Blood Flow p.248

Blood Pressure Is the force of blood against the blood vessels Not constant & is greater when ventricles contract Hypothalamus = part of brain that monitors blood pressure and can cause the arteries to constrict or dilate 2 parts: Systolic pressure (systole) pressure when ventricles contract higher number given first 2. Diastolic pressure (diastole) pressure when ventricles are relaxing

Blood pressure is measured along a brachial artery Measured with a sphygmomanometer 120/80 = normal

Capillary Tissue Fluid Exchange At the arteriole end: Blood pressure > osmotic pressure So, net fluid movement is from the capillaries into the interstitial (or tissue) fluid Cells take in O2, glucose, amino acids from tissue fluid

Blood pressure = osmotic pressure At the midpoint: Blood pressure = osmotic pressure So, nutrients & wastes move with the concentration gradient O2 moves into cells & CO2 moves out of cells At venuole end: Blood pressure < osmotic pressure So, net fluid movement is from interstitial tissue into the capillaries Brings CO2 & wastes into bloodstream NOTE: any excess fluid in the tissue cells drains into the lymphatic system