The Cardiovascular System Slide 11.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  A closed system of the heart and blood vessels  The heart pumps blood  Blood vessels allow blood to circulate to all parts of the body  Function: to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

The Heart Slide 11.2a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Location  Thorax between the lungs  Pointed apex directed toward left hip  Base points toward right shoulder  About the size of your fist

The Heart Slide 11.2b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.1

The Heart: Coverings Slide 11.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Pericardium – a double serous membrane  Visceral pericardium  Next to heart  Parietal pericardium  Outside layer  Serous fluid fills the space between the layers of pericardium

The Heart: Heart Wall Slide 11.4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Three layers  Epicardium  Outside layer  This layer is the parietal pericardium  Connective tissue layer  Myocardium  Middle layer  Mostly cardiac muscle  Endocardium  Inner layer  Endothelium

External Heart Anatomy Slide 11.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.2a

The Heart: Chambers Slide 11.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Right and left side act as separate pumps  Four chambers  Atria  Receiving chambers  Right atrium  Left atrium  Ventricles  Discharging chambers  Right ventricle  Left ventricle

Slide 11.6 Internal Heart Anatomy Internal Heart Anatomy Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Blood Circulation Slide 11.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.3

Pulmonary Circuit Slide 11.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Function—carry blood to lungs for gas exchange and return it to the heart  Blood vessels involved  Pulmonary arteries—carry oxygen-poor blood to the lungs away from the heart  Pulmonary veins—carry oxygen-rich blood to the heart from the lungs

Systemic Circuit Slide 11.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Function—carries oxygen- and nutrient- rich blood to all body organs, and carries oxygen-poor blood back to heart  Blood vessels involved  Arteries—carries oxygen-rich blood from heart to body  Veins—carries oxygen-poor blood from body to heart

The Heart: Valves Slide 11.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Allow blood to flow in only one direction  Four valves  Atrioventricular valves – between atria and ventricles  Bicuspid valve (left)  Tricuspid valve (right)  Semilunar valves between ventricle and artery  Pulmonary semilunar valve  Aortic semilunar valve

The Heart: Valves Slide 11.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Valves open as blood is pumped through  Held in place by chordae tendineae (“heart strings”)  Close to prevent backflow

Operation of Heart Valves Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.4

The Heart: Associated Great Vessels Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Aorta  Leaves left ventricle  Pulmonary arteries  Leave right ventricle  Vena cava  Enters right atrium  Pulmonary veins (four)  Enter left atrium

Coronary Circulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Blood in the heart chambers does not nourish the myocardium  The heart has its own nourishing circulatory system  Coronary arteries  Cardiac veins  Blood empties into the right atrium via the coronary sinus

Circulatory homeostatic imbalances Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Angina pectoris  Myocardium is deprived of oxygen when there is not enough blood supply, resulting in crushing chest pain  Myocardial infarction  “heart attack” or “coronary”  Ischemic (decrease in blood supply) heart cells die forming an infarct (region of dead tissue)

The Heart: Conduction System Slide 11.13a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Intrinsic conduction system (nodal system)  Heart muscle cells contract, without nerve impulses, in a regular, continuous way  Enforces contraction rate of ~75 beats/min

The Heart: Conduction System Slide 11.13b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Special tissue sets the pace 1.Sinoatrial node—pacemaker (highest rate of depolarization, starts each heartbeat) 2.Atrioventricular node 3.Atrioventricular bundle (Bundle of His) 4.Bundle branches (right and left) 5.Purkinje fibers

Heart Contractions Slide 11.14b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.5

The Heart: Cardiac Cycle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cardiac cycle – events of one complete heart beat (~0.8 sec)  Atrial systole and diastole followed by ventricular systole and diastole  Atria contract simultaneously  Atria relax, then ventricles contract  Most pumping is done by ventricles  Systole = contraction  Diastole = relaxation

The Heart: Cardiac Cycle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Mid-to-late diastole (relaxation) – blood flows into ventricles  Ventricular systole – blood pressure builds before ventricle contracts, pushing out blood (atria are relaxed and filling with blood)  Early diastole – atria finish re-filling, ventricular pressure is low, semilunar valves shut

Slide The Heart: Cardiac Cycle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Mid-to-late DiastoleVentricular SystoleEarly Diastole 1.PRESSURE LOW 2.AV VALVES OPEN 3.SEMILUNAR VALVES CLOSED 4.BLOOD FLOWS INTO VENTRICLES 5.ATRIA CONTRACT, VENTRICLES RELAX 1.PRESSURE HIGH 2.AV VALVES CLOSE 3.SEMILUNAR VALVES FORCED OPEN 4.BLOOD PUSHED OUT OF VENTRICLES INTO PULMONARY TRUNK/AORTA 5.ATRIA RELAX, VENTRICLES CONTRACT 1.PRESSURE LOW 2.AV VALVES OPEN 3.SEMILUNAR VALVES SNAP SHUT 4.VENTRICLES REFILL WITH BLOOD 5.ATRIA BEGIN TO CONTRACT, VENTRICLES RELAX

Filling of Heart Chambers – the Cardiac Cycle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.6

Heart Sounds Slide 11.14a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Lub-dup, pause, lub-dup, pause…  Lub-first sound louder and longer when AV valves close  Signifies start of systole when ventricular pressure rises above atrial pressure  -dup-sharp sound when SL valves snap shut  Signifies start of ventricular diastole

The Heart: Cardiac Output Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cardiac output (CO)  Amount of blood pumped by each side of the heart in one minute  CO = (heart rate [HR]) x (stroke volume [SV])  Stroke volume  Volume of blood pumped by each ventricle in one contraction

Cardiac Output Regulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.7