CH 4 Hematopoiesis

What are the 3 aspects of hematopoiesis that are carefully balanced?

cellular proliferation, cellular differentiation, and cell death

Describe the process of cellular proliferation & what it is governed by.

process of replacing circulating cells

governed by multiple cytokines (both stimulating & inhibiting)

Describe the process of cellular differentiation

process of generating diverse cell populations (unspecialized → specialized)

Checkpoint

HPCs and maturing cells are undergoing death by differentiation, why?

Because their population isn’t maintained by self-renewal unlike HSC’s.

What is the terminology for HSCs when they’re dormant? What type of division do they undergo and what is it?

quiescent/G0

Asymmetric division (where they produce on HSC and a HPC)

What is the stem cell marker for HSCs?

CD34+

What are the 2 progenitor lineages that HPC’s can differentiate into? And what type of cells do they give rise to?

common lymphoid progenitor (CLP) that give rise to B-cells, T-cells, and NK cells

common myeloid progenitor (CMP) that give rise to the myeloid & erythroid cells

What is the earliest recognizable cell for maturing cells?

Blast cells (lymphoblast, myeloblast, megakaryoblast)

Checkpoint

Self-renewal and multipotential differentiation are characteristic of what type of cell?

HSC’s

Checkpoint

Precursor cells that are morphologically recognizable are found in what compartment?

maturing cell compartment

Checkpoint

Which clinical lab discipline may be used for differentiating non-morphologically recognizable cells?

Flow cytometry

Which cell type is not derived from the common myeloid progenitor?

lymphocytes

Which cytokine signals HSC’s to NOT undergo apoptosis?

Stem cell factor (SCF, IL-1)

What does redundancy and pleiotropy mean in regards to cytokine control of hematopoiesis?

Redundancy: multiple cytokines have similar effects

pleiotropy: a single cytokine can affect multiple lineages

Checkpoint

True/False: A lymphocyte in the G₀ phase has permanently lost its ability to divide

False

Checkpoint

True/False: All mature lymphocytes have relatively short lifespans & must be continuously replaced by the BM

False