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

Blood

Avian Physiology

Function of Blood - Transport

• Oxygen,
• CO2
• 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, HCO3, 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 Centrifugation After Centrifugation Plasma Red Blood Cells Buffy coat = WBC

Corpuscles

Plasma proteins

• Albumins

–greatest, 40% of total plasma protein – Transport other substances (hormones) – Osmolality

• f 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 Prothrombin  Thrombin

(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.