blood Flashcards
What is the average circulating volume in a typical adult male?
5L (IL in lungs, 3L in systemic venous circulation and 1 in heart and arterial circulation).
What are the 2 components of blood involved in clotting?
Prothrombin and fibrinogen.
What are the 6 main functions of blood?
Carriage of physiologically active compounds, clotting, defence, carriage of gas, thermoregulation and maintenance of ECF pH.
What is plasma composed of and what is its main function?
Composed of 95% water and proteins. Function is to circulate biologically active molecules and compounds.
What are the 3 sub-catagories of plasma proteins?
Albumin, globulins and fibrinogen/other clotting factors.
What are the main functions of albumin (80% plasma proteins)?
Transport of lipid/steroid hormones and helps create colloid oncotic pressure.
What do globulins do?
Gamma-globulins are antibodies. Alpha and beta transport lipids and fat-soluble vitamins.
What is colloid oncotic pressure?
Albumin creates colloid oncotic pressure. Plasma proteins do not readily cross the capillary wall. They displace water and create pressure than can pull water from the interstitial space into the lumen. This only changes volume, not concentration. Colloid oncotic pressure is 25mmHg and pulls water INTO the circulatory system.
What is capillary hydrostatic pressure?
BP. The pressure that the volume of blood in the circulatory system exerts on the walls of the blood vessels that contain it. This is dominant over COP and pulls fluid OUT OF the blood vessel.
What is the function of RBC’s?
Carry O2 around the body via haemoglobin. Flexible, bi-concave and non-nucleated (mature).
What is the normal life-span and normal circulating level of a RBC?
120 days and 4-6 x 10^12/L.
What is the function of erythropoietin?
Controls and accelerates erythropoiesis (formation of RBC’s). Stimulates the transformation of pluripotent stem cells to erythroblasts.
Which cells secrete erythropoietin?
Peritubular capillary cells of the kidneys (mostly) and hepatocytes.
Which factors would increase secretion of erythropoietin?
If oxygen supply to the kidneys is reduced. This could be caused by: hypoxia, haemorrhage, anaemia or lung disease.
What are the 5 main types of WBC’s? Describe their functions.
Neutrophils, eosinophils, basophils, monocytes and lymphocytes. Neutrophils: phagocytic, bacterial infection, form NETS. Eosinophils: parasitic infection and allergy. Basophils: release histamine and heparin. Promote inflammation. Monocyte: largest, migrate to tissues and become macrophages. Lymphocytes: T and B.
What is the process of WBC formation?
Leukopoiesis. More complex than erythropoiesis and controlled by interleukins/growth stimulating factors.
What are the main functions of platelets?
They adhere to damaged capillary walls and exposed connective tissue to mediate blood clotting. They are fragments of megakaryocytes and are formed by thrombopoietin.
What is haemocrit?
The percentage of blood made of RBC’s. 40-54% in females and 37-47% in males usually.
When might the normal values of haemocrit change?
Living in high altitude can increase haemocrit as need more haemoglobin to bind lower concentration of O2.
What is blood viscosity?
Thickness of blood in comparison to water. Plasma is 1.8 x thicker and whole blood is 3-4 x thicker.
When might blood viscosity change?
With haemocrit, temperature and flow rate.
