W ARM -U P 1. What is the pacemaker? Where is it located? 2. List the parts of the intrinsic conduction system of the heart. 3. Draw and label the 3 waves of a typical EKG tracing. What is happening at each wave? 4. What causes the heart sounds (lub-dub)?

W ARM -U P 1. Compare arteries, capillaries, & veins. 1. Imagine you are a red blood cell. List the pathway you would travel through the body in a complete circuit starting at a pinky toe. 2. Explain how blood pressure is measured.

W ARM -U P 1. What is hypertension? What are possible causes? 2. What is atherosclerosis? 3. What can you do to prevent atherosclerosis? 4. What treatment options are available for patients with coronary atherosclerosis?

B LOOD V ESSELS & C IRCULATION

Vascular System: blood circulates inside closed transport systems Types of Blood Vessels: Arteries (takes blood away from heart) Arterioles Capillary beds Venules Veins (return blood back to heart)

A NATOMY OF B LOOD V ESSELS Three coats (tunics): 1. Tunica intima: endothelium lines the interior of vessels; decreases friction as blood flows 2. Tunica media: smooth muscle & elastic tissue (dilates & constricts vessels) 3. Tunica externa: fibrous connective tissue on outside supports and protects vessels

Arteries Capillaries Veins Blood away from heart Thicker walls Withstand high pressure Walls 1-cell thick Exchange gases between blood and tissue cells Blood back to heart Thinner walls Low pressure Large lumen Valves Valves: prevent blood backflow Skeletal muscles enhance venous return

V ERICOSE V EINS People stand for long periods of time  inactivity or pressure on veins Blood pools in feet and legs Valves weaken  veins become twisted & dilated Treatment: compression stockings, exercise, laser treatment, surgery

V ITAL S IGNS Pulse: expansion & recoil of an artery with each beat of left ventricle Pressure points (eg. carotid artery, radial artery) Normal resting: beats/min

V ITAL S IGNS Blood pressure: pressure of blood on inner walls of blood vessels Systolic presure: peak of ventricular contraction Diastolic pressure: ventricles relaxed Written: Systolic/Diastolic Normal: (120 mm Hg)/(70 mm Hg) or 120/70

M EASURING B LOOD P RESSURE

U SING A SPHYGMOMANOMETER Wrap cuff around upper arm Place stethoscope on brachial artery Inflate cuff to 180 mm Hg Slowly release air  listen for whooshing sounds in brachial artery ( Korotkoff sounds ) Systolic: when sound begin to appear Diastolic: when sounds disappear

YouTube: How to Measure Blood Pressure

H OMEOSTATIC I MBALANCES Hypertension: high blood pressure (>140/90) Circulatory shock: acute hypotension Blood loss Atherosclerosis – artery walls thicken due to fatty deposits (plaques)

S TENT VS. B YPASS S URGERY

C ONGESTIVE H EART F AILURE Progressive weakening of heart Low heart efficiency  circulation inadequate to meet tissue needs Caused by: Coronary atherosclerosis Persistent high blood pressure Multiple heart attacks – scar tissue