summer hem Unit 1

cell morphology/appearance is based on

wright-giemsa stain

peripheral smear

tool for evaluating hematologic disorders, must have proper length width thickness and feathered edge

wright-giemsa

romanosky type stain with acidic eosin Y and basic azure B dyes (pH dependent)

acidic structures

azure B basic dye, basophillic, blue-purple, rna in cytoplasm, basophil granules

basic structures

eosin Y staining pink-red-orange, hemoglobin in rbcs, eosinophil granules

neutral structures

pinkish-purple-tan, neutrophil granules

blood composition

total volume 4-6 L

55% plasma

45% cellular elements (1% wbc and plt= buffy coat, 44% rbc

wbcs

lymph, mono, granulo (neut baso eosin)

erythrocyte

rbc, 6-8um, transports O2, millions of them, live for abt 4 months

leukocyte

wbc, 6-18 um, defend, hundreds or thousands of them, live for days to years

thrombocyte

platelets plt, 2-4 um, clot blood, thousands of them, live for 10 days

hematopoiesis

continuous process of producing, developing, and replacing all blood cells from hsc

hematopoietic system generation

yolk sac + AGM 2-4 weeks

hematopoietic system maturation and expansion

liver 2-7 months

hematopoietic system life-long

bone marrow, forever after

myeloid precursors for

granulocytes, monocytes, erythro, and megakaryocytes

lymphoid precursors for

b t nk

totipotent

can make every cell and placenta

pluripotent

can make every cell

multipotent

can make all cells of a specific lineage

embryonic hematopoiesis extraembryonic

2-3 weeks, blood islands in yolk sac, erytho and embryonic hgb carry O2, macro phag, megakar produce plt

embryonic hematopoiesis intraembryonic

4 weeks, aorta-gonads-mesonephros AGM region, first HSC producing every type of blood cell

fetal hematopoiesis liver

3 months, elevated erythroid and hgb F (fetal hgb), begin myeloid and lymphoid

fetal hematopoiesis spleen, kidney, thymus, lymph nodes

eventually move to BM, produce wbc and plt first then rbc

thymus

fetal t cell production, active through childhood

lymph nodes and spleen

b cell differentiation throughout life, secondary lymph tissue, further differentiation in response to antigens

adult hematopoiesis

BM- myeloid erithroid megak development, early stages of lymph cell development, provides microenvironment with growth factors and cytokines

thymus spleen lymph nodes- lymphocyte maturation and activation

regulation factors

EPO- erythropoietin, elevated erythrocyte production

TPO- thrombopoietin, elevated platelet production

CSFs- colony stim factor, elevated leuk production

cell maturation

bm contains precursor cells throughout development, blast (1st morphologically recognizable precursor), predictable nuclear and cytoplasmic changes during maturation

normal conditions in cell maturation

only mature blood cells released into circulation

blasts or immature cells

increasing cell size and nucleus, fine chromatin, nucleoli present, basophilic cytoplasm

maturing cells visual

decreasing cell size and nucleus compared to cytoplasm, condensed or clumped chromatin, nucleoli disappear, cytoplasm increases

bm cellularity general

% of bm occupied by hematopoietic cells, decreases with age as fat replaces marrow, red= active, yellow= fat

In a 70-year-old patient, where would a clinician expect to find the most active red marrow?

Axial skeleton, such as the pelvis or sternum

hypercellular

more than 70% cellularity, leukemia, looks all purple

normocellular

30-50% cellularity

hypocellular

less than 30% cellularity, aplastic anemia, all gray

myeloid :erythroid ratio M:E

assessed as part of BM testing, 3:1-4:1, neutrophils regenerate more frequently making more of them in ratio

medullary hematopoiesis

in bm, can increase activity 7-8x if needed, hypercellular

extramedullary hematopoiesis

in tissue other than bm, liver and spleen factories reopen when bm cannot keep up, predominately makes hgb F, organs may enlarge (hepatosplenomegaly)

HSC self- renewing cells break into

CMP (myeloid progenitor) or CLP (lymph)

CLP becomes

lymphoblast > prolymphocytes > nk b or t thymus mature then blood > plasma cells in tissue

CMP becomes

megakaryoblast, proerythroblast, myloblast, monoblast

CMP > megakaryoblast become

promegakayocyte > megakarocyte > thrombocytes plts

CMP > proerythroblast (pronormoblast, rubiblast) become

basophilic normoblast or prorub > polychromatic normoblast or rubi > orthochomatic normoblast or metarub, reticulocyte > rbcs

CMP > myeloblast > (use b. n. or e. in front of all for basophil neturophil or eosinophil)

b. promyelocyte> b. myelocute > meyamyelocyte > band > basophil neutrophil eosinophil

CMP > monoblast >

promonocyte > monocyte > macrophage

erythropoisis

production of rbcs, 1% of circulation rbcs are replaced daily, regulated by tissue O2 delivery

erythropoetin EPO

gycoprotein, primary regulatory erythropoiesis, response in 5 days, prevents apoptosis of precursors, hypoxi causes increased renal release of EPO

erythroblastic islands

erythroblast develop surounding a central macrophage that supplies iron cytokines and remove extruded nuclei

predicting rbc maturation

decreasing size, chromatin condensation, decreasing N:C nucleur extrusion, decrease rna and ribosomes (deep blue becomes pink cytoplasm), elevated hgb

maturation in bm- pronormoblast proerythroblast rubriblast

earliest recognizable precursor, deep basophilic cytoplasm, nucleoli (site of ribosome production)

maturation in bm- basophilic normoblast baso erythroblast prorubricyte

deep blue cytoplasm, rna rich

maturation in bm- polychromatophilic normoblast

last stage capable of mitosis, more pink cytoplasm, octer ring

maturation in bm- orthochromic normoblast erythroblast metarubricyte

pinking cytoplasm, pyknotic nucleus (skrunken condensed), nucRBC on peripheral smear

maturation in peripheral blood- reticulocyte retic

moves from bm to circulation, residual rna, last stage capable of hgb synthesis, retic count indicated bm response due to being newly released in bm

reticulocyte retic wright-giemsa stain

purple cytoplasm= poly, suggests presence of retic must do meth/crystal blue stain or further test

reticulocyte retic reticulocyte stain

supravital stain of living cells, new methylene blue or brilliant crystal blue, residual rna precipitates, blue granules or reticulum

mature rbcs

no nuc mitochondria or rib, carry O2 from lungs to tissues and CO2 back to lungs, biconcave disc, flexible deformable, senescent cells destroyed by macrophages in spleen (liver and bm)

mature rbcs visualize

wright-giemsa stain, orange-pink, central pallor is 1/3 of the diameter, normocytic- 7 um same as the nucleus of small lymph, normochromic- normal hgb content with central pallor

nucleated percursors

5-7 days in bone marrow

reticulocytes lifespan

1-2 days in bone marrow, 1-2 days circulation

erythrocyte timeline

120 days, circulation

hemoglobin hgb Hb

major oxygen-carrying protein of rbc and 20-25% of CO2, H+ buffer, 95% of rbc dry weight = millions per rbc, synthesized during erythropoiesis

synthesis of hgb compisition

75-80% made before the nucleus in extruded, 20-25% made by residual rna/mitochondria in retics

hgb concentration =

balance of rbc production/destruction, ref range 12-18 g/dL, male- 14-18 female- 12-15

hgb synthesis requires

iron delivery and supply, synthesis of protoporphyrin IX (heme precursor), and globin synthesis

iron

total body- abt 4g, mainly in hg, recycled by macrophages, incorporated into heme during erthropoiesis, transferrin- transport protein, myoglobin- local O2 storage

hgb size

molecular weight- 66.7 kDa

hgb structure

4 globular protein subunits, 2 globin chains, heme in hydrophobic pocket, iron reversibly binds 1 O2

1 hgb =

4 O2 molecules

alpha like vs non alpha chains

alpha and zeta embryonic vs epsilon embryonic, beta, delta, gamma

heme

protoporphyrin IX (tetrapyrrole) ring, central ferrous Fe2, iron-1 O2, inserted in hydrophobic pocket near exterior surface of each subunit

type of iron that can bind O2

ferrous Fe2

oxyhemoglobin vs deoxyhemoglobin

O2 bound vs O2 released

HbA

20% at birth, a2b2, more than 95% in life

HbA2

0% at birth, a2delta2, less than 3.5 % in life

HbF

80% at birth, a2Y2, less than 1% in life

partial pressure of O2 PO2 or PaO2

amount of dissolved O2 available in plasma, increased PO2= more O2 availible to bind to hgb, low PO2= less O2 available so hgb releases O2, O2 tension

hgb saturation O2 sat

percent of hgb binding sites occupied by O2, dependent on PO2, arterial SaO2 measured with ABG, peripheral SpO2 measured with pulse oximeter using red and IR light

O2 affinity

tendency to bind O2, high= tightly bound, low= releases O2 more readily, changes facilitate loading and unloading

hgb binding

positive cooperativity, first O2 binding changed hgb shape increasing affinity for next O2, release of 1 O2 deceases affinity promoting additional release

P 50

PO2 when hgb is 50% saturated y axis, indicator of oxygen affinity

fetal hgb

a2Y2, higher afinity for O2 causing saturation at lower PO2, facilitates maternal fetal O2 transfer, declines after birth

CO2 transport

mainly as bicarbonate in plasma, abt 20% carbaminohemoglobin HbCO2 in rbcs, move to lungs for exhalation

carbaminohemoglobin HbCO2

abt 20% of CO2 diffusing into rbcs and binding to hgb globin chains

abnormal hgb- methemoglobin metHgb metHb

iron oxidized Fe2>3 ferric, increased deoxyhemoglobin causing chocolate-brown blood, reversed with methylene blue treatment, toxic levels cause cyanosis hypoxia

abnormal hgb- carboxyhemoglobin COHgb COHb

CO binds instead of O2, CO has over 200x the affinity than O2, increases O2 affinity at remaining sites, impaired O2 unloading= tissue hypoxia, cherry red blood, treated with O2 therapy, left shift on graph