Cardiovascular System Chapter 42 IB Biology

Biological Function of Cardiovascular System T R A N S P O R T ! –Maintains constant flow of : Nutrients Hormones Respiratory Gases Wastes Enzymes to /from tissue cells!

3 Major Components of CV System 1.Blood 2.Blood Vessels 1.Arteries / Arterioles 2.Veins / Venules 3.Capillaries 3.Heart

Heart Anatomy grams--size of fist Located in mediastinum Rests on diaphragm 2/3 left of midline Shifts toward right shoulder Apex points to left hip

Protective Features of the Heart P E R I C A R D I U M Layered membrane surrounding heart Fibrous pericardium –Tough, superficial layer Serous pericardium –Thin, deep layer subdivided into: Parietal layer: lines underside of fibrous pericardium Epicardium: lines external surface of heart Pericardial cavity: btwn parietal layer and epicardium filled with fluid!

Pericarditis Inflammation of pericardium Pericardial fluid increases pressure on heart Cardiac tamponade

Heart Anatomy 3 Layers of Heart Wall 1.Epicardium: Superficial Layer Composed of CT 2. Myocardium: Intermediate Layer Composed of Muscle 3. Endocardium: Deep Layer Composed of Endothelium

Internal Heart Anatomy FOUR CHAMBERS 2 ATRIA (Right Atrium, Left Atrium) Entry Chambers 2 VENTRICLES (Right Ventricle, Left Ventricle) Exit Chambers

Right atrium Left atrium Right ventricle Left ventricle

So what’s the big deal about a four chambered heart? E F F I C I E N C Y

What leads to the heart’s efficiency? A T R I O V E N T R I C U L A R S E P T U M wall that creates a physical separation between right and left sides of heart (Interatrial septum + Interventricular septum = Atrioventricular Septum)

A V SEPTUM

How does the AV septum lead to efficiency? Creates two hearts in one! Maintains separation between oxygenated blood (high O 2 / low CO 2 ) and deoxygenated blood (low O 2 / high CO 2 ) Oxygenated blood always on left side! Deoxygenated blood always on right side!

Mixing of Blood Occurs! Mixing of Blood Prevented!

FOUR MAJOR BLOOD VESSELS ATTACHED TO HEART 1.VENA CAVA major vein of body 2.AORTA major artery of body 3. PULMONARY ARTERY 4. PULMONARY VEIN

superior vena cava inferior vena cava pulmonary artery aorta pulmonary veins pulmonary veins

Coronary Artery Provides blood to the myocardium of the heart!

Arteries vs. Veins ARTERY Always conducts blood AWAY from the heart! Usually carries oxygenated blood VEIN Always conducts blood TOWARD the heart! Usually carries deoxygenated blood

Heart Valves Flaps that open/close passageways for blood through the heart

2 Major Types of Valves: 1.Atrioventricular (AV) Valves Found between atria and ventricles Right AV Valve = Tricuspid Valve Left AV Valve = Bicuspid Valve / Mitral Valve

Chordae tendinae / papillary muscles Open/close AV valves Prevent valves from opening backwards

Valves prevent backflow incompetent valve heart murmur

2.Semilunar Valves found between ventricles and blood vessels leading out of the heart Right Valve = Pulmonary Semilunar Valve Left Valve = Aortic Semilunar Valve

31 Right AV (tricuspid) Left AV (bicuspid) Pulmonary semilunar Aortic semilunar

Circulatory Pathways Systemic Circulation: blood flows to/from body tissues Pulmonary Circulation: blood flows to/from lungs Coronary Circulation: blood flows to/from heart muscle

The Heart’s Assignment… …maintaining blood flow through ALL circulatory pathways of the body!

Right side receives blood from tissues and pumps to lungs (pulmonary circulation) Left side receives blood from lungs and pumps to tissues (systemic circulation)

Pathway of Blood Through the Heart Heart acts as double pump (Rt side/left side) Both pumps act in unison Deoxygenated blood returns to heart through vena cava Right side pumps blood to lungs Oxygenated blood returns to heart through pulmonary veins Left side pumps blood to body

Blood through the heart

Capillaries of lungs for oxygenation Inferior & superior vena cavae Right atrium Tricuspid valve Right ventricle Pulmonary semi- lunar valve Pulmonary trunk (arteries)

Arteries of body Capillaries of tissues--exchange gases Veins of body Pulmonary veins Left atrium Bicuspid valve Left ventricle Aortic semi- lunar valve Aorta