Introduction to Blood Flashcards
Know the average circulating volume in a typical adult male.
5 litres; 1L in lungs, 3L in systemic venous circulation, 1L in heart and arterial circulation
List the functions of blood.
Components of blood:
1. Carriage of physiologically active compounds (in plasma)
2. Clotting (platelets form scaffolding where the clot can form)
3. Defence (white blood cells)
4. Carriage of gas (e.g. red blood cells carry O2 and CO2)
Whole blood:
5. Thermoregulation
6. Maintenance of ECF pH
Describe the composition of plasma.
Antibodies, clotting factors, and the proteins albumin and fibrinogen.
Name the plasma proteins .
Plasma proteins subdivided into 3 categories:
1)Albumin
2) Globulin - Subdivided into α, ß, γ globulins
3)Fibrinogen and other clotting factors
NOTE: Plasma proteins are not taken up by cells - perform their functions in the circulation. Compare with organic compounds e.g. hormones which use blood as a vehicle.
Define the term oncotic pressure and describe the factors responsible for generation.
Oncotic pressure is the osmotic pressure generated by large molecules (especially proteins) in solution. Net direction of movement is determined by balance between colloid oncotic pressure (favours movement into capillary) and capillary hydrostatic pressure (blood pressure) which favours movement out of capillary.
Presence of plasma proteins pulls the water into the plasma therefore more ions pulled in and so glucose is pulled in. Counteracted by blood pressure, increased this = counteracts whats above.
Know the normal lifespan of red blood cell and platelets in the circulation.
Red blood cells = 120 day lifespan.
Platelets = 10 days lifespan.
Describe the function of the red blood cell.
Absorb oxygen and carry it, can do this due to their biconcave shape
Describe the function of erythropoietin, where it is synthesised and the factors which
may increase secretion.
Red blood cell formation is controlled and accelerated by hormone erythropoietin. Secretion enhanced when oxygen delivery to
kidneys is reduced (hypoxia) e.g. haemorrhage, anaemia. Produced predominantly by specialised cells called interstitial cells in the kidney.
Name the five main types of white blood cells.
- neutrophils.
- monocytes.
- eosinophils.
- basophils.
- lymphocytes.
Appreciate the difference between a monocyte and a macrophage.
Macrophage - outwith circulation
Monocyte - circulating cells
Have an understanding of the factors controlling white blood cell formation.
Controlled by a cocktail of cytokines (proteins/peptides released from one cell type which act on another). Colony Stimulating Factors and Interleukins
Be able to classify the different types of blood cells.
Erythrocytes (red blood cells) , white blood cells (leukocytes) and platelets.
Know the unique function of platelets.
Adhere to damaged vessel walls and exposed connective tissue to mediate blood clotting. DO NOT adhere to healthy intact endothelium.
Outline the role of thrombopoietin in platelet formation.
Upon binding of thrombopoietin to the transmembrane region, the receptor conformation changes and a number of signal transduction pathways are activated that increase platelet production.
Define what is meant by haematocrit.
Hematocrit is the percentage by volume of red cells in your blood.
