Blood Avian Physiology Function of Blood - Transport Oxygen, - PowerPoint PPT Presentation

Blood Avian Physiology

Function of Blood - Transport • Oxygen, • CO 2 • Nutrients - glucose, amino-acids, lipids, lactate • Water • Waste - uric acid/urates • Heat – body temperature • Hormones • Immune protection • Osmotic balance/ minerals

Components of blood • Plasma – 60-70% of blood • Cells/corpuscles – 30-40% of blood – Hematocrit = 30-50

Hematocrit • Hematocrit = Packed Cell Volume (PCV) after centrifugation of whole blood

Components of Plasma • 90% water • 10% solutes – Minerals - Na, K, Ca, Mg, HCO 3, Cl, Phosphate – Nitrogenous Compounds: • Proteins – 3-6 g/dl • non-protein nitrogen (uric acid, urate) – Nutrients - glucose 150-250 mg/dl (fasting) – Lipids - free fatty acids, neutral fats, phospholipids, cholesterol esters – Yolk precursors + Hormones

Centrifuge blood with an anticoagulant (prevents clotting) to separate plasma from cells. Prior to After Centrifugation Centrifugation Plasma Buffy coat = WBC Corpuscles Red Blood Cells

Plasma proteins • Albumins –greatest, 40% of total plasma protein – Transport other substances (hormones) – Osmolality of blood and Egg formation • Clotting proteins= fibrinogen, pro-thrombin • Globulins – α and β globulins are transporters – γ globulins are antibodies • Hormones • Lipoproteins, i.e. yolk proteins • Glycoproteins • Hemoglobin • Enzymes

Clotting Proteins and Clotting • Clotting should not occur unless injury • Initiated by Prothrombin activating factors , ie Thromboplastin • Factors that cause release of thromboplastin: – Extrinsic Factors = external trauma that damages vessels – Intrinsic Factors = damage of blood cells • Fast uncontrolled once started

Clotting Proteins and Clotting • Cascade:  Prothrombin activating factors  Thrombin Prothrombin (an α globulin)  Fibrinogen   Fibrin threads + Ca ++ + fibrin stabilizing factor = Polymerization and clotting

Clotting Time • Whole chicken blood clots in 2 – 120 min. • Prothrombin time is more sensitive: – Add Ca chelator – sodium citrate or Ca precipitator – sodium oxalate ( anticoagulants ) to prevent blood from clotting prior to test. – Separate cells from plasma by centrifugation – Add excess of Ca and known amount of prothrombin to plasma – Record time required for clot formation.

Prothrombin Time • Chicken prothrombin time is 10-20 sec with 12 sec average. • Vit. K is needed for synthesis of many procoagulation factors – ↓ Vit. K in diet and blood = ↑ Prothrombin time – Prothrombin time is an accepted bioassay for Vit. K levels in chickens.

What prevents blood from clotting in the circulatory system, since everything is in there that is needed for clotting? • Natural anticoagulants = heparin • Roughed surface is needed for clot formation • No injured vessel then intravascular clotting is rare.