WBC Pathology 1 Flashcards
Which WBCs are considered “lymphoid”?
NK cells
T-cells
B-cells
What is the ratio of RBCs, WBCs and platelets in an adult?
What are their sizes?
600 RBCs : 1 WBC : 40 platelets.
WBC > RBC > platelet
From what embryological structure do HSCs arise? When?
When (during embryogenesis) do HSCs migrate to the bone marrow?
Mesonephros, and during the 3rd month of embryogenesis migrate to the liver (chief site of blood cell formation until shortly before birth).
4th month.
What is major site of hematopoietically-active tissue in adults?
The bone marrow of the axial skeleton.
What sites tend to have more red marrow?
Which sites tend to have more yellow marrow?
Red marrow: axial skeleton and hands/feet.
Yellow marrow: long bones (UE and LE
What is used as a marker of sepsis in neonates?
Why?
Most doctors use the band count and its derived immature-to-total neutrophil ratio.
This is used because many neonates with bacterial infections have normal or below neutrophil counths with a left-shift.
What percentage of lymphocytes exist at birth vs. at 4-6 mo.?
What changes again by 4, 6 and 8 years old?
30% of lymphocytes exist at birth and increase to 60% at 4-6 mo.
They decrease to 50% by 4 years, to 40% by 6 years and 30% by 8 years.
What is the normal range of platelets?
How much can platelet production be increased in times of need?
How long does it take to produce new platelets under normal conditions?
What is the lifespan of a typical platelet?
150K - 450K / uL
Production can increase 10x in times of need.
The intramarrow production time is about 1 week.
7-10 day lifespan.
Above 10 g/dL Hb, how is EPO released?
At what point does EPO increase logarithmically?
EPO is released at a constant rate if above 10 g/dL in response to decreased RBC mass.
If Hb is below 10 g/dL.
How much blood exists in a 70kg person?
How much is replaced daily?
How much can rates increased when needed?
5 L
1% replaced daily.
Rate can increase 5x.
What is an immature RBC termed? Why?
Reticulocyte - they contain remnant ER and ribosomes (rough ER) that forms a reticulum (net) within the RBC cytoplasm.
How large are reticulocytes?
How long do they circulate?
They are about 20-30% bigger than RBCs.
They circulate for 2-3 days and represent about 2% of the RBC population.
What occurs in the “red pulp” of the spleen?
What is recycled during this process?
Old/senescent RBCs (at about 120 days) are removed in the red pulp via macrophages that line the sinusoids.
Iron is recycled in this process.
What triggers the transition from monocyte to macrophage?
Once a monocyte leaves the intravascular space and enters tissues, it becomes a macrophage.
What is the lifespan of B-cells and T-cells?
B-cells: hours to days.
T-cells: days to years.
