hematopoiesis

hematopoiesis

continuous, regulated production of blood cells

mesoblastic, hepatic phase, medullary (myeloid phase)

3 phases of hemtopoiesis

renewal, proliferation, differentiation, maturation, death

processes of hematopoiesis

19th day of fetal development

when does mesoblastic phase begin

yolk sac

primitive erythroblasts

• major site of mesoblastic phase

gower -1, gower -2, porrtland Hgb

produced at the yolk sac specifically primitive erythroblasts

blood vessels

what surrounds the yolk sac

Aorta Gond Mesonephrons

meaning of AGM

Aorta Gonad Mesonephrons

produces the hematopoietic stem cells

intravascularly

mesoblastic hematopoiesis occurs _______

2 E + 2 z

gower -1

2 a + 2E

Gower -2

2 z + 2 gamma

portland

5-7 gestational weeks

begin of hepatic phase

hepatic phase

production of erythroblasts, granulocytes, monocytes, lymphoid cells, and megakaryocytes

extravascularly

hepatic phase occurs _______

mesoblastic stage

primitive hematopoiesis

hepatic and medullary stage

definitive hematopoiesis

liver

major site of hepatic stage

3rd month of fetal development

peak time of hepatic stage

6th month of fetal development

decline of hepatic stage

1-2 weeks after birth

minimal activity of hepatic stage

Hb F

predominant hemoglobin in hepatic stage

thymus

first major organ in the body

kidney & spleen

sites of b cell production

Thymus, spleen, placenta, bone marrow, kidney

other production site of hepatic phase

Fetal hemoglobin

meaning of Hb F

Adult hemoglobin

meaning of Hb A

2 a + 2 gamma

Hgb F

2 a + 2 B

Hgb A

2 a + 2 Delta

HgbA2

bone marrow

major site of medullary stage

4th and 5th month of fetal development

beginning of medullary stage

6th month

when does medullary phase become primary site

medullary phase

migration of mesenchymal cells into the core of the bone, which differentiates into cells that support developing blood cells

3:1 to 4:1

myeloid:erythroid ratio

medullary phase

presence of EPO, G-CSF & GM-CSF, HbF, HbA

kidneys

erythropoietin is produced where

RBC erythropoietin

what is produced in kidneys during medullary phasse

erythropoietin

meaning of EPO

colony stimulating factor

meaning of CSF

granulocyte macrophages colony stimulating factor

meaning of GM-CSF

bone marrow, liver, spleen, lymph node, thymus

adult hematopoietic tissues

bone marrow

one of thee largest organs in the body

bone marrow

tissue that is supported by the trabeculae

bone marrow

contains hematopoietic cells, stromal cells, and blood vessels

red bone marrow

type of bone marrow that is dominant during infancy and childhood

retrogression

conversion of red to yellow marrow during development

50% hematopoietic cells, 50% adipocytes

percent of normal bone marrow

red marrow

type of bone marrow that is hematopoietically active and contains blood cells and progenitors

yellow marrow

type of bone marrow that is hematopoietically inactive and contains adipocytes and undifferentiated mesenchymal cells

RS3VP2

remaining sites of bone marrow

yes, due to increased blood flow that can turn yellow to red marrow

can yellow marrow revert to red marrow

liver

major site of blood cell production during 2nd trimester

synthesis, storage, detoxification, conjugation, excretory

adult function of liver

kupffer cells

liver macrophages

liver macrophages

what removes senescent cells and foreign debris in the blood

porphyria and hemolytic anemia

blood diseases related to the liver

• deficiency of enzymes needed in heme biosynthesis

• red urine and tears

• sensitive to light

• known as the vampire disease

hemolytic anemia

• leads to increased bilirubin conjugation and iron storage

• infection/myelofibrosis of the bone marrow

  • leads to extramedullary hematopoiesis

spleen

largest lymphoid organ

spleen

organ that is vital but not essential

350 mL

blood amount in spleen

• stores platelets (30%)

• filters circulating blood

  • RBCs culling and pitting

functions of spleen

culling

destroying the cell as a whole

pitting

removing the imperfections

spleen

known as RBC graveyard

splenomegaly

enlarged spleen

• chronic leukemia

• inherited membrane or enzyme defects in RBCs

• Hemoglobinopathies

• hodgkin disease

• thalassemia

• malaria

• myeloproliferative disorders

diseases that may lead to splenomegaly

• autoimmune hemolytic

• sever hereditary spherocytosis

• sever refractory immune thrombocytopenic purpura

• storage disorders with portal hypertension

• splenomegaly resulting in peripheral cytopenias

diseases that can be treated by splenectomy

sickle cell anemia

disease that leads to autosplenectomy

hypersplenism

relating spleen activity, not the size

• congestive splenomegaly secondary to cirrhosis of the liver and portal

• hypertension

• thrombosis

• vascular stenosis

• aneurysm of the splenic artery

• cysts

diseases leading to hypersplenism

lymph nodes

organ that is part of lymphatic system

lymph fluid

portion of the blood that escapes into the connective tissue

• characterized by a low protein concentration and absence of RBCs

spleen, lymph nodes, and other lymphoid tissue

site of mature T cells

• failure to thrive

• uncontrollable infections

• death infancy

  • caused by non-development of thymus

diseases associated with the thymus

pancytopenia

all cells decrease

amphoteric molecules

(-) or (+)

zwitterion

(-) (-) or (+) (+) at the same time

non committed/undifferentiated and committed

2 types of progenitor cells

committed

common lymphoid progenitor

• T cells, B cells, NK cells

granulocytes, erythrocytes, monocytes, megakaryocytes

common myeloid progenitor

1. monophyletic theory of hematopoiesis

2. polyphyletic theory of hematopoiesis

2 theories of hematopoietic progenitor cells

monophyletic theory of hematopoiesis

all blood cells are derived from a SINGLE progenitor stem cells

Polyphyletic theory of hematopoiesis

each of the cell lineages is derived from its own unique stem cell

hematopoietic stem cells

stem cell theory that is capable of self-renewal, pluripotent, give rise to differentiated progeny, can reconstitute the hematopoietic system

self-renewal, differentiation, apoptosis

3fates of hematopoietic stem cell

Symmetric division

daughter cells of HSCs both undergo differentiation

asymmetric division

one daughter cell self-renews, another differentiate/undergo apoptosis

stochastic

instructive

multilineage priming model

models of hematopoiesis

stochastic

randomly commits to self-renewal to differentiation

Instructive

BM microenvironment determine if cell will self renew or differentiate

multilineage priming model

cell’s fate determined by signals coming from the hematopoietic inductive microenvironment

1:1000 nucleated blood cells

ration of HSCs in bone marrow

cytokines

mitosis is stimulated by ____

mitotic index

percentage of cells in mitosis in relation to the total number of cells

• duration of mitosis

• length of resting stage

factors affecting the mitotic index