HEART ANATOMY & FUNCTION OF THE CARDIOVASCULAR SYSTEM Unit 11.1 in Text

Vocabulary Need to Know  Aorta  Aortic Valve  Atrioventricular (AV valves)  Cardiac Output  Diastole  Endocardium  Epicardium  Inferior Vena Cava  Tricuspid Valve  Vasoconstriction  Interatrial Septum  Interventricular Septu  Mitral Valve  Myocardium  Papillary muscle  Semilunar Valves  Stroke Volume  Superior Vena Cava  Systole  Vasodilation

Lesson Objectives  Describe the function of the cardiovascular system.  Describe the location, size, and structures of the heart.  Outline the flow of blood through the cardiopulmonary system.  Describe how the blood flows from the arteries to the veins.

Introduction  Cardiovascular system AKA Circulatory System  Transports oxygen, hormones, other nutrients to cells  Rids the body of carbon dioxide and other metabolic waste  Regulates body temperature  Assists with immune function  Has 3 parts  Heart (pump)  Blood Vessels (network of pipes)  Blood (fluid)

Vasoconstriction and Vasodilation  Vasodilation  Increase in the diameter of the blood vessels (expansion) Increases blood flow  Vasoconstriction  Decrease in the diameter of the blood vessels Decreases blood flow

Vasoconstriction and Vasodilation

Heart: Location and Size  Normally beats bpm  Approx. 3 Billion beats per lifetime  Fatigue resistant  About the size of a clenched fist  Located in the thoracic cavity, more specifically in the mediastinum, under the breastbone  Centered in the chest and tilted slightly to the left  Lungs are on either side  Sits on top of the diaphragm  Base of heart is closer to the neck  Apex (bottom) of heart is at 5 th rib and points toward left hip

Heart: Location and Size

Heart Chambers  Four Chambers  Right Atrium  Right Ventricle  Left Atrium  Left Ventricle  Interatrial Septum  Seperates the right and left atria  Interventricular Septum  Divides right and left ventricles  Much thicker than interatrial septum  Septal walls prevent oxygen rich blood from mixing with oxygen poor blood

Blood Flow Through Chambers  Inferior Vena Cava & Superior Vena Cava deliver deoxygenated blood to right atrium  Right atria Right Ventricle  Right Ventricle Lungs  Lungs Left Atrium  Left Atrium Body, through the Aorta  Simultaneous Ventricular Contraction  How could this explain the size and layout of the heart?

Heart Anatomy

Heart Valves  Four Valves  Atrioventricular (AV)  Located between the atria and the ventricles  When open, allow blood flow from atria to ventricles  When closed, prevent back flow  Tricuspid Valve Three Cusps/Flaps Between Right Atrium and Ventricle  Bicuspid/Mitral Valve Two Flaps Between Left Atrium and Ventricle

Heart Valves  Flaps are connected to papillary muscles by the chordae tendineae  Prevents the flaps from swinging into the atria  If flaps swung the opposite way (think dog door) then the backward flow would result in a heart murmur

Heart Valves  Semilunar Valves  Let blood flow from ventricles to lungs/body  Do not need to be anchored, cusps/flaps brace each other  Pulmonary Valve Located at the opening of the pulmonary artery on the Right side of the heart  Aortic Valve Located at the opening of the aorta on the Left side of the heart

Blood Flow Through the Heart Deoxygenated blood enters the right atrium from the inferior and superior vena cava. Collecting blood increases the blood pressure against Tricuspid valve, forcing it open Right ventricle fills passively because of pressure, then atrium contracts, forcing remaining blood into the ventricle Right ventricle contracts, and pressure increases, forcing the tricuspid valve to close and the pulmonary valve to open, blood flows into pulmonary artery Pulmonary artery carries blood to lungs where it is oxygenated Oxygenated blood returns to left atrium via pulmonary veins Blood collects in left atrium, pressure increases, forcing the mitral (AV) valve to open Left Ventricle fills passively until atrial contraction forces remaining blood in Left Ventricle contracts, pressure increases, closing mitral valve and opening aortic valve

Blood Flow Animation 