PHSL232 Lecture Notes - Lecture 9: Capillary Pressure, Blood Vessel, Flow Velocity
Document Summary
Understand the functional anatomy of the microcirculation: more than one design. Understand the balance of fluid exchange through the capillary wall; role of the lymphatic system. Understand the blood reservoir function of the veins. Primary function of capillaries is the exchange of nutrients and metabolic products: Water is driven across capillary wall by a balance between: hydrostatic (perfusion) pressure moves water out of the capillary, colloid osmotic pressure generated by plasma proteins dissolved in the plasma: draws water into the capillary. Nb: lymphatics drain excess fluid from isf back into systemic circulation. Small changes in capillary pressure can alter the amount of water shifting in or out of the capillaries. A major determinant of capillary pressure is the amount of resistance n the small arterioles up stream. Some capillary beds are designed : a) for net filtration: highly efficient lymph absorption (lungs) Veins are low resistance, high capacitance vessels = high compliance.
