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Tainted Love. Introduction. Function: Transport materials around body Components: Heart Blood Vessels. The Heart. Layers in Cross Section: Pericardium - outermost sac enclosing heart Pericardial Fluid- fluid between pericardium and epicardium
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Introduction • Function: • Transport materials around body • Components: • Heart • Blood Vessels
The Heart • Layers in Cross Section: • Pericardium- outermost sac enclosing heart • Pericardial Fluid- fluid between pericardium and epicardium • Epicardium- tight fitting layer surrounding heart; also called visceral pericardium • Myocardium- cardiac muscle layer • Endocardium- smooth inner layer of heart
Heart Structure • Four chambers: • Right and left atria- receive blood into heart • Right and left ventricle- pump blood back out of the heart • Two sides are separated by septum
Valves • Four Valves in Heart: • Tricuspid - between right atrium and right ventricle • Pulmonary Semilunar- between right ventricle and pulmonary trunk • Mitral (Bicuspid) - between left atrium and left ventricle • Aortic semilunar- between left ventricle and aorta
Two Circulations of Blood • Pulmonary: • Back and forth to lungs • Systemic: • Back and forth to body
Exit Slip • 1) What chamber is this? • 2) Which valve is between right atrium and right ventricle? • 3) Which circuit (pulmonary or systemic) brings blood back and forth to lungs? • 1) Right atrium • 2) Tricuspid • 3) Pulmonary
Vessels Supplying the Heart • Coronary arteries • First two branches off of the aorta • Supply blood to heart • Cardiac veins • Return blood from heart tissues • Drain into coronary sinus • Coronary sinus • Returns blood back to right atrium
Cardiac Cycle • Sequence of events that occur during every regular heartbeat • Systole - contraction • Diastole - relaxation • Refer to timeline Systole/Diastole Song
Heart Sounds • Lubb - sound of atrioventricular (AV) valves closing • Dupp - sound of semilunar valves closing
Lubb, Dubb, …. Lubb, Dubb…. • made by the closing of the heart valves. • "lub" made by the contraction of the ventricles and the closing of the atrioventricular valves. • “dupp" made by the semilunar valves closing.
Reminder about Cardiac Tissue • Complex network of interconnecting cells • Connected by intercalated discs • Allows them to transfer impulse rapidly and work together (functional syncytium) • Two sets in heart: • One in atria, one in ventricles • Kept separate from each other
Cardiac Conduction Intro • Electrical impulses cause heart structures to contract • Travel down a system of specialized fibers
QUICK REVIEW OF HEART Purpose • Pumps blood Basic Anatomy • 4 chambers • 2 sides • 4 valves
THE CONDUCTINGY SYSTEM • SA Node • Inter-nodal pathway • AV Node • Bundle of HIS • Bundle Branches • Purkinje Fibers
Why do we do an ECG? • Measures: • Any damage to the heart • How fast your heart is beating and whether it is beating normally • The effects of drugs or devices used to control the heart (such as a pacemaker) • The size and position of your heart chambers • Ordered if: • You have chest pain or palpitations (pounding/racing heart) • You are scheduled for surgery • You have had heart problems in the past • You have a strong history of heart disease in the family
Pathway for Conduction • Sinoatrial node (SA node) • Pacemaker • Causes atria to contract • Junctional Fibers • Delay impulse reaching ventricle by their small diameter • Atrioventricular node (AV node) • Purkinje fibers • Cause ventricles to contract
Electrocardiogram • Also know as ECG • Electrical recording of myocardium during cardiac cycle • P wave • Atrial depolarization • QRS complex • Ventricle depolarization and atrialrepolarization • T wave • Ventricle repolarization
Each electrical signal begins in a group of cells called the sinus node or sinoatrial (SA) node. The SA node is located in the right atrium (AY-tree-um), which is the upper right chamber of the heart. (Your heart has two upper chambers and two lower chambers.) • In a healthy adult heart at rest, the SA node sends an electrical signal to begin a new heartbeat 60 to 100 times a minute. • From the SA node, the signal travels through the right and left atria. This causes the atria to contract, which helps move blood into the heart's lower chambers, the ventricles (VEN-trih-kuls). The electrical signal moving through the atria is recorded as the P wave on the EKG. • The electrical signal passes between the atria and ventricles through a group of cells called the atrioventricular (AV) node. The signal slows down as it passes through the AV node. This slowing allows the ventricles enough time to finish filling with blood. On the EKG, this part of the process is the flat line between the end of the P wave and the beginning of the Q wave. • The electrical signal then leaves the AV node and travels along a pathway called the bundle of His. From there, the signal travels into the right and left bundle branches. The signal spreads quickly across your heart's ventricles, causing them to contract and pump blood to your lungs and the rest of your body. This process is recorded as the QRS waves on the EKG. • The ventricles then recover their normal electrical state (shown as the T wave on the EKG). The muscle stops contracting to allow the heart to refill with blood. This entire process continues over and over with each new heartbeat.
Control of Heart Rate • Cardiac Center of Medulla Oblongata • Parasympathetic • Constant braking action; acetylcholine • Sympathetic • Increases heart rate; norepinephrine • Blood Pressure Receptors • Decreases heart rate • Impulses from Cerebrum and Hypothalamus • Decrease heart rate • Changes in K and Ca concentrations
Thumbs Up, Down • Coronary arteries supply blood to heart. • UP! • The lubb of your heart is the sound of the AV closing/opening. • UP! • An ECG measures your blood pressure. • DOWN! It measures your cardiac cycle.
Blood Vessels • System of closed tubes filled with blood • Arteries • Carry blood away from heart • Arterioles • Smaller branches of arteries • Capillaries • Thin-walled vessels where nutrients, fluid, gases, and wastes are exchanged • Venules • Small veins • Veins • Large vessels returning blood to heart
Layers of Blood Vessel Walls • Tunica externa • Outermost layer composed of connective tissue with some elastic and collagenous fibers • Tunica media • Middle layer composed of smooth muscle and elastic fibers • Tunica interna (endothelium) • Single layer of squamous epithelium