Lecture 7 Flashcards
With in the first two weeks of embryonic life what blood cell is produced by the yolk sac?
Primitive red cell
What type of WBC is produsted 1st?
Granulocytes
What is the 1st major stage of Hematopoietic Development?
Mesoblastic Period (Yolk Sac Phase)
What is the 2nd major stage of Hematopoietic Development?
Hapatic Period
What is the 3rd major stage of Hematopoietic Development?
Medullary (Myeloid Phase AKA Bone Marrow)
When does the Mesoblastic Period begin?
Around the 19th day of embryologic development.
When doe the Mesoblastic Period end?
Around 8 weeks (or 2 months) of gestation.
What are the Hematopoietic products produced during the Mesoblastic Period?
- Portlans
- Gower 1
- Gower 2 HgBs
When the the Hepatic Period usually start?
Begins at 4-5 weeks of gestation.
How long does the Hepatic Period last?
It ends just before birth.
Where does the Hepatic Period take place?
Liver
Where does the Mesoblastic Period take place?
THe Yolk Sac
What are the Hematopoictic products produced during the Hepatic Period?
- Primitive and definitive erythoblasts
- Granulocytes, monocytes, lymphocytes, megakaryocytes
- Hemoglobins F, A, and A2
What other tissue produces blood cells during the Hepatic Period besides the Liver?
Spleen
What Period is 1?
Mesoblastic
What Period is 2?
Hepatic
What Period is 3?
Medullary
Where does 1 take place?
Yolk Sac
Where does 2 take place?
Liver & Spleen
Where does 3 take place?
Boan Marrow
When does the Medullary Phase begin?
Usually begins between the 4th and 5th month of fetal gestation.
Where does the Medullary (Myeloid) Phase take place?
In the the medulla or inner part of the bone marrow.
When does the bone marrow become the primary site of hematopoiesis?
By the sixth month of age.
What Hematopoietic products produced at this time?
- Various stages of all cell lines
- EPO: Erythropoietin
- Fetal and adult hemoglobins
When does red marrow turn into fatty yellow marrow?
Around the age of 5-7 years.
How much bone marrow is found in adults?
Only about 50% of the bone marroe is red marow.
Where can the red bone marrow befound in a adult?
- Skull
- Clavicle
- Sternum
- Ribs
- Vertebrae
- Pelvis
- Proximal ends of the hurmerus and femur.
What is Retrogression?
The process of replacing the active marrow by adipose tissue during development into adulthood.
What is Extramedullary Hematopoiesis?
In some diseases, the spleen and liver may also become sites of blood cell production.
Under what kind of conditions can the 50% of yellow marrow found in adult be converted back to red?
Extreme
What does Medullary Hematopoisis mean?
- Normal condition
- 50% / 50% adult bone marrow is red / yellow
- Bone marrow is the major site of hematopoiesis
What does Extramedullary Hematopoiesis mean?
- Abnormal condition
- 100% of the bone marrow is engaged in hematopoiesis
- The spleen and liver also become sites of hematopoiesis
All blood cells arise from?
Stem cells
Where is the stem cells found?
The red bone marrow.
Stem cells, which have the ability to reproduce and differentiate, comprise less than what % of the marrow cells?
1% of the marrow cells
What are stem cells thought to resemble?
A small lymphocyte.
What are the 3 Lymphatic Organs?
- Spleen
- Lymph nodes
- Thymus
Whic is the larges lymphoid organ in the body?
Spleen
What are the 3 major areas of the spleen?
- White pulp
- Marginal zone
- Red pulp
What does the White pulp do in the Spleen?
It contains Follicles with germinal centers.
What does the Marginal pulp do in the Spleen?
It Separates the red and white pulp.
What does the Red pulp do in the Spleen?
Vascular sinusoids and sinuses separated by the cords of Billroth, which contain sensitive macrophages.
What does the spleen do for the blood?
It acts as a filter for the blood.
What is the normal RBC life span?
120 days
How does the spleen know when the RBC gets to old.
This inflexibility along with a reduced glucose environment target old RBCs for destruction and recycling by the macrophages of the spleen.
What happens when a RBC ages?
It becomes inflexible.
What is this a slide of?
Autoimun Hemolitic Anemia
What is the cell at the arrow?
Macrophage Ingesting RBCs
What is happening in this cell?
Recycling Iron
What is this cell called?
Hemosiderin laden Macrophage
What is this cell called?
Hemosiderin laden Macrophage
What does CFU-S stand for?
colony-forming unit-spleen
What are colony-forming unit-spleen?
Colonies of hematopoietic stem cellsthat were seen on the spleens of the irradiated mice that were intravenous injection with marrow cells.
Stem cells are capable of what?
- Self-renewal
- To give rise to differentiated progeny
- Able to reconstitute the hematopoietic system of a lethally irradiated host.
What does the Immature Cells Cytoplasm look like?
Deep blue, scanty amount.
What does the Immature Cells Nucleu look like?
Large, round to oval; Reddish-purple chromatin that appears fine and delicate; nucleoli present; high N/C ratio (4:1).
What size is the Immature cell?
Large
What size is the Mature cell?
Smaller then the Immature Cells
What does the Mature Cell’s Cytoplasm look like?
Lighter blue, more abundant cytoplasm
What does the Nucleus look like in an Mature Cell?
Smaller nucleus, bluish-purple chromatin with some clumping; no nucleoli; smaller N/C ratio (1:1)
What is the N/C ratio of a Myelonlast or Blast?
4:1
What does the chromatin look like in a Blast?
Nuclear chromatin stains reddish-purple and appears fine and delicate, with NO CLUMPING.
Are the Nucleoli present in Blast?
Yes
What does the cytoplasm look like in a Blast?
Cytoplasm stains moderately blue (from the presence of RNA & protein production) with NO GRANULES.
Is a Blast normally found in the peripheral blood (PB)?
NO
Why is a Myoblast a nonfunctional cell?
Because it is incapable of motility, adhesion, and phagocytosis.
The Myeloblast begins to down regulate the expression of CD34 and will start to express what?
CD13 and CD33
What stage of cell development does Primary Azurophilic (Nonspecific) Granules Appear?
In the Promyelocyte stage.
What color are the granules are in the Prommyelocyte?
They are dark blue or reddish-blue, and usually overlay the nucleus.
Are Promyelocytes normaly found in the PB?
NO
Can the Promyelocyte be larger then the blast?
Yes
What does the nucleus look like in the Promyelocyte?
Round to oval nucleus, occupies half or more of the cell.
What does the Promyelocytes nuclear chromatin look like.
Are Nucleoli present in Promyelocytes?
YES
What does the cytoplasm look like in the Promyelocyte?
light blue
In which stage of the Myeloblast line do Secondary (Specific) Neutrophilic Granules form?
In the Myelocyte stage.
In the Myeloblast line which stage is the last stage able to go through Mitosis?
Myelocyte stage
What help are the secondary granules to MLS’s when looking at the Myeloide Line?
They helps to identify the cell as eos, baso, or neutrophil.
What is the Dawn of Neutrophilla?
A light area adjacent to the nucleus that contains the Golgi apparatus of the cell.
What is the Dawn of Neutrophilia a sign of?
The first sign of neutrophil differentiation.
What stage of probuction is the Myelocyte?
3
What stage of probuction is the Promyelocyte?
What stage of probuction is the Metamyelocyte?
4th
What is the sign that a Myelocyte is turning into a Metamyleocyte?
The Nucleus begins to indent but less than 50%
What does the Nucleus look like in the Metamyelocyte?
Is often “kidney-shaped” with chromatin that is coarse and is showing clumping.
What collor are the cytoplasmic granules in the Metamyelocyte stage?
More pink
In what extream cases can the Metamyelocyte be found in the PB and what does this tellthe physician?
evere bacterial infections such a sepsis, there may be a few metas in the PB along with many segs and bands! This tells the physician that the infection is very severe.
Are Myelocyte’s usualy found in the PB?
No
