Haematopoeisis Flashcards
What percentage of the blood is haemocrit?
42
Where is the primary site of haematopoeisis from month 7?
Bone marrow
What are totipotent stem cells?
Stem cells capable of producing all the cells in an organism
What are pluripotent stem cells?
Produces endoderm, mesoderm and ectoderm.
From which kind of stem cell do all blood cells arise?
A common pluripotent stem cell
What is a unipotent stem cell?
Stem cells restricted to producing a single lineage incapable of cell renewal
What are haematopoeitic stem cells?
Stem cells that produce all circulating blood cells
What is the hierarchy of stem cells?
Totipotent, pluripotent, multipotent, unipotent, haematpoeitic
What is a multipotent stem cell?
Stem cell that divides in to multiple but restricted cell types
Describe the blood flow into, through and out of the bone marrow
In via the nutrient artery, then a radial artery which enters the cortex via the endosteum, then the cortical capillaries, then the endosteal capillaries, then a central sinus, then the emissary vein.
What is the precursor of a erythrocyte?
Normoblast
Describe the formation of an erythrocyte from its precursor
Normoblast, contains most of the hb but has mitochondria and ribosomes
After the nucleus is ejected it’s called a reticulocyte then RNA and organelles are removed forming the final rbc
From which precursor are platelets derived?
Megakaryocyte
How are platelets formed?
From megakaryocytes via thrombopoeitin
What are the types of leukocyte?
Neutrophils, basophils, eosinophils
What does PMN mean
Polymorphonuclear
Describe neutrophils ability to divide
Unable
What is the capacity of a neutrophil to synthesise proteins
Little capacity
Give examples of inflammatory diseases in which neutrophils can damage healthy tissues
MS, COPD, rheumatoid arthritis
What are uropods and pseudopods used for in the motility of a neutrophil?
They are lobes of the cell produced in response to a chemokine. The uropod acts like an anchor and pseudopods produced act as sensors which then move in the direction of an increasing chemokine concentration
What is the life span of an eosinophil in the blood stream?
8-12hrs
What are the functions of monocytes?
Defends against microorganisms
Removes tissue debris
Can trigger an immune response and secrete cytokines
What are the two types of lymphocyte?
B and T cells
What are the types of t lymphocytes
Cytotoxic and helper
