1.2 Haematopoiesis and blood cells Flashcards
Main components of blood:
- maintain homeostasis
- transport system
- facilitate endocrine signaling
- transport gases
- maintain integrity of vascular system
- immunity and infection control
Liquid phase of blood:
- wbc (infection control)
- rbc (oxygen)
- platelets
Prevents clotting:
Anti-coagulant
Buffy coat =
wbc and platelets
Packed cells =
rbc
Serum =
Plasma without clotting factors
Blood sample without anti-coagulant:
Blood sample with anti-coagulant:
Total body water =
60% of body weight
- ICF 40%
- ECF 20%
ECF:
Interstitial fluid (IF) : 80% of ECF
Plasma: 20% ECF
Milk fever and grass stagger are caused by?
- Hypocalcemia (Ca in blood deficiency)
- Hypomagnesium ( magnesium in blood deficiency)
Plasma proteins: (6)
Albumin, globulins, antibody, carrier proteins, hormones, cytokines
Where are your antibodies found?
Gamma globulins
Albumin:
Colloidal osmotic pressure in blood
- high pressure force fluid out of tissues
Immunoglobulin (antibody):
- produced in lymphoid tissue
- circulate in the blood to the tissues
- immunological defense system
Nutrient products of metabolism:
- glucose
- amino acids
- lipids / fatty acid
- Vitamins (micronutrients)
Waste products of metabolism:
- urea (nitrogenous waste)
- ketones
Hematopoiesis:
Blood cell formation
- starts in yolk sac
- shifts to fetal liver me spleen into utero
- bone marrow post-partum
Main blood cell production system:
Hematopoiesis
Is a major Hematopotic organ?
Bone marrow
What does the bone marrow produce?
Production of RBCs, WBCs & platelets from precursor stem cells
Erythroprotein (EPO)
Hormone that increases production of rbc through kidneys
__ and __ tel the bone marrow how many wbc’s to produce
Hormone and cytokines
Granulocyte-macrophage colony stimulating factor (GM-CSF) is produced by
- activated macrophages and regulates the number of WBCs produced
- During infection the bone marrow is ordered to increase supplies of frontline troops.
Red blood cell appearance:
- Biconcave discs with high surface area : volume ratio
Rbc in mammals:
Lack nucleus and mitochondria / organelles in mammals
Rbcs in birds and reptiles =
Nucleated rbcs
Hemoglobin:
- Two alpha and beta protein chains
- Haem group contains iron (Fe) ×4
- Gaseous exchange: (Carries O2 from lungs to tissues
Why is carbon monoxide so dangerous?
Carbon monoxide binds irreversibly to haem blocking O2 transport
- O2 can no longer be carried
Erythrocyte lineage
-Synthesis of haemoglobin
-Shutdown of cellular function
- Ejection of nucleus
- Contraction to small biconcaved shape
Red blood cell turnover:
Once past cell life date they are removed by liver and spleen
Haemoglobin turnover
Jaundice = increase in
Bilirubin
Jaundice: pre-hepatic
Increased rbc destruction
Jaundice: hepatic
Liver disease
Jaundice: post-hepatic
Biliary stasis / blockage
Increased PCV / Harmatocrit can be caused by?
Dehydration
– Reduced circulating volume (plasma
Polycythemia vera
– Often from tumour in Bone marrow
or kidney (EPO)
Reduced PCV =
Anaemia
Regenerative anaemia
– Increased RBC loss (haemorrhage)
– Increased RBC destruction (haemolysis)
Non-regenerative anaemia
– Decreased RBC production
• Bone marrow disease
• Systemic disease impacting on BM function
Regenerative anaemia: Evidence of bone marrow response to RBC deficiency
Immature RBCs are released prematurely
– Bigger than normal
– Less Hb than normal
– May still have organelles (reticulocytes)
– May still have nucleus/remnant (normoblast)
**may differ in size and color
Feline regenerative anaemia: Mycoplasma hemofelis
Regenerative anemia
Feline Non-regenerative anaemia: Chronic renal failure
Platelets (thrombocytes) are produced by?
Produced from megakaryocytes in the bone marrow by cytoplasmic budding
Haemostasis
- Platelets adhere to damaged endothelium to form a ‘platelet plug’
- Activated platelets release vasoactive mediators (e.g. serotonin)
- Release of clotting factors – Fibrinogen > Fibrin
Thrombocytopenia
- antibodies attack platelets
- Consumption of platelets during haemorrhage
- Increased destruction (immune-mediated)
- Reduced production (BM defect)
- Clotting disorder
White blood cells (leucocytes)
- Neutrophils ( most common)
- Eosinophils
- Basophils ( least common)
- Monocytes
- Lymphocytes
Neutrophil
- Major role in acute inflammation and bacterial infection
- Granulocytes with a multilobed nucleus
- Various granules containing anti-microbial factors
Eosinophil:
- typically seen in helminth infections and allergy
– Pro-inflammatory cytokines - Granulocytes that stain red with eosin dye
Basophil
Relatively rare WBCs
- Granules contain:
– Histamine
– Proteases (e.g. chymase, tryptase)
– Pro-inflammatory cytokines
– Chemokines
Tissue mast cell:
- Similar to basophil but resident in tissues
- Express receptors for IgE
- Degranulate to release histamine, proteases and inflammatory cytokines/chemokines
- Important cells for parasite defence and also involved in allergic inflammation
Monocyte
- immature cell
- Travels from bone marrow to tissues
- Exits blood and differentiates into macrophage or dendritic cell (see later)
Lymphocyte:
- Small cells with round nucleus and little cytoplasm
– T cells = cell-mediated immunity
– B cells = antibody-mediated immunity
**Lymphopenia is part of ‘stress leukogram’ and also seen in acute viral infection
