Circulatory System Take a look at a skeleton and see how well a heart is protected — open heart surgery takes breaking a body to get to the heart. 2008-2009

Feeding Energy Needs Why do we need a circulatory system?

Blood & blood cells Blood is a tissue of fluid & cells plasma cells liquid part of blood dissolved salts, sugars, proteins, and more cells red blood cells (RBC) transport O2 in hemoglobin white blood cells (WBC) defense & immunity platelets blood clotting

Hemoglobin Protein which carries O2 O2 O2 O2 O2

emergency repair of circulatory system Blood clotting chemical emergency signals platelets seal the hole protein fibers build the clot Inherited defect in any step of the clotting process causes hemophilia, characterized by excessive bleeding from even minor cuts & bruises

Vertebrate Heart 4-Chambered heart atria (atrium) ventricles thin wall collection chamber receive blood ventricles thick wall pump pump blood out left atrium right atrium right ventricle left ventricle

Lub-dub, lub-dub 4 valves in the heart Heart sounds Heart murmur flaps of tissue prevent backflow of blood Heart sounds closing of valves “Lub” force blood against closed AV valves “Dub” force of blood against semilunar valves Heart murmur leaking valve causes hissing sound SL AV AV

Arteries: Built for their job blood flows away from heart thicker walls elastic & stretchable

Veins: Built for their job Blood flows toward heart Veins blood returns back to heart thinner-walled Open valve Closed valve

Structure-function relationship Capillaries very thin walls allows diffusion of materials across capillary O2, CO2, H2O, food, waste body cell waste CO2 O2 food

Blood vessels arteries arterioles capillaries venules veins veins artery arterioles venules arterioles capillaries venules veins

Circulation of Blood 2 part system Circulation to lungs blood gets O2 from lungs drops off CO2 to lungs brings O2-rich blood from lungs to heart Circulation to body pumps O2-rich blood to body picks up nutrients from digestive system collects CO2 & cell wastes lungs heart body Circulation to body

Vertebrate circulatory system 2 part system lungs artery to lungs vein from lungs to heart heart vein from body to heart artery to body body St. Joseph's Aspirin Commercial

Electrical signals heart pumping controlled by electrical impulses stimulates ventricles to contract from bottom to top, driving blood into arteries allows atria to empty completely before ventricles contract heart pumping controlled by electrical impulses signal also transmitted to skin = EKG

atria empty into ventricles fill (minimum pressure) Cardiac Cycle How is this reflected in blood pressure measurements? chambers begin to fill pump (peak pressure) __________________ fill (minimum pressure) The cardiac cycle. For an adult human at rest with a pulse of about 75 beats per minute, one complete cardiac cycle takes about 0.8 second. During a relaxation phase (atria and ventricles in diastole), blood returning from the large veins flows into the atria and ventricles. A brief period of atrial systole then forces all remaining blood out of the atria into the ventricles. During the remainder of the cycle, ventricular systole pumps blood into the large arteries. Note that 7/8 of the time—all but 0.1 second of the cardiac cycle—the atria are relaxed and are filling with blood returning via the veins. 110 80 ______ ventricles pump

Measurement of blood pressure if top number > 150 or if bottom number > 90 hypertension = (high blood pressure)

Coronary artery bypass bypass surgery

Cardiovascular disease Atherosclerosis & Arteriosclerosis deposits inside arteries (plaques) develop in inner wall of the arteries, narrowing their channel increase blood pressure increase risk of heart attack, stroke, kidney damage normal artery hardening of arteries

Cardiovascular health bypass surgery Risk Factors genetics diet high animal fat exercise & lifestyle smoking lack of exercise

Have a heart? Ask Questions!! 2008-2009