Hematopoiesis I: Blood Flashcards
hematopoiesis
formation of blood and its components (RBCs, WBCs, megakaryocytes/platelets)
hematopoietic tissues during gestation
yolk sac: 0-3 months of gestation liver: main hematopoietic organ from 2-7 months of gestation spleen: small amt. of hematopoiesis from 3-6 months of gestation bone marrow: starts hematopoiesis during 4th month, becomes primary source during 7th month of gestation
primary hematopoietic tissues in adulthood
vertebra, sternum, rib
primary hematopoietic tissues from birth till around 25 years old
tibia and femur
formed element
solid components of blood, includes RBCs, WBCs, platelets
percentages of formed blood elements
RBCs: 41-53% in males, 36-46% in females WBCs and platelets: about 1% (buffy coat)
plasma
liquid extracellular component of blood
discuss the contents of plasma (w/ percentages)
water: 90% protein: 7% (albumin, globulins-alpha, beta, gamma, fibrinogen, prothrombin) inorganic ions: 0.9% the rest is composed of nutrients, blood gases, hormones etc.
serum
clear, yellow supernatant after blood coags. like plasma but w/o clotting factors, platelets, cells. contains factors released from platelets (e.g. growth factors)
function of erythrocytes
transport O2 and CO2
lifespan of erythrocyte
~120 days
reticulocyte
immature RBC, still has some ribosomes, normally 1-2% of erythrocytes, stain blue
microcyte
erythrocytes that are too small, <6 micron, due to low iron
macrocyte
erythrocytes that are too large >9microns in diameter, due to low B12 and folic acid
morphology of erythrocytes
anucleate, lack many organelles, biconcave discs, ~7.5micron diameter, flexible
oxyhemoglobin
hemoglobin bound to O2
carboxyhemoglobin
hemoglobin bound to CO, irreversible binding, leads to CO poisoning
carbaminohemoglobin
hemoglobin bound to CO2
sickle cells
mutated hemoglobin aggregates and distorts cell shape, cells are rigid fragile, short-lived
what are the two major classes of leukocytes
- granulocytes: PMNs (polymorphonuclear) 2. agranulocytes: mononuclear
what are the three types of granulocytes?
granulocytes are one of the two classes of leukocytes. 1. neutrophil 2. eosinophil 3. basophil
what are the three types of agranulocytes?
agranulocytes are one of the two classes of leukocytes. 1. lymphocyte (become B and T cells) 2. monocyte
what is the suffix that denotes whether a cell is a granulocyte? agranulocyte?
granulocyte: -phil (because it’s FILLED w/ granules) agranulocyte: -cyte
what is the concentration and percentage of leukocytes in the blood?
4,400-11,000 leukocytes/microleter of blood ~0.1% of blood cells
what is the concentration and percentage of neutrophils?
1,800-7,700/microleter 50-70% of leukocytes
what is the concentration and percentage of lymphocytes?
1,000-4,8000/microleter 18-42% of leukocytes
function of neutrophils
first leukocytes to extravasate; phagocytose bacteria and other small particles
respiratory burst
burst of O2 consumption by neutrophils during phagocytosis- leads to formation of toxic superoxide anions and hydrogen peroxide that helps degrade bacteria in tissues
what is the purpose of lactoferrin and which leukocyte uses lactoferrin?
binds iron which is a crucial element in bacterial nutrition, released from granules present in neutrophils
what is the purpose of lysozyme?
cleaves bonds in cell wall of some gram-positive bacteria
discuss the morphology of neutrophils
has a 2-5 lobed nucleus, linked by threads of chromatin, relatively few mitochondria (allows cell to live in poorly oxygenated tissues-i.e. inflamed, necrotic), granules are difficult to see
discuss the life cycle of neutrophils
produced in the sinusoids of the bone marrow, short-lived, half-life of 6-7 hours in blood, 1-4 days in connective tissue, die by apoptosis
granule contents of neutrophils
granules contain lysozyme, lactoferrin to help degrade bacteria via phagocytosis
granule contents of eosinophils
5’nucleotidase, elastase, collagenase, myeloperoxidase, lysozyme, cationic antibacterial proteins, phospholipase, RNase, eosinophilic peroxidase
discuss the location of neutrophils in the body
circulate in the blood, extravasate when prompted by infection/inflammation
function of collagenase
degrades extracellular matrix, neutrophil and eosinophil granules release this in order to move freely through tissues
band neutrophils (percentage, origin)
2-5% of neutrophils are immature (band neutrophils), infections and leukemia may increase number of band neutrophils; originate in the bone marrow, then released in blood stream
structure of eosinophils
usually bilobed nucleus, granules stain blue, do not overlie nucleus
function of eosinophils
kill parasites and tone down immune response, phagocytize antigen-antibody complexes
granule contents of eosinophils
histaminase (anti-histamine), collagenase, cathepsin (proteinase), arylsulfatase
where are eosinophils found in the body?
connective tissue underlying epithelia of bronchi, GI, uterus, vagina (they are found in normal tissues)
what might cause an increase in eosinophils in the blood (eosinophilia) indicate?
allergic rxn, parasitic (helminthic) infections
what compounds (found in eosinophil granules) inactivate leukotrienes and histamine?
arylsulfatase and histaminase
structure of basophils
irregular, lobed nucleus, large granules that overlie nucleus, nucleus stains pink
function of basophils
nonphagocytic granulocytes; functionally similar to mast cells, promote allergic rxns, bind IgE antibodies for allergen specificity
granule contents of basophils
eosinophilic chemotactic factor, heparine, histamine, peroxidase, leukotrienes
what type of leukocyte has a horseshoe shaped nucleus when not fully developed?
neutrophil
structure of monocytes
large, oval, horseshoe, kidney shaped nucleus, less condensed chromatin, cytoplasm stains blue
function of monocytes
monocyte-derived cells (e.g. macrophages) involved in innate and adaptive immune response, bacterial phagocytosis, wound healing, bone resorption, debris removal
MPS
mononuclear phagocytic system, monocytes are precursor cells to this system (e.g. turn into macrophages, big part of MPS)
lifespan of monocytes
in blood ~3 days
lifespan of platelets
~10 days
what are the three types (an percentages) of lymphocytes
T lymphocytes (60-80%) B lymphocytes (20-30%) natural killer cells (>10%)
what is the role of T lymphocytes?
involved in cell mediate immunity, activate B cells, macrophages, cytotoxic T cells
what is the role of B lymphocytes?
involved in humoral immunity, precursors to Ab-producing plasma cells
what is the role of NK cells?
kill certain virus-infected cells and some tumor cells
percentage of eosinophils
1-3% of leukocytes
percentage of monocytes
2-8% of leukocytes
