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 Alternating expansion and recoil of a blood vessel wall (the pressure wave) that occurs as the heart beats  Locate arterial pulse at “pressure points” in superficial arteries  These same points are used to stop blood flow due to hemorrhage from injury  Avg is bpm at rest for a healthy person © 2015 Pearson Education, Inc.

Superficial temporal artery Facial artery Common carotid artery Brachial artery Radial artery Femoral artery Popliteal artery Posterior tibial artery Dorsalis pedis artery

 Blood pressure is: the pressure the blood exerts against the inner walls of the blood vessels  Blood is forced along a descending pressure gradient ◦ Pressure is highest in the large systemic arteries, lower in the capillaries, and lowest in the veins  Elasticity of vessels is pertinent to healthy, elastic arteries © 2015 Pearson Education, Inc.

Figure Blood pressure in various areas of the cardiovascular system. Systolic pressure Diastolic pressure –10 Pressure (mm Hg) Aorta Arteries Arterioles Capillaries Venules Veins Venae cavae

 Systolic—pressure at the peak of ventricular contraction  Diastolic—pressure when ventricles relax  Expressed as systolic over diastolic ◦ 120/80 mm Hg is average ◦ The brachial artery is used for measurement  Hypotension- low blood pressure (<100 sys.)  Hypertension- high blood pressure (>140/90) © 2015 Pearson Education, Inc.

1. Resistance within blood vessels (increases) 2. Kidneys regulate blood volume via enzymes 3. Temperature- 1.cold causes vasoconstriction 2.Heat causes vasodilation 4. Chemicals 1.Hormones like epinephrine 2.Drugs/nicotine 3.Diet © 2015 Pearson Education, Inc.

 Gas and nutrient exchange occurs through capillary walls ◦ Driven by concentration gradients  Oxygen and nutrients go from blood to tissues  Carbon dioxide and other wastes go from tissue to blood  Substances diffuse through the interstitial fluid (tissue fluid) found between cells © 2015 Pearson Education, Inc.

1. Direct diffusion through membranes 2. Diffusion through intercellular clefts/gaps 3. Diffusion through pores 4. Transport via vesicles (bulk transport) © 2015 Pearson Education, Inc.

Direct diffusion through membrane 1 Diffusion through intercellular cleft/gap 2 Diffusion through pore 3 Transport via vesicles 4 Interstitial fluid Lumen of capillary Vesicles Intercellular cleft pore

 Blood pressure forces fluid and solutes out of capillaries at the arterial end  Osmotic pressure draws fluid into capillaries at the venous end  At the arterial end, BP > OP  At the venous end, BP < OP © 2015 Pearson Education, Inc.

Tissue cellInterstitial fluid Net fluid movement out Net fluid movement in Arterial end of capillary Venule end of capillary Blood pressure is higher than osmotic pressure At the venule end of the capillary, blood pressure is less than osmotic pressure, and fluid flows from the interstitial fluid into the capillary. Blood pressure is lower than osmotic pressure Osmotic pressure remains steady in capillary bed At the arterial end of a capillary, blood pressure is more than osmotic pressure, and fluid flows out of the capillary and into the interstitial fluid.