Erythrocytes Flashcards
what percentage does plasma make up of blood?
55%
what are the components of blood with percent makeup
- 91-92% water
- 1-2% electrolytes (Na, Ca, K, HCO3)
- 7-8% protein
what is serum
plasma-clotting factors
what are the functions of blood
- transports nutrients, O2, Co2, waste products and hormones
- thermoregulation and homeostasis
what is the average blood volume in adults
5 liters
what are the plasma proteins
albumin, globulins, and fibrinogens
where are albumins made and what is their function
made in the liver
-function as transport proteins for insoluble materials (fats) and are responsible for maintaining colloid osmotic pressure in blood vessels
what are globulins used for
transport proteins for lipids and heavy metal ions
what is the largest fraction of globulins and what are they synthesized by
immunoglobulins- Ab’s synthesized by plasma cells
where are fibrinogens synthesized and what is their function
made by the liver
-function to polymerize to form insoluble fibrin during clotting (prothrombin -> thrombin catalyzes fibrinogen -> fibrin)
where does hemopoiesis occur
bone marrow of certain bones
- especially flat bones of skull, ribs, sternum, vertebrae, pelvis and some long bones
what does hemopoiesis form
RBCs, WBCs, platelets
what is hematocrit and the levels in males and females
volume of RBCs
males - 45%
females - 42%
what is polycythemia vera and what are the symptoms in females and males (blood test wise)
a type of blood cancer that causes the body to produce too many RBCs
- males have greater than 52%
- females have greater than 48%
what is PCV (packed cell volume)
basically hematocrit sometimes includes buffy coat
what is the buffy coat and how much does it make up of the blood
WBCs and platelets (about 1-2%)
what is a blood smear
drop of blood smeared, air dried, stained with modified Romanovsky method
what happens in homopoiesis
a process by which mature blood cells develop from precursor cells
what is erythropoiesis
red blood cell production
what is myeolpoiesis
white blood cell production
what enzyme control hemopoiesis and where is it secreted by
erythropoietin secreted by the kidney
what cell type does hemopoiesis begin with and differentiate into
begins with pluripotential stem cells that differentiate into several unipotential stem cell lines
how many RBCs does hemopoiesis put out daily
2.5 billion
where does hemopoiesis first occur in fetus in first trimester
blood islands in wall of yolk sac
where does hemopoiesis occur in fetus in second trimester
liver and lymphatic tissue
where does hemopoiesis occur in fetus in last month of pregnancy
bone marrow
what type of bone marrow is active in blood cell production
red marrow
what type of marrow is inactive
yellow or fatty marrow
what are the stages of erythropoiesis
stem cell (CFU-E) -> proerythroblast->erythroblast/normoblast -> reticulocyte -> mature RBC
what are some visual trends during erythropoiesis
decrease in cell size, loss of nucleus and organelles, increase in concentration of hemoglobin
why do cells appear darker in the beginning of erythropoiesis
because they still have nuclei
during what stage does decreased cell size and loss of nucleus occur in erythropoiesis
normoblast
how do RBCs make energy
glycolysis because they only have a cytoplasm
what removes old RBCs
liver and spleen
what are howell-jolly bodies in erythropoiesis
occasional, basophilic nuclear remnants visible in cytoplasm
what are reticulocytes
immature RBCs with stippled cytoplasm, still have some rRNA
how do you identify reticulocytes
faint, small, blue/purple spots
what is reticulocytosis
increased reticulocytes in circulation
when would we see reticulocytosis
chronic blood loss, hemolytic anemia, infections
where would we see macrocytes
Vit B12 and B9 deficiencies
how do you identify megaloblastic anemia in a slide
large numbers of erythrocyte stem cells in blood
what happens to the hematocrit in reticulocytosis
it is lower than normal
how big are erythrocytes
6-8 micrometers
what is the primary structural protein in RBCs
spectrin
what is the function of spectrin
provides resiliency and deformability
where does spectrin bind
inner surface of plasma membrane
what is a benefit of the bioconcave shape of red blood cells
increased SA for gas exchange
describe the structure of hemoglobin (Hb)
4 polypeptide chains associated with 4 Fe containing heme groups
how would you describe iron deficiency anemia based on stain appearance
microcytic and hypochromic
what does microcytic describe
small RBCs
what is sickle cell anemia caused by (genetically)
a substitution of valine for glutamic acid at position 6 of beta globulin chain
what is malaria caused by
intracellular blood parasite, plasmodium spp
describe what platelets are
small, non nucleated cells containing organelles
- “cell fragments”
what are platelets formed from
large, polyploid cells in bone marrow called megakaryocytes
describe the appearance of megakaryocytes on a slide
singel, multi lobed nucleus
what are demarcation channels
happens when platelets “tear off”
whats the lifespan of platelets
8-12 days
what is the function of platelets
blood clotting
when does coagulation occur
if endothelial lining of vessel in injured
describe the extrinsic pathway in coagulation
initiated by the release of tissue thromboplastin as a result of tissue damage
describe the intrinsic pathway of coagulation
initiated by exposure of collagen and requires numerous clotting factors
which pathway is faster in coagulation
extrinsic
describe the pathway in coagulation
- release of thromboplastin initiates extrinsic pathway. this exposes collagen which initiates the intrinsic pathway. platelets adhere to collagen and release serotonin.
- pathways converge to form common pathway that converges prothrombin to thrombin and converts soluble fibrinogen to insoluble fibrin
what stops clotting
exhaustion of fibrinogen and removal of thrombin from blood during converion of fibrinogen to fibrin
what are some anticoagulant medications
antithrombin III and heparin
what is hemophilia
deficiency in clotting factors so blot cant clot (defect in intrinsic pathway)
- sex linked in males
what is hemophilia A
deficiency of clotting factor VIII
what is hemophilia B
factor IX deficiency
what is hemophilia C
factor XI deficieny
