Blood Flashcards
What is the average circulating volume of an adult male
5L of blood
1L in lungs
3L in systemic venous circulation
1L in heart and arterial circulation
What is the function of blood
- Carriage of physiologically active compounds (plasma)
- Clotting (platelets)
- Defence (WBC)
- Carriage of gas (RBC)
- Thermoregulation
- Maintenance of ECM pH
What is the composition of plasma
- Is 4% of body weight
- Is 95% water
- Makes up 50% of blood
What are the plasma proteins
- Albumin
- Globulin - alpha, beta, gamma globulins
- Fibrinogen and other clotting factors
What is colloid oncotic pressure
- Plasma proteins in vessel cause low water concentraion
- Water from ICF diffuse into plasma
- Capillary hydrostatic pressure favours movement out of capillary
Result - concentration of fluid is unchanged volumes are altered, ICF has 3x-4x volume
What is the normal lifespan of RBC and platelets
RBC - 120 days
Platelets - 10 days
What is the funtion of RBC
Densely packed with haemoglobin
Highly flexible
Bioconcave
No nucleus
7-8 micrometer
What is erythropoiesis
RBC formation
Controlled and accelerated by hormone erythropoietin
What does erythropoietin do
Stimulates maturation process of pluripotent stem cells to erythroblasts (immature RBC)
Describe secretion of erythroproteins
Secretion - kidney (85%), liver (15%)
Secretion increased when O2 delivery to kidneys is low
What are the 5 main types of WBC
Granulocytes - Neutrophils, Eosinophils, Basophils
Argranulocytes - Monocytes, Lymphocytes
What is the differences between monocytes and macrophages
Monocytes - Circulate in body up to 72hrs
Macrophages - Myocytes that migrated to CT and live for 3 months
What controls WBC formation
Controlled by cytokines
Colony stimulation factors - Granulocyte CSF
Interlukeukins
Describe cytokines
Released from mature WBC
Stimulates mitosis and maturation of leukocytes
What stimulates leukopoiesis
Bacterial infection - increase neutrophils
Viral infection - increase lymphocytes
What are platelets
Membrane bound cell fragments
Rarely nucleated
2-4 micrometers
What is the role of thrombopoientin
Governs formation of platelets
What is the function of platelets
Adhere to damaged vessel walls and exposed CT to mediate blood clotting
What is Haematocrit
The % of RBC to whole blood
Normal range 40-50% , changes (hydration and elevation)
What is blood viscosity
How thick/sticky blood is compared to water
How does viscosity change
Haematocrit - 50% increase, increases viscosity by approx 100%
Temperature - Increase in temp decreases viscosity, vise versa. 1oC changes viscosity by around 2%
Flow rate - descrease flow rate increase viscosity and vise versa
