logging in or signing up heart aSGuest12613 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 3616 Category: Entertainment License: All Rights Reserved Like it (2) Dislike it (0) Added: February 08, 2009 This Presentation is Public Favorites: 2 Presentation Description No description available. Comments Posting comment... By: vyavahare (17 month(s) ago) Excellent Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript CIRCULATORY SYSTEM : CIRCULATORY SYSTEM The Heart BASIC HEART STRUCTURE : BASIC HEART STRUCTURE Arteries Carry blood from the heart to tissues Artery ? Arterioles ? Capillaries Capillaries Site of gas and nutrient exchange Veins Return blood to the heart from tissues Capillaries ? Venules ? Veins FUNCTIONS OF THE HEART : FUNCTIONS OF THE HEART Two major division Pulmonary circuit Carries blood from heart to lungs & back Gas exchange: lose CO2, gain O2 Right side of heart Systemic circuit Carries blood from heart to body organs & back Gas exchange: lose O2, gain CO2 Left side of heart HEART STRUCTURE : HEART STRUCTURE CHAMBERS Atria Right and left Superior Separated by interatrial septum Ventricles Right and left Inferior Separated by interventricular septum BLOOD FLOW THROUGH THE HEART : BLOOD FLOW THROUGH THE HEART Right atrium Receives O2-poor blood from body tissues Right ventricle Receives O2-poor blood from right atrium Pumps O2-poor blood to lungs Left atrium Receives O2-rich blood from lungs Left ventricle Receives O2-rich blood from left atrium Pumps O2-rich blood to body organs HEART VALVES : HEART VALVES Consist of fibrous flaps Ensure unidirectional flow Open and close in response to pressure differences between sides Atrioventricular (AV) valves Semilunar valves HEART VALVES : HEART VALVES ATRIOVENTRICULAR (AV) VALVES Right AV valve Also known as tricuspid valve Left AV valve A.K.A. bicuspid valve A.K.A. mitral valve HEART VALVES : HEART VALVES ATRIOVENTRICULAR (AV) VALVES Atrium ? Ventricle Ventricle relaxed Valve open Atrium ? Ventricle blood flow Ventricle contracts Ventricle pressure increases Valve closes Prevents back flow HEART VALVES : HEART VALVES ATRIOVENTRICULAR (AV) VALVES Papillary muscles Contract with rest of ventricle Pull on chordae tendineae Chordae tendineae Connect AV valve cusps to papillary muscles to Reinforce AV valves Prevent prolapse HEART VALVES : HEART VALVES SEMILUNAR VALVES Ventricle ? Artery Ventricle relaxed Pressure higher in arteries Valve closed Ventricle contracts Pressure higher in ventricle Valves forced open Blood flows from heart HEART STRUCTURE : HEART STRUCTURE PERICARDIUM Double-walled sac Encloses heart Contains pericardial fluid (5-30 ml) Greatly reduces friction HEART STRUCTURE : HEART STRUCTURE HEART WALL Epicardium (outer) Also known as visceral pericardium Myocardium Thickest layer Cardiac muscle Endocardium Smooth inner lining Continuous with blood vessels HEART STRUCTURE : HEART STRUCTURE MYOCARDIUM Thickest; Cardiac muscle Muscle fibers connected by fibrous (protein) skeleton Structural support Something to pull against Electrical nonconductor Allows atria and ventricles to contract separately CARDIAC MUSCLE STRUCTURE : CARDIAC MUSCLE STRUCTURE CARDIAC MUSCLE CELLS “Myocytes” / “Cardiocytes” Striated Short, thick (50 – 100 mm x 10 - 20 mm) Branched Single nucleus Less developed SR (SER) Larger T-Tubules (admit Ca++) Joined via intercalated disks CARDIAC MUSCLE STRUCTURE : CARDIAC MUSCLE STRUCTURE INTERCALATED DISK FEATURES Interdigitating folds Increased surface area contact Mechanical junctions Fascia adherens (actin) Desmosomes Electrical junctions Gap junctions Electrically stimulate neighbors CARDIAC METABOLISM : CARDIAC METABOLISM Exclusively aerobic Myoglobin-rich (stored O2) Glycogen-rich (stored sugar) Large mitochondria (25% VS 2%) Multiple fuels usable Vulnerable to O2 deficiency Not prone to fatigue (Aerobic ? No O2 debt ? No fatigue) CARDIAC RHYTHM : CARDIAC RHYTHM CARDIAC MYOCYTES Autorhythmic Spontaneous depolarization at regular intervals Some specialized to generate action potentials “Cardiac conduction system” Sinoatrial (SA) node Atrioventricular (AV) node CARDIAC RHYTHYM : CARDIAC RHYTHYM SINOATRIAL (SA) NODE Myocytes in right atrium “Pacemaker” Initiates heartbeat Determines heart rate Firing rate reduced by nerves 70 – 80 beats per minutes (BPM) CARDIAC RHYTHYM : CARDIAC RHYTHYM SINOATRIAL (SA) NODE Cells lack stable resting membrane potential Spontaneously depolarize and repolarize at regular intervals (~0.8 sec) Each depolarization initiates one heartbeat Generate action potential CARDIAC RHYTHYM : CARDIAC RHYTHYM SA ACTION POTENTIAL Spreads throughout atrial myocardium Atria contract ~ simultaneously Signal reaches AV node (50 msec) Delayed at AV node (100 msec) Ventricles fill during delay CARDIAC RHYTHYM : CARDIAC RHYTHYM ATRIOVENTRICULAR (AV) NODE Near right AV valve Electrical gateway to ventricles Distributes signal to ventricular myocardium AV bundle Purkinje fibers CARDIAC RHYTHYM : CARDIAC RHYTHYM Signal travels from AV through ventricular myocardium Ventricles contract ~simultaneously Papillary muscles contract first CARDIAC RHYTHYM : CARDIAC RHYTHYM CARDIAC ACTION POTENTIALS Prolonged depolarization 200 - 250 msec vs. 2 msec Result of slow Ca++ channels Sustained contraction Longer refractory period 200 msec vs. 1 – 2 msec Prevents wave summation, tetanus SYSTOLE / DIASTOLE : SYSTOLE / DIASTOLE Systole Contraction of a heart chamber Refers to ventricle unless otherwise noted Diastole Period during which a heart chamber relaxes and fills with blood ELECTROCARDIOGRAM : ELECTROCARDIOGRAM Electrical currents generated in the heart travel weakly through all body tissues These currents can be measured using electrodes applied to the skin Slide 34: P WAVE Signal from SA node depolarizes atria Atrial systole ~100 msec after P wave begins Slide 35: QRS COMPLEX Firing of the AV node Onset of ventricular depolarization Atrial repolarization / Diastole obscured Ventricular systole immediately after Slide 36: S – T SEGMENT Myocardial action potential plateau Ventricles are contracting Blood ejected from ventricles Slide 37: T WAVE Ventricular repolarization before diastole (Repolarization takes longer than depolarization) HEART SOUNDS : HEART SOUNDS First and second heart sounds S1 and S2 “Lubb-Dupp” Occur in conjunction with heart valves closing Bloodstream turbulence Third heart sound (S3) Sometimes heard in children and adolescents CARDIAC CYCLE : CARDIAC CYCLE Atrial systole Atrial diastole Ventricular systole Ventricular diastole Quiescent period CARDIAC CYCLE : CARDIAC CYCLE QUIESCENT PERIOD No contraction of any heart chambers Atria are filling CARDIAC CYCLE : CARDIAC CYCLE ATRIAL SYSTOLE SA node fires Atria depolarize P wave of ECG produced Atria contract Blood pressure in atria increases Blood forced into ventricles CARDIAC CYCLE : CARDIAC CYCLE ISOVOLUMETRIC CONTRACTION Atria repolarize, relax Atria in diastole for remainder Ventricles depolarize, contract Ventricular pressure increases AV valves close Heart sound S1 No blood ejected yet CARDIAC CYCLE : CARDIAC CYCLE VENTRICULAR EJECTION Ventricular pressure exceeds pressure in arteries Semilunar valves open Blood ejected into arteries Not all blood expelled Amount ejected = Stroke volume % = Ejection fraction CARDIAC CYCLE : CARDIAC CYCLE ISOVOLUMETRIC RELAXATION Early in ventricular diastole Blood briefly flows backwards Semilunar valves close Heart sound S2 AV valves not yet open No blood taken in yet CARDIAC OUTPUT : CARDIAC OUTPUT Heart rate (HR) (beats/min) ~75 BPM at rest Stroke volume (SV) ~70 ml/beat at rest Cardiac output (CO) CO = HR * SV 75 * 70 = 5,000 ml/min at rest Cardiac output is not constant CARDIAC OUTPUT : CARDIAC OUTPUT Cardiac output is not constant Resting ~5 liters/min resting (total volume) Vigorous exercise ~21 liters/min in good condition ~35 liters/min olympic athlete CO = HR * SV, CO increased by HR or SV increased CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Easily measured (pulse) 70 – 80 average resting rate Tachycardia: resting >100 BPM Brachycardia: resting <60 BPM Regulated by nervous system CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Regulated by cardiac center of medulla oblongata Cardioaccelatory center Cardioinhibitory center CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Cardioaccelatory center Thoracic spinal cord Cardiac accelerator nerves Secrete norepinephrine Binds to receptors in heart Increases heart rate CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Cardioinhibitory center Vagus nerves Secrete acetylcholine Send signals to AV and SA nodes Fire less frequently Intrinsic heart rate is 100 BPM CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Cardiac center receives input from multiple sources Proprioreceptors Physical activity Baroreceptors Blood pressure Chemoreceptors pH, [O2], [CO2] CARDIAC OUTPUT : CARDIAC OUTPUT STROKE VOLUME Governed by three factors Preload Contractility Afterload CARDIAC OUTPUT : CARDIAC OUTPUT PRELOAD Ventricular myocardium tension prior to contraction Skeletal muscles massage veins and increase venous return More tension when myocardium contracts More forceful contraction More blood expelled CARDIAC OUTPUT : CARDIAC OUTPUT CONTRACTILITY Contraction force for a given preload Myocytes more responsive to stimulation Affected by Ca++ concentrations Increased by Epinephrine, Norepinephrine Glucagon, cAMP Digitalis CARDIAC OUTPUT : CARDIAC OUTPUT AFTERLOAD Blood pressure in arteries just outside of semilunar valves Increased afterload reduces stroke volume Resistance Caused by anything impeding arterial circulation CARDIAC OUTPUT : CARDIAC OUTPUT EFFECTS OF EXERCISE Increased cardiac output Ventricular hypertrophy Increased stroke volume Proprioreceptors More efficient signals from muscles / joints Increased venous return Increased preload You do not have the permission to view this presentation. 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heart aSGuest12613 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 3616 Category: Entertainment License: All Rights Reserved Like it (2) Dislike it (0) Added: February 08, 2009 This Presentation is Public Favorites: 2 Presentation Description No description available. Comments Posting comment... By: vyavahare (17 month(s) ago) Excellent Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript CIRCULATORY SYSTEM : CIRCULATORY SYSTEM The Heart BASIC HEART STRUCTURE : BASIC HEART STRUCTURE Arteries Carry blood from the heart to tissues Artery ? Arterioles ? Capillaries Capillaries Site of gas and nutrient exchange Veins Return blood to the heart from tissues Capillaries ? Venules ? Veins FUNCTIONS OF THE HEART : FUNCTIONS OF THE HEART Two major division Pulmonary circuit Carries blood from heart to lungs & back Gas exchange: lose CO2, gain O2 Right side of heart Systemic circuit Carries blood from heart to body organs & back Gas exchange: lose O2, gain CO2 Left side of heart HEART STRUCTURE : HEART STRUCTURE CHAMBERS Atria Right and left Superior Separated by interatrial septum Ventricles Right and left Inferior Separated by interventricular septum BLOOD FLOW THROUGH THE HEART : BLOOD FLOW THROUGH THE HEART Right atrium Receives O2-poor blood from body tissues Right ventricle Receives O2-poor blood from right atrium Pumps O2-poor blood to lungs Left atrium Receives O2-rich blood from lungs Left ventricle Receives O2-rich blood from left atrium Pumps O2-rich blood to body organs HEART VALVES : HEART VALVES Consist of fibrous flaps Ensure unidirectional flow Open and close in response to pressure differences between sides Atrioventricular (AV) valves Semilunar valves HEART VALVES : HEART VALVES ATRIOVENTRICULAR (AV) VALVES Right AV valve Also known as tricuspid valve Left AV valve A.K.A. bicuspid valve A.K.A. mitral valve HEART VALVES : HEART VALVES ATRIOVENTRICULAR (AV) VALVES Atrium ? Ventricle Ventricle relaxed Valve open Atrium ? Ventricle blood flow Ventricle contracts Ventricle pressure increases Valve closes Prevents back flow HEART VALVES : HEART VALVES ATRIOVENTRICULAR (AV) VALVES Papillary muscles Contract with rest of ventricle Pull on chordae tendineae Chordae tendineae Connect AV valve cusps to papillary muscles to Reinforce AV valves Prevent prolapse HEART VALVES : HEART VALVES SEMILUNAR VALVES Ventricle ? Artery Ventricle relaxed Pressure higher in arteries Valve closed Ventricle contracts Pressure higher in ventricle Valves forced open Blood flows from heart HEART STRUCTURE : HEART STRUCTURE PERICARDIUM Double-walled sac Encloses heart Contains pericardial fluid (5-30 ml) Greatly reduces friction HEART STRUCTURE : HEART STRUCTURE HEART WALL Epicardium (outer) Also known as visceral pericardium Myocardium Thickest layer Cardiac muscle Endocardium Smooth inner lining Continuous with blood vessels HEART STRUCTURE : HEART STRUCTURE MYOCARDIUM Thickest; Cardiac muscle Muscle fibers connected by fibrous (protein) skeleton Structural support Something to pull against Electrical nonconductor Allows atria and ventricles to contract separately CARDIAC MUSCLE STRUCTURE : CARDIAC MUSCLE STRUCTURE CARDIAC MUSCLE CELLS “Myocytes” / “Cardiocytes” Striated Short, thick (50 – 100 mm x 10 - 20 mm) Branched Single nucleus Less developed SR (SER) Larger T-Tubules (admit Ca++) Joined via intercalated disks CARDIAC MUSCLE STRUCTURE : CARDIAC MUSCLE STRUCTURE INTERCALATED DISK FEATURES Interdigitating folds Increased surface area contact Mechanical junctions Fascia adherens (actin) Desmosomes Electrical junctions Gap junctions Electrically stimulate neighbors CARDIAC METABOLISM : CARDIAC METABOLISM Exclusively aerobic Myoglobin-rich (stored O2) Glycogen-rich (stored sugar) Large mitochondria (25% VS 2%) Multiple fuels usable Vulnerable to O2 deficiency Not prone to fatigue (Aerobic ? No O2 debt ? No fatigue) CARDIAC RHYTHM : CARDIAC RHYTHM CARDIAC MYOCYTES Autorhythmic Spontaneous depolarization at regular intervals Some specialized to generate action potentials “Cardiac conduction system” Sinoatrial (SA) node Atrioventricular (AV) node CARDIAC RHYTHYM : CARDIAC RHYTHYM SINOATRIAL (SA) NODE Myocytes in right atrium “Pacemaker” Initiates heartbeat Determines heart rate Firing rate reduced by nerves 70 – 80 beats per minutes (BPM) CARDIAC RHYTHYM : CARDIAC RHYTHYM SINOATRIAL (SA) NODE Cells lack stable resting membrane potential Spontaneously depolarize and repolarize at regular intervals (~0.8 sec) Each depolarization initiates one heartbeat Generate action potential CARDIAC RHYTHYM : CARDIAC RHYTHYM SA ACTION POTENTIAL Spreads throughout atrial myocardium Atria contract ~ simultaneously Signal reaches AV node (50 msec) Delayed at AV node (100 msec) Ventricles fill during delay CARDIAC RHYTHYM : CARDIAC RHYTHYM ATRIOVENTRICULAR (AV) NODE Near right AV valve Electrical gateway to ventricles Distributes signal to ventricular myocardium AV bundle Purkinje fibers CARDIAC RHYTHYM : CARDIAC RHYTHYM Signal travels from AV through ventricular myocardium Ventricles contract ~simultaneously Papillary muscles contract first CARDIAC RHYTHYM : CARDIAC RHYTHYM CARDIAC ACTION POTENTIALS Prolonged depolarization 200 - 250 msec vs. 2 msec Result of slow Ca++ channels Sustained contraction Longer refractory period 200 msec vs. 1 – 2 msec Prevents wave summation, tetanus SYSTOLE / DIASTOLE : SYSTOLE / DIASTOLE Systole Contraction of a heart chamber Refers to ventricle unless otherwise noted Diastole Period during which a heart chamber relaxes and fills with blood ELECTROCARDIOGRAM : ELECTROCARDIOGRAM Electrical currents generated in the heart travel weakly through all body tissues These currents can be measured using electrodes applied to the skin Slide 34: P WAVE Signal from SA node depolarizes atria Atrial systole ~100 msec after P wave begins Slide 35: QRS COMPLEX Firing of the AV node Onset of ventricular depolarization Atrial repolarization / Diastole obscured Ventricular systole immediately after Slide 36: S – T SEGMENT Myocardial action potential plateau Ventricles are contracting Blood ejected from ventricles Slide 37: T WAVE Ventricular repolarization before diastole (Repolarization takes longer than depolarization) HEART SOUNDS : HEART SOUNDS First and second heart sounds S1 and S2 “Lubb-Dupp” Occur in conjunction with heart valves closing Bloodstream turbulence Third heart sound (S3) Sometimes heard in children and adolescents CARDIAC CYCLE : CARDIAC CYCLE Atrial systole Atrial diastole Ventricular systole Ventricular diastole Quiescent period CARDIAC CYCLE : CARDIAC CYCLE QUIESCENT PERIOD No contraction of any heart chambers Atria are filling CARDIAC CYCLE : CARDIAC CYCLE ATRIAL SYSTOLE SA node fires Atria depolarize P wave of ECG produced Atria contract Blood pressure in atria increases Blood forced into ventricles CARDIAC CYCLE : CARDIAC CYCLE ISOVOLUMETRIC CONTRACTION Atria repolarize, relax Atria in diastole for remainder Ventricles depolarize, contract Ventricular pressure increases AV valves close Heart sound S1 No blood ejected yet CARDIAC CYCLE : CARDIAC CYCLE VENTRICULAR EJECTION Ventricular pressure exceeds pressure in arteries Semilunar valves open Blood ejected into arteries Not all blood expelled Amount ejected = Stroke volume % = Ejection fraction CARDIAC CYCLE : CARDIAC CYCLE ISOVOLUMETRIC RELAXATION Early in ventricular diastole Blood briefly flows backwards Semilunar valves close Heart sound S2 AV valves not yet open No blood taken in yet CARDIAC OUTPUT : CARDIAC OUTPUT Heart rate (HR) (beats/min) ~75 BPM at rest Stroke volume (SV) ~70 ml/beat at rest Cardiac output (CO) CO = HR * SV 75 * 70 = 5,000 ml/min at rest Cardiac output is not constant CARDIAC OUTPUT : CARDIAC OUTPUT Cardiac output is not constant Resting ~5 liters/min resting (total volume) Vigorous exercise ~21 liters/min in good condition ~35 liters/min olympic athlete CO = HR * SV, CO increased by HR or SV increased CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Easily measured (pulse) 70 – 80 average resting rate Tachycardia: resting >100 BPM Brachycardia: resting <60 BPM Regulated by nervous system CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Regulated by cardiac center of medulla oblongata Cardioaccelatory center Cardioinhibitory center CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Cardioaccelatory center Thoracic spinal cord Cardiac accelerator nerves Secrete norepinephrine Binds to receptors in heart Increases heart rate CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Cardioinhibitory center Vagus nerves Secrete acetylcholine Send signals to AV and SA nodes Fire less frequently Intrinsic heart rate is 100 BPM CARDIAC OUTPUT : CARDIAC OUTPUT HEART RATE Cardiac center receives input from multiple sources Proprioreceptors Physical activity Baroreceptors Blood pressure Chemoreceptors pH, [O2], [CO2] CARDIAC OUTPUT : CARDIAC OUTPUT STROKE VOLUME Governed by three factors Preload Contractility Afterload CARDIAC OUTPUT : CARDIAC OUTPUT PRELOAD Ventricular myocardium tension prior to contraction Skeletal muscles massage veins and increase venous return More tension when myocardium contracts More forceful contraction More blood expelled CARDIAC OUTPUT : CARDIAC OUTPUT CONTRACTILITY Contraction force for a given preload Myocytes more responsive to stimulation Affected by Ca++ concentrations Increased by Epinephrine, Norepinephrine Glucagon, cAMP Digitalis CARDIAC OUTPUT : CARDIAC OUTPUT AFTERLOAD Blood pressure in arteries just outside of semilunar valves Increased afterload reduces stroke volume Resistance Caused by anything impeding arterial circulation CARDIAC OUTPUT : CARDIAC OUTPUT EFFECTS OF EXERCISE Increased cardiac output Ventricular hypertrophy Increased stroke volume Proprioreceptors More efficient signals from muscles / joints Increased venous return Increased preload