Blood Cell Formation and Function Flashcards
What is the intracellular substance of blood?
Plasma
What is the cellular substances of blood?
RBC - erythrocytes WBC - Leukocytes Platelets - derived from cells that are no longer cellular
What is plasma?
-Rich in protein - albumin, globulins, Ig, fibrinogen = clotting -Regulatory substances, nutritional substances, salts, waste - Removal of fibrinogen-fibrin - serum
What percentage of blood is made up of plasma?
~55%
What percentage of blood is RBC?
~45%
What is the purpose of plasma in the blood?
-Transport mechanism
What is the biggest component that makes up blood?
90-92% water 6-7% proteins 2-3% fats, carbs, electrolytes, gases, chemical messengers
What are the two categories of blood cells?
1) Red blood cells = erythrocytes 2) White blood cells = leukocytes
Are there more red or white blood cells found in blood usually?
Red, but the exact number varies in an individual
What are the 2 main components that make up erythrocytes?
water = 60% Haemaglobin = 40%
True or false mammalian RBC have no nucleus
True - except when foetus (lose after birth)
What colour do RBC stain?
Eosinophilic
What are the functions of RBC?
Carrying O2, CO2 and H+ around the body - buffering role
What are reticulocytes?
They are immature red blood cells - make up ~1% of red cells in the human body
how long do reticulocytes circulate before they develop into mature RBC?
About 1 day
Who’s RBC is this?
Avian
Who’s RBC is this?
Sheep
Who’s RBC is this?
Camel
Do we know why mammalian RBC lose their organelles?
No
What are the groups that carrying the oxygen in RBC?
Haem - made up of 4 subunits that can each carry 2 O2 so lots of carrying potential
How is CO2 carried in blood?
CO2 diffuses across endothelial cells into blood (driven by high CO2 levels in tissues) - most is transported by the RBC as bicarbonate ions (64%) or combined with haemoglobin (21%) or dissolved in erythrocytes (4%) - Plasma only carries a bit 6% dissolved and 5% converted into bicarbonate ions
What are thrombocytes?
Platelets
What is the arrow pointing to?
Platelets
What are thrombocytes involved in?
Essential for haemostasis = clotting
Where are platelets from?
Megakaryocytes = bud off from Resevoir in spleen
What is the lifespan of platelets?
8-10 days
What is the structure and composition of platelets?
-small, ovoid bodies - granules
What are the 2 types of blood clotting thrombocytes are involved in?
1) aggregation: platelet adherence - epi cell injury = platelet plug 2) Coagulation: fibrin formation - larger site wounds
What are the steps to blood coagulation?
injury triggers two events: 1) the activation and deposition of platelets at a wound site 2) Activation of coagulation pathway: - prothrombin converted to thrombin - thrombin causes fibrinogen to polymerize into fibrin 3) lead to the formation of a fibrin seal on the deposited platelets 4) “plugs the leak”
What is a differential cell count?
Morphological examination = general health of the animal
What does haematocrit (Hct) measure?
Packed cell volume (PCV)
What factors could change plasma levels?
-Dehydration = make haematocrit appear larger than it is - mask anaemia - increase in pregnancy can mimic anaemia
How long do RBC last in the body?
100-120 Days Highest cells produced rate as well as longest lifespan
What does Multipotent Stem cell mean?
They can form any blood cell line -myeloid and lymphoid
How do multipotent stem cells differentiate?
-controlled by lineage-independent and lineage-specific cytokines and grown factors
What is the role of haemopoiesis?
1) to maintain homeostasis 2) enable a rapid response to life-threatening conditions: - blood loss (RBC numbers are tightly regulated) - Infection (WBC numbers increase to fight infection) 3) Remove and replace dangerous cell types: - Neutrophils and Eosinophils
Where is the site of haemopoiesis in Adult animals?
- Bone marrow = proximal ends of femurs, pelvic flat bones, vertebrae, skull, ribs and sternum
What regulates haemopoietic stem cells?
Lots happening but the receptor binding controls gene expression and directs the development Differentiation triggered by: depends on signal molecules
What triggers Erythropoiesis?
Hypoxia
What controls Erythropoiesis?
Erythropoietin that is produced by fibroblast-like cells in the cortex and outer medulla of the kidney
How does EPO control Erythropoietin?
-Shortens the cell cycle time -increases the rate of maturation -Increased rate of release from bone marrow = increases presence of circulating reticulocytes
what is a indication of recent increase in erythropoiesis?
Increased presence of circulating reticulocytes
Where is erythropoietins made?
Kidneys!
What is Anaemia?
A disease of erythrocytes: reduction in the ability of blood to carry oxygen = too few RBC or low haemoglobin levels in RBC
What is Polycythaemia?
Disease of erythrocytes: excessive number of RBC = bone marrow cancer or moving in high altitudes
