Lecture 7 Blood Homeostasis & Components Flashcards
What are the functions of blood (3)
- Distribution
- oxygen & nutrients
- carbon dioxide & waste - Regulation
- body temperature
- pH
- fluid volume - Protection
- against haemorrhage (fibrinogen)
- against infection (leukocytes/white blood cells)
What percentage of the total body mass is blood?
8% (5 litres)
Components of plasma
- blood is made up of 55% plasma
- Proteins 7% :Albumins 54%, Globulins 38%, Fibrinogen 7%, all others 1%
- Water 91.5%
- Other solutes 1.5%
Electrolytes, nutrients, gases, regulatory substances, vitamins, waste products
Formed elements of the blood
- make up 45% of the blood
- Platelets (150,000-400,000)
- White blood cells (5,000-10,000)
- Red blood cells (4.8-5.4 billion)
Components of blood with anticoagulant
-plasma (55%)
-buffy coat, composed of white blood cells & platelets
- red blood cells (45%)
Components of blood without anticoagulant
- serum (fibrogen depleted)
- buffy coat/layer
- clot (red blood cells & fibrins)
What are the 3 formed elements?
- Erythrocytes = red blood cells
- Leukocytes = white blood cells
- Thrombocytes = platelets
What are the percentages of different types of white blood cells in the blood? (5)
- Neutrophils 60-70%
- Lymphocytes 20-25%
- Monocytes 3-8%
- Eosinophils 2-4%
- Basophils 0.5-1.0%
What is haemopoiesis?
The production of blood cells
What is eosin stain?
Stains basic/alkali components red
(E.g. proteins - eosinophil - basic protein)
What does methylene blue stain?
Stains acidic components blue
(E.g. DNA)
What is Wrights’s stain?
Eosin + methylene blue
What do blood cells differentiate from
Pluripotent stem cell
What is erythropoietin’s & where does it occur ?
- The formation of red blood cells
- Occurs in the red bone marrow
What is erythropoietin ?
It stimulates erythrocyte formation and is produced in kidney
Features of Erythrocytes (RBCs) (6)
- Anuclear (no nucleus)
- Biconcave shape
- Contains haemoglobin (33% of weight)
- Oxygen transport/ carbon dioxide removal
- Make 2 million per second
- Last approx. 120 days
What is the Stain characteristic of Basophils ?
- Bilobed nucleus
- blue granules (histamine)
What are the stain characteristics of Eosinophils ?
- Bilobed nucleus
- Red granules (basic protein)
What are the stain characteristics of Neutrophils?
- multi-lobed nucleus
- few granules
What are the stain characteristics of monocytes?
- Horseshoe shaped nucleus
- large cells
What are the stain characteristics of platelets ?
- Not cells
- No nucleus, small
What are the 2 categories of leukocytes & what are the function of leukocytes?
- Granulocytes - granules in cytoplasm
- Agranulocytes - no granules in cytoplasm
Function: protection
Name the 3 Granulocytes & their functions?
- Neutrophils - phagocytes (engulf pathogens)- move to site of infection
- Eosinophils - allergic response & parasitic invasion
- Basophils - allergic, inflammatory response & parasite invasion
(release histamine during inflammation)
Name the Agranulocytes & describe their functions?
- Lymphocytes - immune response
- T-lymphocytes
- B-lymphocytes ( differentiated in plasma cells that produce antibodies) - Monocytes - differentiate into macrophages
Phagocytes & can recruit other elements of immune system
What are platelets ?
- contain clotting/coagulation factors
- They are cytoplasm of Megakaryocyte pinched off to produce platelets
- 2-3 micrometers in diameter
What is Haemostasis?
Refers to sequence of responses to stop bleeding
If unsuccessful can lead to haemorrhage
What are the 3 main stages that Haemostasis stops bleeding?
- Vascular spasm (circular smooth muscle in damaged artery walls start to contract)
- Platelet plug
- Blood clot formation - where Fibrinogen (soluble) is converted to Fibrin (insoluble threads)
Platelet plug formation
1.Initially platelets contact and stick to part of damaged blood vessel such as connective tissue (collagen) underlying damaged endothelial cells ( platelet adhesion)
2. Due to adhesion platelets become activated and start to release contents of vesicles which are coagulation factors
3. More platelets stick activated platelets and form mass of platelets known as platelet plug
- capillary endothelial cells
Blood clot formation
Thrombin converts soluble fibrinogen to insoluble threads of fibrin
Platelets have projections when activated which help to capture fibrin threads in them
Tissue fluid & nutrient exchange (3)
- water, glucose, amino acids, mineral salts, oxygen filtered out of the blood capillary at arterial end due to high hydrostatic pressure caused by contraction of heart
- Blood cells, platelets & plasma proteins remain in blood capillary
- Carbon dioxide and other waste reabsorbed from tissue into venous end of capillary
What 2 forces are involved in the formation of tissue fluids and dictate Filtration Pressure?
- Hydrostatic pressure (pushing)
- Osmotic pressure (pulling)
Net FP = net hydrostatic pressure - net osmotic pressure
What is the approx net litres of tissue fluid per day? (3)
-20 litres per day from blood stream into tissue
- 17 litres from tissue into blood stream
- The other 3 litres turn into lymph
Filtration pressure in formation of tissue fluid? (3)
- Proteins & ions give the blood a relatively high osmotic pressure (likely to drag water into blood)
- At the arterial end of the capillary the hydrostatic pressure (3.7 kPa) overcomes this osmotic pressure (2.0kPa) & fluid( along with nutrients & gases) moves into the tissue
- At the venous end of the capillary, the hydrostatic pressure is reduced but the osmotic pressure is the same ( as cells/protein levels are the same in blood) this drags fluid back into the blood
What does filtration pressure determine?
Overall movement of fluid
What happens to filtration pressure at arterial end?
FP is positive
Fluid passes from the blood to the tissue fluid
What happens to filtration pressure at the venous end?
FP is negative
Fluid passes from the tissue fluid to the blood
What is the relationship between lymph & blood vessels (tissue fluid) ? (3)
- Lymph accounts for the 3 litres of fluid not reabsorbed
- Lymphatic vessels transport lymph from tissue spaces to veins
- Lymph drains into the circulatory system via lymphatic ducts located in veins near the heart
List 3 clinical blood abnormalities
- sickle cell disease (SCD)
- septicaemia
- haemophilia
