(ADD ON CH.10) blood and formed elements

1 oct. 2025

Erythrocytes, lymphocytes, and platelets are _________?

formed elements

Before birth, where does blood cell formation take place?

In the fetal yolk sac, liver, and spleen

By the seventh month of formation in embryo/fetal development, ________ is the primary hematopoietic area?

red bone marrow

Where do blood cells develop from?

mesenchyme-derived cells called blood islands

formation in embryo and fetal development. (idk if we need to memorize)

All formed elements arise from the common _____ ______ ____ ____?

pluripotent hematopoietic stem cell

1. What are the two lineages that hematopoietic stem cells develop along?

2. What determines these lineages?

(1) Myeloid lineage - Myeloid stem cells - Give rise to all other blood cells

(2) Lymphoid lineage - Lymphoid stem cells - Give rise to lymphocytes

“Signals are what determines these lineages.”

Formation of Formed Elements of Blood (not sure to memorize either)

Q: Blood stem cells give rise to which two lines of progenitor cells?

myeloid stem cells & lymphoid stem cells

Q: Which celll do NOT develop from the differentiation of myeloid stem cells?

lymphocytes