Blood Components Flashcards
Function of Blood (3)
Transportation (gases, heat, nutrients, waste)
Protection
Regulation
Formed elements (3)
RBCs
WBCs
Platletes
Haemopoesis
= development of formed elements of blood
Site of haemoposesis before birth?
1st in yolk sac…later in spleen, thymus + lymph nodes of foetus
Main site of haemopoesis (last 3 months before birth)
red bone marrow
Describe red bone marrow
Highly vascularised connective tissue
In macroscopic spaces between trabeculae
0.05-0.1% of red bone marrow =
= PLURIPOTENT STEM CELLS
PLURIPOTENT STEM CELLS (derivative + function)
Derived from mesenchyme (tissue from which almost all connective tissue develop)
Have capacity to develop into many different types of cells
Red to Yellow Bone Marrow Transition?
All RED in newborns
As person ages rate of blood cell formation decreases
Red bone marrow in long bones becomes inactive (replaced with YELLOW bone marrow)
What can pluripotent stem cells divide into (what can they develop into?)
Myeloid Stem Cells (develop into: platelets, WBCs, RBCs)
Lymphoid Stem cells (develop into lymphocytes)
Precursor cells?
“…blasts”
Over several divisions
Develop into formed elements of blood
Progenitor cells? (what can they become)
No longer capable of reproducing themselves
Some becoming colony-forming units (CFU)
Become other types of blood cell but not themselves?
Name 3 types of Hematopoietic Growth Hormones
Erythropoietin (EPO)
Thrombopoietin (TPO)
Cytokines
Function of erythropoietin
Increases no. of red blood cell precursors
Mainly in kidneys
Function of thrombopoietin
Hormone produced by liver
Stimulates platelet formation
Function of cytokines
Regulate development of different blood types
Small glycoproteins
Act as local proteins
Stimulate proliferation of progenitor cells
Regulate non-specific immune cell activities + immune responses
Cytokine Families (stimulate WBC formation) (Colony-stimulating factors, Interleukins)
Why do males have higher hematocrits?
Higher due to higher levels of testosterone
Stimulates erythropoietin = stimulates production of RBCs
Anemia vs Polycythemia
Anemia = lower hematocrit than normal
Polycythemia = abnormally high hematocrit (>65%)
Raises blood viscosity + blood pressure (due to increases resistance to flow)
RBCs plasma membrane
Strong flexible plasma membrane
Allows them to deform without rupturing (when squeezing through narrow capillaries)
What causes different blood types?
different glycolipids
Pro + Con of RBCs lacking nucleus + organelles
Cant reproduce / carry out metabolic activities
More room to carry O2
Structure of haemoglobin
Contains proteins (haem) 4 polypeptide chains (2 alpha, 2 beta)
Contain ring like non-protein pigment (heme) bound to each of 4 chains
Centre of heme ring = Fe2+
RBCs contain enzyme carbonic anhydrase which catalyses…
CO2 + H2O → ← H2CO3 → ← H+ + HCO3-
How to tell the difference between granular + agranular WBCs?
(Granular = …“phil” )
Agranular =… “cyte”
How do WBCs leave the bloodstream?
Roll along vessel + stick to endothelium
Squeeze between endothelial cells
Adhesion Molecules in WBCs (+ selectins and integrins)
Help WBCs to stick to endothelium
“selectins” = displayed on surface of endothelial cells
(Response to injury + inflammation)
Stick to carbs on surface of neutrophils
Cause them to slow down + roll
“Integrins” = tether neutrophils to endothelium
Chemotaxis (neutrophils + macrophages) + stimulus
= Different chemicals released by microbes (attract phagocytes)
Stimuli for chemotaxis = kinins (specialised products of damaged tissues)
Defensins (neutrophils + macrophages) + action
= Proteins in neutrophils
Board range of antibiotic activity
Form peptides spears (poke holes in microbe membrane)
Loss of cellular contents = kill invader
Action of eosinophils
Released by enzymes combatting substances involved in inflammation
Phagocytosis antigen-antibody complexes
Action of basophils
Leave capillaries at inflammation site (enter tissues)
Enter tissues + release granules
Contain heparin, histamine + serotonin
Intensify inflammation
Mast Cells
Release substances involved in inflammation
Widely dispersed in connective tissues
Main types of lymphocyte + function (3)
B cells (destroy bacteria + inactivate their toxins) T cells (attack infected cells + tumour cells) NK cells (natural killer)
