Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

COT pt. 2 > Lecture/Lab: Hematopoiesis & Bone Marrow > Flashcards

Lecture/Lab: Hematopoiesis & Bone Marrow Flashcards

1
Q

Sites of Hematopoiesis

A

Yolk Sac, Liver, Bone Marrow, Red Marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Yolk Sac Hematopoiesis

A

extraembryonic site
hematopoietic islands form here in the 3rd-4th week of gestation, peaking in 2nd month

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Liver (and Spleen) Hematopoiesis

A

hematopoiesis begins here in the 5th week, peaks at 5-6 months gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Bone Marrow Hematopoiesis

A

hematopoiesis begins here in the
5th month of gestation, continues to adulthood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Red Marrow Hematopoiesis

A

limited to specific locations after
puberty
Location of RM: heads of long bones, rib cage, vertebral columns, pelvis, sternum

After puberty, red marrow typically is confined to the metaphyseal regions of long bones and to the axial skeleton. The crest of the iliac bone (the prominence one feels at one’s hips) is the preferred site for marrow biopsy as it is the part of the axial skeleton furthest away from CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Yellow Marrow vs. Red Marrow

A

Yellow- Higher proportion of adipose tissue
Red- Higher proportion of Hematopoietic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Macrophage Sequestration (Storage)

A
  • stored in spleen (as monocytes)
  • rapid deployment during tissue repair (ie myocardial infarction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Neutrophil Sequestration (Storage)

A
  • “Marginated pool” PMNs (neutrophils) are adherent to endothelial cells
  • Postcapillary venules of lung is largest site of marginated (adhered) pool
  • normally 1/2 of PMNs are marginated (explains why CBC doesn’t tell the whole story)
  • released in response to stress,
    epinephrine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Lymphocyte Sequestration (Storage)

A

stored in secondary lymphatic organs (MALT, BALT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Vasculogenesis

A

-The creation of a vessel out of CT
-MET event (mesenchymal to epithelial transition)
-Embryonic event, doesn’t happen in adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Extraembryonic Hematopoiesis

A

Early blood and vessels come from the same source in extraembryonic (lateral sphlancnic) mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Blood island

A

collection of 1st progenitor cells of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Angiogenesis

A

-The sprouting of vessels from existing vessels
-Happens in adults
-Occurs in response to lack of oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Tip cells

A

special endothelial cells that direct the formation of new vessels (via angiogenesis) by pulling stalk cells into vascular lumens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hematopoietic tissue composition

A

The composition of hematopoietic tissue changes based on site, particularly for monocytes, neutrophils and dendritic cells, which are first found in bone marrow

This is expected because the needs of the embryo, fetus, and adult are different

Progenitors of the “organ-colonizing” cells are specific to liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Composition of the vascular compartment of bone marrow

A

vascular sinus
(large, sinusoidal capillaries)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Composition of the hematopoietic compartment of bone marrow

A

stroma (supporting tissue):
- adipose tissue
- fibroblasts
- connective tissue
- endothelium
parenchyma (“functional” tissue):
- developing blood cells (hematopoietic islands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Origin of each type of stromal cell

A

Derived from MSC
- Osteoblasts (secrete collagen & fibronectin for new bone)
- Adipocytes (store fat)
- Fibroblasts (secrete ECM)
- Endothelial cells (vascular lining)

Derived from HSC
- Osteoclasts (secrete protons, etc., to break down bone)
- Macrophages (phagocytic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Stem cell

A

From Video:
A cell that can both renew itself (divide and create a daughter cell that is also a stem cell) and is totipotent (has ability to generate all of the cell lines that are found within that system)
ex: a cell that can create all of the cells of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Progenitor cell

A

From Video:
A cell that can renew itself, but cannot produce the whole lineage (multipotent)
ex: a cell that can produce lymphocytes, but none of the other blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Precursor cell

A

From Video:
Cannot renew itself. If it divides, differentiation will go along with it. The daughter cells must be more differentiated than the parent cell. Restricted to one particular lineage of adult cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What two classes of progenitor cells are produced from hematopoietic stem cells? (classical view)

A

Common Myeloid Progenitor (CMP)
- erythrocytes
- platelets
- macrophages
- granulocytes

Common Lymphoid Progenitor (CLP)
- lymphocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What cells are produced from each class of progenitor cells? (classical view)

A

CMP (common lymphoid progenitor) which gives rise to:
– CFU- Eo (eosinophils)
– CFU- B (basophils)
– CFU -GM –> CFU-G (neutrophils) & CFU-M (monocytes)
– CFU-Megakaryocyte
– BFU-E (burst-forming unit - erythrocyte) –>CFU-E (erythrocytes)

CLP (common lymphoid progenitor) which gives rise to:
– CFU- LyT
– CFU- LyB

24
Q

What are the precursor cells in blood and what cells result from them?

A

The first precursor cell in each lineage is a “blast”.
– Proerythroblasts ultimately form erythrocytes.
– Myeloblasts ultimately form granulocytes.

25
Q

What are CD markers and why are they important?

A

Because stem cells and progenitor cells are not morphologically distinguishable, they are recognized (and defined) in laboratories by using combinations of CD markers, made from monoclonal antibodies for surface proteins. CD markers such as CD-4 and CD-8 are famously used to distinguish different subtypes of T-cells. (from lecture notes)

presence (+) or absence (-) or even
the level of expression (lo, hi) of a
CD molecule can be used to define
a developmental stage.
CD expression can be dependent
on lineage and/or on stage of
differentiation.

CD4+ (Helper T cell)
CD8+ (Cytotoxic T cell)
CD3+ part of developing T cells

26
Q

What are the erythrocyte precursor cells?

A

Proerythroblast, Basophilic erythroblast, Polychromatic erythroblast, Orthochromatophilic erythroblast, and reticulocyte

27
Q

What is the main way to distinguish between erythrocyte precursor cells?

A

precursor cells are chiefly distinguished by their cytoplasmic coloration

Less important characteristics are the size of the cell (goes from large to small), the size of the nucleus (big to small), the chromatin (euchromatic to heterochromatic)

28
Q

Basophilic erythroblast

A

Contains all ribosomes, which make the cytoplasm basophilic

We need a lot of ribosomes to make proteins (hemoglobin)

Fine chromatin clumps in nucleus, basophilic cytoplasm

Large (usually slightly smaller) cell with basophilic cytoplasm but lacking nucleoli

29
Q

Polychromatic erythroblast

A

Begins to produce hemoglobin which is eosinophilic
mix of ribosomes & hemoglobin

Coarsechromatin clumps in nucleus, grey-blue cytoplasm, last stage for mitosis

average-sized cell with a cytoplasm intermediate in color between basophilic and eosinophilic extremes

30
Q

Orthochromatophilic erythroblast

A

Means “identical color”

Same color as erythrocyte

all hemoglobin

average-sized cell with a cytoplasm equivalent in color to that of the reticulocytes

31
Q

Reticulocyte

A

No nucleus, but does have some remnant organelles (not visible)
On marrow smear, assume all RBCs are reticulocytes

small, spherical eosinophilic cell lacking a nucleus. Remnants of intracellular organelles can be visualized with special stains

Nucleus gone, fine strands in cytoplasm, frequency in peripheral blood depends on hematopoietic activity

Shape is intermediate between spheroid and biconcave RNA and intracellular organelles still retained

Not easily visualized in WrightGiesma stains – methylene blue is typically used for reticulocyte counts

Very important part of a clinical
blood workup. They will count reticulocytes which should be around 2%

32
Q

Erythropoiesis

A

Erythropoiesis is the process by which red blood cells (RBCs) are produced in the bone marrow

Erythropoiesis is regulated by substances normally present in marrow stroma:
– G-CSF (granulocyte colony stimulating factor),
– SCF (stem cell factor)
– IL3
– The cytokine Erythropoietin (EPO) (made in kidney corticointerstitial cells), which is itself regulated by:
* Oxygen levels
* Renin-Angiotensin system (sensing blood pressure)
* Other hormones, for example insulin

33
Q

Erythrocyte progenitor cells

A

CMP – generates all non-lymphoid lineages.

BFU-E – progenitor cell
- requires several cytokines for survival
- high proliferative potential
- 14 days to RBCs in culture
- motile – can be present in peripheral blood

CFU-E – progenitor cell
- highly dependent on EPO
- 7 days to RBCs in culture
- non-motile, found in marrow only

34
Q

Proerythroblast

A

Nucleoli present in nucleus,
no granules in cytoplasm

Large cell with nucleoli and cytoplasm that can range from neutral to basophilic. In common preparations, it is not distinguishable from the myeloblast

35
Q

What does increased reticulocyte count mean?

A

internal bleed or chronic anemia because marrow is pumping lots of reticulocytes into blood

36
Q

How to reticulocytes and granulocytes leave the marrow?

A

Reticulocytes leave the marrow by piercing through endothelial cells

Mitochondria and polysomes still finishing the production of hemoglobin

Biconcave erythrocyte shape is formed within the circulation

Reticulocytes leave the marrow, and are normally present at < 1.5% in peripheral blood.

Granulocytes leave the marrow as either band cells or mature forms. Band cells are normally present at about 3% in peripheral blood.

37
Q

What are the 3 types of granules that neutrophils have?

A

primary (azurophilic): lysosomes
secondary (specific, i.e. neutrophilic,
eosinophilic, basophilic)
tertiary: chemotactic

38
Q

How to distinguish blast cells? (proerythroblast and myeloblast)

A

Large cell, large nucleus, prominent nucleolus (large white spaces)

39
Q

What is the order of the neutrophil and eosinophil lineage?

A

Myeloblast –> Promyelocyte –> Early neutrophilic/eosinophilic myelocyte –> Late neutrophilic/eosinophilic myelocyte –> Neutrophilic/Eosinophilic metamyelocyte –> Band cell (only for neutrophils) –> Mature neutrophil/eosinophil

40
Q

What type of granule is present in each stage in the granulocyte lineage?

A

Myeloblast: no granules present

Promyelocyte: primary (azurophilic) granules

Early neutrophilic/eosinophilic myelocyte: secondary (specific) granules

41
Q

Early neutrophilic/eosinophilic myelocyte

A

round nucleus

specific granules begin to accumulate intracellularly.

few specific granules

42
Q

Late neutrophilic/eosinophilic myelocyte

A

kidney shape nucleus

many specific granules

43
Q

Neutrophilic/Eosinophilic metamyelocyte

A

V-shape nucleus

V-shaped nucleus, i.e. containing an acute angle indentation. Basophilic metamyelocytes are not normally distinguished in LM because the basophilic granules (unlike eosinophilic granules) obscure the outline of the nucleus.

44
Q

Band cell

A

C-shaped nucleus, without chromatin
bridges

immature form of neutrophil normally present in peripheral blood in small quantities, but over 2% can indicate pathology

C-shaped nucleus (usually no acute indentations), but be careful to consider the orientation of the cell on the slide. Normally present at about 2% in peripheral blood.

45
Q

Monocyte development

A

Progenitors: CFU_GM, CFU-M
Precursors: monoblast, promonocyte
In blood: circulating monocyte
In tissue: macrophages, dendritic cells, osteoclasts

46
Q

Lymphocyte development

A

Progenitors: CFU-Ly, CFU-LyB, CFU-LyT
Precursors: lymphoblast, prolymphocyte
In blood: circulating lymphocytes
In tissue: Ly-B (B lymphocyte), Ly-T (T T lymphocyte), NK-cells (natural killer cells), interstitial plasma cells

47
Q

Megakaryocytes

A
  • Reside exclusively in bone marrow, are HUGE cells (100 μm in diameter)
  • Release pre-platelets into sinusoid/sinus capillary, which mature into platelets in circulation
  • Polyploid cells (one nucleus but many copies of DNA) as a result of endomitotic division in megakaryoblasts
  • Megakaryocytes with higher chromosome content produce more platelets than megakaryocytes with low chromosome content.
  • Platelet demarcation channels form in cytoplasm
  • 8000 platelets produced per
    megakaryocyte
  • Platelets (pre-platelets) are pinched off within the lumen
48
Q

Life cycle of a platelet

A

platelets are pinched off from megakaryocytes in bone marrow & released into circulation

(megakaryocytes are capable of altering the rate of platelet production over an entire order of magnitude)

activated in response to clotting factors

typically activated outside the circulation, or by exposure to basal
surface of endothelia

normally last about 10 days *

“stored” in circulation

49
Q

Primary lymphoid organs

A

Bone Marrow and Thymus

Responsible for generating and maturing lymphocytes

50
Q

Anemia

A

disorders of RBCs

Reduction in the oxygen carrying capacity of the blood

Causes include:
– Blood loss via trauma or genetic defects
– Kidney disease (kidney and liver make erythropoietin)
– Bone marrow cancer

Too few RBCs
- Too few produced
- Too many lost or destroyed
Too many RBCs (polycythemia)
- Right number of RBCs, but:
Too small
Too large
Wrong shape (ex: sickle-cell anemia)

51
Q

Leukemia

A

disorders of WBCs

52
Q

Basic classification of leukemia

A

First letter:
– A for Acute = few mature circulating WBCs
– C for Chronic = abnormal function in circulating WBCs

Second letter (which progenitor):
– M for Myelogenous = affecting myeloid cells
– L for Lymphocytic = affecting lymphocyte cells

Third letter:
– L for Leukemia = abnormal proliferation of leukocytes, sometimes called ‘cancer of the blood’

53
Q

Acute Leukemias

A

Very few mature leukocytes (WBC’s) in blood. Blood may contain cells normally found in marrow.

Marrow is full of rapidly dividing immature cells that do not differentiate.

Anemia and bleeding are common as normal cells in marrow are affected by crowding.

Treatments include drugs, radiation, bone marrow transplants and autologous stem cell transplants.

54
Q

promyelocyte

A

smaller cell with nucleoli and azurophilic granules appearing, often near the Golgi.

55
Q

mature neutrophil, eosinophil, basophil

A

segmented nucleus. Granulocytes usually leave marrow in their mature form, though in case of demand, late precursors may also leave.

56
Q

Platelet demarcation channels

A

cytoplasmic structures which precede the formation of the proplatelet strings, are recognizable EM features of megakaryocytes

COT pt. 2 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions