"Microscopic Anatomy Bone Marrow Ira Ames" GABY

Question 1

Romanovsky Type Blood Stain*

Answer 1

Basic (+ or cationic)

• methylene blue ( RNA )
• azure B ( DNA & GAGs )

Acidic (- or anionic)
-eosin ( proteins )

Question 2

Variations on Romanovsky Type Blood Stain

Answer 2

Wright’s
Giemsa
May-Grunwald

Question 3

Hematopoiesis

Answer 3

continuous production of blood cells

Question 4

Hematopoietic organs

Answer 4

Bone marrow:
rbcs
granulocytes
monocytes

Lymphoid organs:
lymphocytes

Question 5

Monophyletic theory of hematopoiesis

Answer 5

All blood cells are derived from a common pluripotential stem cell (hematopoietic stem cell)

Question 6

Granulopoiesis

Answer 6

development of granulocytes
neutrophils
eosinophils
basophils

Question 7

Blast (precursor cell)

Answer 7

Large cell (10-15micro)
Large euchromatic nucleus
High nucleocytoplasmic ratio Heavenly blue cytoplasm
No cytoplasmic granules

Question 8

Neutrophil Differentiation

Answer 8

Condensation of nuclear chromatin
  -(disappearance of nucleoli)
Lobulation of nucleus
Appearance of cytoplasmic granules 
  -(primary & secondary)
Decrease in cytoplasmic basophilia

Question 9

Under normal conditions blasts, n. promyelocytes, n. myelocytes, and n. metamyelocytes can only be observed in bone marrow

Answer 9

True

Question 10

Where are band cells and mature neutrophils seen?

Answer 10

In normal peripheral blood

Question 11

Neutrophilic promyelocyte

Answer 11

same size as blast

spherical nucleus

more condensed chromatin

*azurophilic granules

Question 12

Azurophilic granules are ___

Answer 12

primary lysosomes

*they contain hydrolytic enzymes

Question 13

Neutrophilic myelocyte

Answer 13

round-oval nucleus

more heterochromatic

no longer makes azurophylic granules

appearance of specific granules

color of cytoplasm shifts from heavenly blue to salmon pink

Question 14

What do lysozymes and lactoferrin in neutrophil specific granules do?

Answer 14

Lysozyme: hydrolyzes glycosides in bacterial cell wall

Lactoferrin: binds iron

Together they kill bacterial cells

Question 15

Neutrophilic metamyelocyte

Answer 15

can no longer undergo mitosis

kidney-shaped nucleus (beginning of lobulation)

more condensed chromatin

numerous specific granules

few azurophilic granules

salmon-pink cytoplasm

Question 16

When can we say the metamyelocyte has differentiated into a band?

Answer 16

When the indentation exceeds 1⁄2 the diameter of the round nucleus

Question 17

Neutrophilic band

Answer 17

curved rod shaped nucleus

more condensed chromatin

cytoplasm just like mature neutrophil

can be observed in normal peripheral blood (1-5% of wbcs)

Question 18

What can the % of bands in peripheral blood provide information about?

Answer 18

They provide a rough indication of the rate of neutrophil production in your patient

Question 19

What does a shift to the left mean?

Answer 19

Increase in the % of bands in pb indicates that stress is being placed on the bone marrow to produce more neutrophils

Question 20

When can we say that the band has differentiated into a mature neutrophil?

Answer 20

When the segments between lobes have become thin heterochromatic filaments

Question 21

What is the life span of neutrophils?

Answer 21

15-20 days

9-14 days in bone marrow
1 day in peripheral blood
5 days in surrounding tissue

Question 22

What are the two types of diapedesis?

Answer 22

Paracellular (between endothelial cells)

Transcellular (through endothelial cells)

Question 23

Do eosinophils and basophils go through the same sequence of events during their maturation?

Answer 23

It is believed so and that the kinetics of the process is about the same

Question 24

What does red bone marrow consist of?

Answer 24

small blood vessels
discontinuous sinusoids
hematopoietic cords

Question 25

Where is red bone marrow found?

Answer 25

``` sternum vertebrae ribs clavicles pelvis skull ```

Question 26

Where is there more adipose tissue, red of yellow bone marrow?

Answer 26

Yellow

Question 27

What is the function of yellow bone marrow?

Answer 27

To store energy To serve as hematopoietic tissue reserve

Question 28

Hemopoietic stem cell niche

Answer 28

An interactive structural unit that nurtures stem cells and facilitates their activity

Question 29

What can we find in HSC niche?

Answer 29

Osteoclasts: create spaces in spongy bone surface Osteoblasts: play a role in the localization of stem cells, and they support hematopoiesis Other cells that may be involved: endothelial cells, pericytes, bone marrow macrophages (osteomacs) Important ecm proteins: fibronectin, laminin, agrin

Question 30

Importance of the hematopoietic stem cell niche

Answer 30

Hematopoietic stem cells are not randomly distributed in bone marrow They live in specific microenvironments called stem cell niches Interaction of the stem cells with the elements of the stem cell niche (cellular & ecm) is critical Alterations to the hematopoietic stem cell niche can lead to myeloproliferative disease, that is a preleukemic condition

Question 31

Erythrocyte differentiation

Answer 31

Decrease in cell volume Decrease in nuclear diameter Increase in heterochromatin Disappearance of nucleoli Loss of nucleus Decrease in cytoplasmic basophilia Increase in cytoplasmic eosinophilia (due to accumulation of Hb)

Question 32

Basophilic erythroblast (BEB)

Answer 32

First recognizable stage in erythropoiesis Smaller than a blast Checkerboard nucleus Loss of nucleolus Navy blue cytoplasm (due to increase in free ribosomes which participate in production of Hb) Capable of cell division (1-2 times)

Question 33

Polychromatophils are capable of dividing ___ times

Answer 33

3-4

Question 34

Normoblast (NB)

Answer 34

smaller cell smaller heterochromatic nucleus slightly polychromatophilic cytoplasm terminal cell: can no longer undergo mitosis

Question 35

What is the fate of normoblasts?

Answer 35

1. 80% become reticulocytes | 2. 20% become orthochromatic erythroblasts

Question 36

Maturation time for RBCs

Answer 36

Total time: 8-9 days 1-2 days as a basophilic erythrocyte 3 days as a polychromatophil 3 days for normoblast to reticulocyte transition 1 day for reticulocyte to RBC transition

Question 37

Orthochromatic erythroblast (OCE)

Answer 37

Uses up its residual RNA before it extrudes its nucleus Resembles a nucleated rbc *not present in normal peripheral blood

Question 38

Erythropoietin

Answer 38

Glycoprotein hormone Produced in the kidney cortex (probably by endothelial cells of the peritubular capillary plexus) Increases rate of mitosis (in blasts, basophilic erythroblasts and polychromatophils) Increases RNA synthesis in developing rbcs (especially mRNA for hemoglobin) Attenuates the degree of brain damage after stroke Synthesis is stimulated by hypoxia

Question 39

Erythroblastic island

Answer 39

Developing rbcs cluster around reticular cells in bone marrow Reticular cells phagocytose extruded nuclei

Question 40

Plasma cell (in marrow smear)

Answer 40

basophilic cytoplasm negative image of Golgi acentrically placed nucleus “clock face” chromatin

Question 41

Megakaryocyte Differentiation

Answer 41

Cell enlargement Lobulation of nucleus Increase in level of ploidy ( 32-64n ) Shift in cytoplasmic basophilia to acidophilia Accumulation of azurophilic cytoplasmic granules Formation of platelet demarcation channels

Question 42

Proplatelet model of platelet production

Answer 42

1. Extension of thick pseudopods 2. Formation of long extensions (proplatelets) 3. Platelets are released from ends of proplatelets

Question 43

Megakaryocytes

Answer 43

Megakaryocytes lie just outside of the discontinuous sinusoids They release platelets into the lumen of the sinusoids Platelets circulate for about 10 days They are then destroyed within the spleen and liver They contain a functional repertoire of mRNAs Platelets may be able to produce functional progeny??

Question 44

Lymphocyte Differentiation

Answer 44

Decrease in cell size Condensation of chromatin Disappearance of nucleoli Acquisition of cell surface receptors * Some cells migrate to the thymus (T lymphs) * Some cells begin differentiation in the bone marrow (B lymphs)

Question 45

Monocytes

Answer 45

bone marrow (2-3 days) circulation (1-2 days) tissues (as macrophages) (1-3 months)