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what is blood regarded as and what does it contain

connective tissue containing plasma (55%), RBC (45%) and white blood cells and platelets - very small amount


components of plasma and percentages

- 90-92% water.
- 6-7% proteins
○ Albumin – colloid osmotic pressure
○ Globulin – enzymes, antibodies
○ Fibrinogen – polymerizes into fibrin during coagulation or clot formation
- 2-3%
○ Fats
○ Carbohydrates (glucose)
○ Electrolytes
- Bicarbonate (buffering action), calcium, chloride, magnesium, phosphorus, potassium, sodium
○ Gases (O2, CO2)
○ Chemical messengers - cytokines and hormones


structure and composition of red blood cells function and life-span

water 60% and haemoglobin 40%
biconcave disk (max SA)
no nucleus or organelles in mammals
stains eosinophilic
corry O2, CO2 H+ (buffering)
life-span 80d cat 100-120 d and humans 150 horses, cattle, sheep


what is the name for immature red blood cells what percentage of RBC, how long until mature and where mature

1% of RBC, develop and mature in red bone marrow
circulate for a day before maturing


structure of haemoglobin, what contain and where does O2 bind

2 alpha and 2 beta chanis
contain haem - porphyrin ring containing Fe2+
O2 binds to Fe by occupying the sixth coordination position
4N bonds 1 globin bone 1 O2 bond per haem unit
each haemoglobin has 4 haem units and can bind H+ for buffering


CO2 how get into blood, how transported in blood and how move out of RBC
and how does CO2 cross RBC plasma membrane

diffuses across endothelial cells into blood - most transported by RBC as bicarbonate ions due to high levels of carbonic anhydrases or combined with haemoglobin
Cl-HCO3 exchanger channel transports bicarbonate out of RBC promoting formation of more bicarbonate within RBC
debate on how
1) Classical membrane diffusion
2) Diffusion through pores – “gas channels”
1. Aquaporin (AQP1)
2. Rhesus pore


platelets what is the other word for them, structure and composition, life span

- Small, ovoid bodies
- Cytoplasmic pieces ‘budded off’ from megakaryocyte
- ~ 2 μm diameter, disc shaped
• Lifespan 8-10 days (sequestered in the spleen - can mobilize quickly)
Dense granules
-ADP, serotonin (a vasoconstrictor), calcium
• Alpha granules
- Thrombospondin, fibrinogen


function of platelets and how exert effects

blood clotting
aggregation - platelet adherence - associated with endothelial cells injury; formation of platelet plug
○ Coagulation - fibrin formation, initiated at larger sites of injury; formation of a clot (thrombus)
○ 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
- These lead to the formation of a fibrin seal on the deposited platelets which plugs the leak


and what are haemopoetic stem cells

production of new RBC
multipotent - can form any blood cell line, they are present throughout life


what is needed to differentiate into red blood cells what produced by, where and what does it do

produced by fibroblast-like cells in cortex and outer medulla of kidney
- Shortens cell cycle time
- Increased rate of maturation
- Increased rate of release from bone marrow
• Increased presence of circulating reticulocytes when erythropoietin is active
- Indicative of recent increase in erythropoiesis


what is the role of haemopoiesis

To maintain homeostasis:
- Short lifespan of mature blood cells requires continual replacement throughout life
• Enable a rapid response to life-threatening conditions :
- Blood loss - RBC numbers are tightly regulated
- Infection - WBC numbers increase to fight infection
• Remove and replace dangerous cell types:
- Neutrophils and eosinophils - Once activated they are damaging to surrounding tissues


where does haemopoiesis occur

- yolk sac, liver & spleen
• Foetus:
- liver, spleen & bone marrow
• After birth
- bone marrow
• Juvenile: long bones & flat bones (pelvic bones & vertebrae)
• Adult: flat bones - pelvis & ends of long bones


regulation of Haemopoiesis

involves differentiation of HSC
in bone marrow interact with:
- Stromal fibroblasts
- Osteoblasts
- Endothelial cells
- Extra-cellular matrix
receptors on HSC bind to
- Stromal adhesion molecules
- Membrane bound stromal growth factors
- Soluble growth factors
- Extra-cellular matrix
which all control gene expression and directs development


list steps in what occurs after large blood loss

1) Fall in circulating RBC mass
2) Tissue hypoxia - lack of oxygen
3) Stimulates EPO production by renal peritubular cells
4) EPO occupies specific receptor sites on progenitor cell membranes
5) Resulting in
- shortened cell cycle time
- Increased rate of maturation
- Increased rate of release of RBC from bone marrow
6) Increased red cell mass and increased delivery of O2 to tissues, removing stimulus for EPO synthesis and erythropoiesis returns to normal


where is adaptive immunity found

vertebrates only


functions of mast cells and basophils, eosinophils

mast cells and basophils - release factors which increase blood flow and vascular permeability
eosinophils - secrete factors which kill protozoa and worms


name a type of protein involved in innate immunity, where found and its function

Acute phase proteins (C-reactive protein, mannan binding protein) - found in the liver - activate complement and opsonise pathogens


two broad types of leukocytes and sub types within

1) Granulocytes
1. Neutrophils
2. Eosinophils
3. Basophils
2) Agranulocytes
1. Lymphocytes
2. Monocytes


percentage of leukocytes in the blood for sheep

Neutrophils - 30%
Eosinophils - 5%
Basophils 0.5%
Lymphocytes 62%
Monocytes 2.5%


list the 3 killing mechanisms of neutrophils

1) Phagocytosis
2) Degranulation - primary azurophilic and secondary specific granules
3) NETs - neutrophil extracellular traps - entrap the pathogen with molecules secreted from the neutrophil


functions of basophil function

- Major role in allergic and inflammatory reactions
- Surface receptors for IgE
- Limited phagocytic and bactericidal activity
- Predominant source of IL-4 and IL-13 in allergic disease


mast cell functions within the gastrointestinal tract, airways and blood vessels

Gastrointestinal tract - important for parasites and worms
Airways - decreased diameter - prevent more pathogens from entering and increased mucus secretion - entrap the microbes
Blood vessels - as mast cells degranulate increase permeability of the blood - if get systemic infection can cause anaphylactic shock as too much leakage through blood vessels throughout body causing a decrease in blood volume and pressure


eosinophil function

Major role in controlling parasitic infestation
Possible roles against bacterial and viral
tissue remodeling


examples of mediators produced by mast cells and basophils and eosinophils

histamine - increase vascular permeability
prostaglandin - vasodilation
cytokines - IL-3,4,5 - mast cell proliferation - inflammation
peroxidase, hydrolases - degrades helminithic and protozoan cell walls
leukotrienes - increase vascular permeability


monocytes what do they do

reach functional maturity after leaving bloodstream and become macrophages


functions of macrophages

➣ Antigen presenting cells (APC) – initiate immune response
➣ Highly phagocytic
• Ingest and kill microbes - PAMPS
• Clearance of RBC, WBC, apoptotic cells - DAMPS - damaged cells
➣ Produce cytokines – signalling and amplification of immune response
➣ Produce colony stimulating factors – haematopoiesis


dendritic cells function and where found

activate T cells found in small quantities in tissues that are in contact with external environment - skin and intestines


where are B cells derived in mammals, birds, and ruminants

bone marrow
bursa of fabricuis
ileal peyers patches


list different classes of antibodies what structure and function

1) IgM - µ - pentamer - best at fixing complement and the monomer severs as the B cell receptor
2) IgG - ƴ - monomer - highest percentage of total antibody in serum - neutralises toxins and opsonisation
3) IgA - α - dimer - has secretory component, can cross gut membrane, secreted into mucus, tears, saliva and colostrum
4) IgE - Ɛ - monomer - binds to mast cells and basophils - antibody of allergy and ant parasitic activity
5) IgD - δ - monomer - can be a B cell receptor


functions of natural killer cells

1) killing injured cells
2) killing infected cells
3) killing phagocytosed microbes