formed
- prothrombin converted to thrombin
- thrombin catalyzes fibrinogen to form fibrin mesh
Which clotting factors require vitamin K
Factors II, VII, IX, and X
What is the major difference between the intrinsic pathway and extrinsic pathway of clotting
Intrinsic: direct to blood vessel injury
Extrinsic: tissue cell trauma prior to blood vessel response
What forms all clotting factors
the liver
(all circulate in blood in an inactive form)
What is the main end product of phase 1 of coagulation
formation of prothrombin activator (activates prothrombin to thrombin in phase 2)
What is the main end product of phase 3 of coagulation
fibrin mesh
Describe clot retraction
- actin & myosin in platelets contract within 30-60 mins which squeezes serum from the clot
Describe clot repair
- PDGF stimulates division of smooth muscle cells & fibroblasts to rebuild vessel
- VEGF stimulates endothelial cells to restore lining
Which proteins inactivate activated clotting factors
- antithrombin III
- protein C
- heparin
What things prevent platelet adhesion
- nitric oxide, prostacyclin (from endothelial lining)
- vit E, quinine (anticoags)
Describe fibrinolysis
- begins within 2 days
- plasminogen converted to plasmin by tPA, factor XII, thrombin
Describe disseminated intravascular coagulation (DIC)
- widespread clotting blocking intact blood vessels
- can cause severe bleeding
- common in pregnancy, septicemia, incompatible transfusion
- prevention: ASA, heparin, warfarin
Describe thrombocytopenia
- deficiency of platelets
- petechiae d/t spontaneous widespread hemorrhage
- tx with transfusion of concentrated platelets
Describe the types of hemophilia
- A: most common, deficiency of factor VIII
- B: deficiency of factor IX
- mild, deficiency of factor XI
- prolonged bleeding (into joints)
Which blood groups can cause vigorous transfusion reactions
ABO & Rh
Which blood group is a universal recipient
AB
Which blood group is a universal donor
O
Which blood group can receive blood from B or O
B (has anti-A antibody)
Which blood group can receive blood from A or O
A (has anti-B antibody)
Which blood group can receive blood from only group O
O (has anti-A and anti-B antibodies)
Which blood group can receive blood from A, B, AB, or O
AB (no antibodies)
When do Rh antibodies form
- if an Rh negative person receives Rh+ blood
- NOT spontaneous
Describe hemolytic disease of the newborn (erythroblastosis fetalis)
anti-Rh antibodies cross placenta and destroy RBCs of an Rh+ baby after Rh- mom becomes sensitized to Rh+ exposure & produces anti-Rh antibodies
What happens in a transfusion reaction
- occurs in mismatched infusions
- donors cells are attacked by recipients agglutinins, clog small vessels, rupture & release Hgb
- diminished O2 capacity, renal failure
