Week 7 LO3 Cardiovascular System Part 2 PDF

LO3_Cardiovascular System Part 2. Week 7_Fall 202410 Monday, October 7, 2024  CLO-3-Cardiovascular System-2 2 Learning Outcomes CLO 3: Explain the structure, function and interdependence of the cardiovascular and res...

LO3_Cardiovascular System Part 2. Week 7_Fall 202410 Monday, October 7, 2024  CLO-3-Cardiovascular System-2 2 Learning Outcomes CLO 3: Explain the structure, function and interdependence of the cardiovascular and respiratory systems: 3.4 Discuss the coronary circulation. 3.5 Trace the course of blood through the chambers of the heart and describe the double circulation. 3.6 Explain the initiation and conduction of electrical impulses through the heart to show the coordination of the cardiac cycle and distinguish between systolic and diastolic pressure. 3.7 Relate the cardiac impulse to a normal ECG trace. 3.8 Explain the need for maintenance of a pressure gradient to facilitate blood flow.  3 Recap Activity Label the parts of the heart 1. 2. 3. 4. 5. 6. 7. 8. 9. 10 11. 12. 13. 14. 15. 16. 17.  Cardiovascular System CLO-3-Cardiovascular System-2 4 The cardiovascular system consists of the heart, blood vessels and the blood that flows through them. The heart acts as a pump, ensuring that blood circulates through every blood vessel in the body to: 1. Supplying cells with the oxygen and nutrients 2. Removing waste products and CO2. The heart acts as two strong muscular pumps, one for the pulmonary circuit and one for systemic circuit.  CLO-3-Cardiovascular System-2 6 Blood Circulations The pulmonary circuit sends oxygen poor blood (deoxygenated blood) to the lungs to pickup oxygen O2 and unload the carbon dioxide CO2. The pathway of blood in the pulmonary circuit is: Right ventricle – pulmonary arteries- lungs- pulmonary veins – left atrium The systemic circuit sends oxygen rich blood (oxygenated blood) and nutrients to all body cells and remove wastes and CO2. The pathway of blood in the systemic circuit is: Left ventricle – Aorta – body – vena cava – right atrium Pulmonary and Systemic Circulation  The Course of the Blood through the Chambers of the Heart Right side Left side Deoxygenated blood Oxygenated blood (venous)flows from flows through the the body through right and left superior and inferior pulmonary veins from vena cava and the right and left empties into the right lungs, into the left atrium. It passes atrium. It passes through the right through the left atrioventricular atrioventricular (Tricuspid) valve into (Bicuspid) valve into the right ventricle, the left ventricle, and from which it is from there it is pumped through the pumped out through pulmonary trunk the Aorta to the body. separating into the Both atria contract at right and left the same time, pulmonary arteries and into the right and Cardiac Cycle followed by simultaneous left lungs contraction of both ventricles. 8 Blood Supply to the Heart-Coronary Circulation CLO-3-Cardiovascular System-2 9 1. Coronary Arteries: The heart receives its own supply of blood (O2 and nutrients) from the coronary arteries. Two major coronary arteries branch off from the aorta. Their openings lie superior to the aortic valve. They are called the left coronary artery and the right coronary artery. 2. Coronary Veins: Coronary veins are blood vessels that collect carbon dioxide (CO2) and wastes from the heart muscle. The main coronary veins are great cardiac vein, middle cardiac vein and small cardiac vein They all drain the deoxygenated blood into a large vascular sinus on the posterior surface of the heart called the coronary sinus, which is a wide venous channel (enlarged vein) empties into the right atrium. Path of Blood through the Coronary Circulation Coronary sinus: it is a wide venous channel situated in the posterior part of coronary sulcus and ends in the right atrium  How Does the Blood Flow? CLO-3-Cardiovascular System-2 11 Blood flows through the cardiovascular system by moving from an area of high pressure to an area of low pressure. In the heart, the changes in pressure are brought about by contraction and relaxation of the atria and ventricles: Contraction systole BP Relaxation diastole High Low This refers to the events in one heartbeat (cardiac cycle) that takes 0.8 second. Blood flows from high to low pressure. Pressure generated during contraction. Heartbeat = contraction (systole) & relaxation (diastole).  CLO-3-Cardiovascular System-2 12 Important Terms Contraction produces an area of high pressure. Relaxation produces an area of low pressure. - Contraction of the heart chambers is called: systole. - Relaxation of the heart chambers is called: diastole. - Contraction of the atria called: atrial systole. - Relaxation of the atria is called: atrial diastole. - Contraction of the ventricles is called: ventricular Systole. - Relaxation of the ventricles is called: ventricular diastole The Cardiac Cycle Phases CLO-3-Cardiovascular System-2 13 First Phase: Atrial Systole/Ventricular Diastole Atria contract (systole) to pump final volume into ventricles Ventricles are relaxed (diastole) AV valves (Tricuspid, Mitral) are opened Semilunar valves are closed. Phases Champers Valves 1 Atria: contracted AV: opened Ventricles: relaxed SL: closed The Cardiac Cycle Phase CLO-3-Cardiovascular System-2 14 Second Phase: Ventricular Systole/Atrial Diastole Ventricles contract (systole) when filled with blood Closes (AV) Atrioventricular (tricuspid and mitral) valves (lub sound) Opens semilunar (Pulmonic and aortic) valves, blood passes to the arteries As ventricles start to relax, high pressure in arteries causes semilunar valves to close (Dub sound) Atria are relaxed (diastole) and starting to fill up with blood returning from veins Phases Champers Valves Atria: relaxed AV: closed 2 Ventricles: SL: opend-1 Contracted-1 Closed-2 Relaxed-2 (Lub & Dub) The Cardiac Cycle Phase CLO-3-Cardiovascular System-2 15 Third Phase: Diastole (very short period) All chambers relaxed Semilunar valves closed Pressure in atria causes (AV) Atrioventricular (tricuspid and mitral) valves to open Blood drains to the ventricles Phases Champers Valves 3 Atria: relaxed AV: opened Ventricles: relaxed SL: closed The Cardiac Cycle Phase CLO-4-Cardiovascular System-2 16 3 1 1 2 2  CLO-3-Cardiovascular System-2 17 Heart Sounds A heartbeat heard through a stethoscope sounds like (Lub-dub) Lub sound = Closing (AV) Atrioventricular (tricuspid and mitral) valves Dub sound = Closing (SL) semilunar vale (pulmonary and aorta) valves Murmur = faulty valves cusps, inadequate closing (do not close adequately). http://depts.washington.edu/physdx/heart/demo.html The Cardiac Cycle  The Conduction System of the Heart CLO-3-Cardiovascular System-2 19 A major portion of the heart (99%) is made up of cardiomyocytes (contractile fibers). About 1% of the heart cells are autorhythmic cells (myogenic cells). Myogenic means “originating in the muscle cells”. This means that action potential is originating in these cells. The Action potentials, are initiated by these autorhythmic cells in the sinoatrial node, then spread throughout the intrinsic conduction system and excite the contractile fibers (cardiomyocyte), causing atrial and ventricular contraction. This is done with the help of intercalated discs that are found between cardio myocytes and provide a site for cell-to-cell adhesion and permit the cell-to-cell flow of ions. Conducting System of Heart The Conduction System of the Heart CLO-3-Cardiovascular System-2 21 The heart regulates the rate and strength of contraction through this intrinsic conduction system. This system is the electrical conduction system that controls the heart rate. It consists of: 1. Sinoatrial node (SA node) 2. Atrioventricular node (AV node) 3. Bundle of His (AV Bundle) 4. Right & Left Bundle Branches 5. Purkinje Fibers  The Conduction System of the Heart CLO-3-Cardiovascular System-2 22 1. Sinoatrial Node (SA node) (Part I): Located in back wall of the right atrium near the entrance of superior vena cava Called the pacemaker of the heart Initiates impulses 70-80 times per minute without any nerve stimulation from brain Establishes basic rhythm of the heartbeat Impulses move through atria causing the two atria to contract. At the same time, impulses reach the second part of the conduction system  CLO-3-Cardiovascular System-2 23 The Conduction System of the Heart 2. Atrioventricular Node (AV node) (Part II): Located in the bottom of the right atrium near the septum Cells in the AV node conduct impulses more slowly, so there is a delay as impulses travel through the node This allows time for atria to finish contraction before ventricles begin contracting The Conduction System of the Heart CLO-3-Cardiovascular System-2 24 3. AV bundle (Bundle of His) (Part III) Enters the upper part of the interventricular septum and divides into right and left bundle branches. 4. Right and left bundle branches (Part IV) These branches extend to the right and left sides of the septum and bottom of the heart. 5. Purkinje Fibers (Part V) Conduct the impulses to the apex of the heart Contraction begins at the apex and push the blood toward the aortic and pulmonary valves  CLO-3-Cardiovascular System-2 25 The Electrocardiogram The electrocardiogram (ECG) is used as indicator of cardiac function, where it can amplify and record the electrical activity of the heart during a cardiac cycle. Electrical activity can be recorded by placing electrodes on the surface of the body on opposite sides of the heart. ECG patterns are used to indicate various cardiac disorders, including heart damage during or following heart attacks.  The Electrocardiogram CLO-3-Cardiovascular System-2 26 A normal ECG pattern includes several deflections or waves during each cardiac cycle. The P wave = Depolarization of the atrial cells/ the spread of the electrical impulse over the atria just before atrial contraction. The QRS complex = Depolarization of the ventricles/ the spread of the electrical impulses through the ventricles just before ventricular contraction. The T wave = Ventricular repolarization / electrical currents generated as the ventricles recover after contraction Pinoquio Reads Story Text http://tbn3.google.com/images?q=tbn:O8VTycAcvoMXkM:http://www.vanth.org/vibes/images/normalECG2.PNG References Welsh. (2022) Hole’s Human Anatomy & Physiology. 16th Edition. New York: McGraw-Hill Education. ISBN 1264262833. Shier, D., Butler, J. and Lewis, R. (2018) Hole’s Essentials of Human Anatomy & Physiology. 14th Edition. New York: McGraw-Hill Education. ISBN 9781259869433 Moini, J. (2015). Anatomy and physiology for health professionals. Jones & Bartlett Publishers. 27  Thank You 800 MyHCT (800 69428) www.hct.ac.ae