Unit 3: Blood Part C Flashcards
Hematopoiesis
Production of formed elements (blood cells) from pluripotent hematopoietic stem cells found in
bone marrow
Pluripotent hematopoietic stem cells
develop into many diff. cell types
as they specialize, they narrow their possible fates
1st - become UNCOMMITTED STEM CELLS
2nd - then PROGENITOR CELLS that are committed to developing into RBC’s, lymphocytes, other WBC’s, & megakaryocytes (parent cells of platelets)
Bone marrow
a soft tissue that fills the hollow center of bones
Red marrow
active hematopoiesis (25% of overall production = RBCs, 75% = WBCs)
Yellow marrow
= adipose cells, inactive hematopoiesis
List the formed element of blood
- Erythrocytes (Red Blood Cells or RBCs)
- Leukocytes (White Blood Cells or WBCs)
a. Lymphocytes – produced directly from Pluripotent stem cell.
b. Monocytes
c. Neutrophils
d. Eosinophils
e. Basophils (in tissues = mast cells) - Platelets (formed from megakaryocytes)
What are the 5 types of mature Leukocytes (WBC’s)?
a. Lymphocytes
b. Monocytes
c. Neutrophils
d. Eosinophils
e. Basophils
Erythrocytes (Red Blood Cells or RBCs)
- have LOST their nuclei by the time they enter the bloodstream
- key role in transporting O2 from lungs to tissues, & CO2 from tissues to lungs
Leukocytes (White Blood Cells or WBC’s)
- ONLY functional cells in the circulation
- key role in body’s immune response, defending the body against foreign invaders (parasites, bacteria, & viruses etc.)
- most circulate through the body in the blood, but their work is usually carried out in the tissues rather than in the circulatory system
Platelets
cell fragments that split off a large parent cell known as a megakaryocyte
primary function is hemostasis
Lymphocytes
responsible for acquired immune response
sometimes called immunocytes
Monocytes
phagocytes; after migrating into tissues, they develop into MACROPHAGES
Neutrophils
mobile phagocytes that ingest foreign substances & pathogens release cytokines
Eosinophils
produce toxic compounds directed against invading pathogens
allergic reactions
Basophils
tissue basophils are also called MAST CELLS
release histamine, heparin
What is collectively known as Phagocytes? Why?
Monocytes, Macrophages (what monocytes dev. into), & Neutrophils
b/c they can engulf & ingest foreign particles such as bacteria (phagocytosis)
What controls the production and development of blood cells?
cytokines: peptides or proteins released from one cell that affect the growth or activity of another cell
List the 4 different types of cytokines:
- Interleukins
- Erythropoietin
- colony stimulating factors
- thrombopoietin
Interleukins
variety of functions including stimulation of uncommitted stem cells to form committed progenitor cells.
Produced and released by WBCs to act on other WBCs
Erythropoietin (EPO
Ø stimulates erythropoiesis (red blood cell production)
Ø produced and released by the kidneys in response to low
oxygen levels (hypoxia)
People who are adapted to live at
high altitude have a higher hematocrit as a result.
Ø Erythroblasts (nucleated) –> Reticulocyte—> Erythrocyte (anucleate
Colony Stimulating Factors (CSFs)
Ø stimulate leukopoiesis (white blood cell production)
ØSecreted by endothelial cells and fibroblasts in bone marrow, and by other leukocytes.
ØResponds to need. (e.g. during bacterial infection, CSFs stimulate production of neutrophils and monocytes.; viral infections cause increase in proportion of lymphocytes).
Thrombopoietin (TPO)
Ø regulates growth and development of megakaryocytes (and
therefore platelet production).
ØProduced and secreted by the liver
