POWERPOINT LECTURE SLIDE PRESENTATION by LYNN CIALDELLA MBA

POWERPOINT® LECTURE SLIDE PRESENTATION by LYNN CIALDELLA, MBA, The University of Texas at Austin Additional Text by J Padilla exclusively for Physiology 31 at ECC UNIT 3 14 PART A Cardiovascular Physiology HUMAN PHYSIOLOGY AN INTEGRATED APPROACH DEE UNGLAUB SILVERTHORN Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings FOURTH EDITION

Structure of the Heart The heart valves ensure one-way flow Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -7 g

Heart Valves PLAY Animation: Cardiovascular System: Anatomy Review: The Heart Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -9

Heart Valves Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Histology of Myocardium § Involuntary muscle § Striated, has sarcomeres § Many mitochondria § Uni- or binucleated § Branched § Intercalated Disc § Rhythmic contractions § Does not fatigue as as skeletal easily § Does not have individual neuromuscular junctions § Independent contractions § Require high O 2 Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Cardiac Muscle versus Skeletal Muscle § Smaller and have single nucleus per fiber § Have intercalated disks § Desmosomes allow force to be transferred § Gap Junctions provide electrical connection § T-tubules are larger and branch § Sarcoplasmic reticulum is smaller § Mitochondria occupy one-third of cell volume Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Excitation-contraction coupling and relaxation in cardiac muscle Ca 2+ 1 1 Action potential enters from adjacent cell. ECF 2 Voltage-gated Ca 2+ channels open. Ca 2+ enters cell. ICF Ryanodine receptor-channel 2 3 SR Sarcoplasmic reticulum (SR) Ca 2+ 4 T-tubule Ca 2+ spark 5 3 Ca 2+ induces Ca 2+ release through ryanodine receptor-channels (Ry. R). 4 Local release causes Ca 2+ spark. 2+ 5 Summed Ca Sparks 2+ create a Ca signal. 2+ 6 Ca ions bind to troponin to initiate contraction. Ca 2+ signal 6 Contraction Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -11, steps 1– 6

Excitation-contraction coupling and relaxation in cardiac muscle Ca 2+ 1 1 Action potential enters from adjacent cell. ECF 2 Voltage-gated Ca 2+ channels open. Ca 2+ enters cell. ICF Ryanodine receptor-channel 3 Ca 2+ induces Ca 2+ release through ryanodine receptor-channels (Ry. R). 2 3 SR Sarcoplasmic reticulum (SR) Ca 2+ 4 T-tubule Ca 2+ stores 4 Local release causes Ca 2+ spark. 2+ 5 Summed Ca Sparks 2+ create a Ca signal. ATP Ca 2+ spark 8 Ca 2+ 2+ 6 Ca ions bind to troponin to initiate contraction. 5 7 Relaxation occurs when Ca 2+ unbinds from troponin. Ca 2+ signal Ca 2+ 6 Contraction 7 Relaxation Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Actin 2+ 8 Ca is pumped back into the sarcoplasmic reticulum for storage. Myosin Figure 14 -11, steps 1– 8

Excitation-contraction coupling and relaxation in cardiac muscle 9 Ca 2+ 1 ECF Ca 2+ 10 3 Na+ 1 Action potential enters from adjacent cell. 2 K+ ATP ICF Ryanodine receptor-channel 2 Voltage-gated Ca 2+ channels open. Ca 2+ enters cell. 3 Na+ Ca 2+ 3 Ca 2+ induces Ca 2+ release through ryanodine receptor-channels (Ry. R). 2 3 SR Sarcoplasmic reticulum (SR) Ca 2+ 4 T-tubule Ca 2+ stores 4 Local release causes Ca 2+ spark. 2+ 5 Summed Ca Sparks 2+ create a Ca signal. ATP Ca 2+ spark 8 Ca 2+ 2+ 6 Ca ions bind to troponin to initiate contraction. 5 Ca 2+ 7 Relaxation occurs when Ca 2+ unbinds from troponin. signal Ca 2+ 6 7 Actin 2+ 8 Ca is pumped back into the sarcoplasmic reticulum for storage. 9 Ca 2+ is exchanged with Na+. Contraction Relaxation Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Myosin 10 Na+ gradient is maintained by the Na+-K+-ATPase. Figure 14 -11, steps 1– 10

Myocardial Contractile Cells Action potential of a cardiac contractile cell +20 Na+ passes through double gated voltage channels Plateau results from decreased K+ and increased Ca++ Plateau end when flux is reversed 2 PK and PCa 0 Membrane potential (m. V) Resting membrane potential is -90 mv. PX = Permeability to ion X PNa 1 -20 -40 3 0 PNa -60 -80 PK and PCa 4 4 -100 0 Phase 100 200 Time (msec) 300 Membrane channels 0 Na+ channels open 1 Na+ channels close 2 Ca 2+ channels open; fast K+ channels close 3 Ca 2+ channels close; slow K+ channels open 4 Resting potential Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -13

Myocardial Contractile Cells Refractory periods and summation in skeletal and cardiac muscle- this prevents summation as it happens in skeletal muscle Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -14 c

Modulation of Heart Rate by the Nervous System Sympathetic stimulation targets If channels to open rapidly. Parasympathet ic stimuation targets K+ and Ca++ channels, it hyperpolarizes the cell and slows depolarization Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -16

Electrical Conduction in Myocardial Cells 1% of myocardial cells are designed to spontaneously generate an action potential. They can contract without outside signal= autorhythmic. Pacemaker cells do not have sarcomeres Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -17

Electrical Conduction in Heart SA node AV node 1 1 2 THE CONDUCTING SYSTEM OF THE HEART 1 SA node depolarizes. SA node 3 Internodal pathways 2 Electrical activity goes rapidly to AV node via internodal pathways. 3 Depolarization spreads more slowly across atria. Conduction slows through AV node A-V bundle Bundle branches 4 Purkinje fibers 4 Depolarization moves rapidly through ventricular conducting system to the apex of the heart. 5 Depolarization wave spreads upward from the apex. 5 Purple shading in steps 2– 5 represents depolarization. Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -18

Electrical Conduction & Einthoven’s Triangle § AV node § Direction of electrical signals § Delay the transmission of action potentials § SA node § Set the pace of the heartbeat at 70 bpm § AV node (50 bpm) and Purkinje fibers (25 -40 bpm) can act as pacemakers under some conditions Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Electrical Activity Comparison of an ECG and a myocardial action potential Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -22

The Electrocardiogram ECG give info on heart rate, heart rhythm, conduction velocity, and heart condition. Three major waves: P wave, QRS complex, and T wave Waves correspond to events of the cardiac cycle. Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -20

Electrical Activity Correlation between an ECG and electrical events in the heart P wave: atrial depolarization START P The end R PQ or PR segment: conduction through AV node and A-V bundle T P P QS Atria contract. T wave: ventricular Repolarization R T P ELECTRICAL EVENTS OF THE CARDIAC CYCLE QS P Q wave Q ST segment R R wave R P QS P R Ventricles contract. Q P S wave QS Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -21

Electrical Activity The P wave reflects the activity of the atria. The atria contract from top to bottom so the P-wave ends after full atrial depolarization P wave: atrial depolarization START P PQ or PR segment: conduction through AV node and A-V bundle P Atria contract. ELECTRICAL EVENTS OF THE CARDIAC CYCLE Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -21 (2 of 9)

Electrical Activity The P-Q segment reflects the flow of current along the interventricular septum via the AV node and AV bundle. This is the time when the ventricles are relaxed and filling with blood P wave: atrial depolarization START P PQ or PR segment: conduction through AV node and A-V bundle P Atria contract. ELECTRICAL EVENTS OF THE CARDIAC CYCLE Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings P Q wave Q Figure 14 -21 (3 of 9)

Electrical Activity The QRS complex occurs while the ventricles contraction (depolarize) from the apex & upwards. At the end of the contraction all blood volume to be expelled as been pushed out. S-T segment happens during ventricular repolarization (relax) P wave: atrial depolarization START P PQ or PR segment: conduction through AV node and A-V bundle P Atria contract. ELECTRICAL EVENTS OF THE CARDIAC CYCLE P Q wave Q ST segment R R wave R P QS P R Ventricles contract. Q P S wave QS Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -21 (6 of 9)

Electrical Activity The T-wave indicates ventricular repolarizationmeaning that the muscle is coming back to a resting state. At this point the chambers are ready to receive blood P wave: atrial depolarization START P The end R PQ or PR segment: conduction through AV node and A-V bundle T P P QS Atria contract. T wave: ventricular Repolarization R T P ELECTRICAL EVENTS OF THE CARDIAC CYCLE QS P Q wave Q ST segment R R wave R P QS P R Ventricles contract. Q P S wave QS Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -

Electrical Activity Normal and abnormal electrocardiograms Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -23

Mechanical Events Mechanical events of the cardiac cycle 1 START 5 Late diastole: both sets of chambers are relaxed and ventricles fill passively. Isovolumic ventricular relaxation: as ventricles relax, pressure in ventricles falls, blood flows back into cups of semilunar valves and snaps them closed. Ventricular ejection: 4 as ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected. Atrial systole: atrial contraction forces a small amount of additional blood into ventricles. 2 3 Isovolumic ventricular contraction: first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. PLAY Animation: Cardiovascular System: Cardiac Cycle Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -24

Mechanical Events 1 START Late diastole: both sets of chambers are relaxed and ventricles fill passively. 2 Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Atrial systole: atrial contraction forces a small amount of additional blood into ventricles. Figure 14 -24, steps 1– 2

Mechanical Events 1 START Late diastole: both sets of chambers are relaxed and ventricles fill passively. Atrial systole: atrial contraction forces a small amount of additional blood into ventricles. 2 3 Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Isovolumic ventricular contraction: first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. Figure 14 -24, steps 1– 3

Mechanical Events 1 START Late diastole: both sets of chambers are relaxed and ventricles fill passively. Atrial systole: atrial contraction forces a small amount of additional blood into ventricles. 2 Ventricular ejection: 4 as ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected. Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 3 Isovolumic ventricular contraction: first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. Figure 14 -24, steps 1– 4

Mechanical Events 1 START 5 Late diastole: both sets of chambers are relaxed and ventricles fill passively. Isovolumic ventricular relaxation: as ventricles relax, pressure in ventricles falls, blood flows back into cups of semilunar valves and snaps them closed. Ventricular ejection: 4 as ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected. Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Atrial systole: atrial contraction forces a small amount of additional blood into ventricles. 2 3 Isovolumic ventricular contraction: first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. Figure 14 -24, steps 1– 5

Cardiac Cycle Left ventricular pressure-volume changes during one cardiac cycle KEY EDV = End-diastolic volume ESV = End-systolic volume Stroke volume Left ventricular pressure (mm Hg) 120 D ESV 80 C One cardiac cycle 40 EDV B A 0 65 100 Left ventricular volume (m. L) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 135 Figure 14 -25

Cardiac Cycle At the beginning of the diastolic phase the ventricles are relax and contain a very small amount of blood KEY Left ventricular pressure (mm Hg) EDV = End-diastolic volume ESV = End-systolic volume 120 80 40 A 0 65 100 Left ventricular volume (m. L) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 135 Figure 14 -25 (1 of 4)

Cardiac Cycle At then of the diastolic phase the volume as increased because the ventricle has filled after the ventricles contracted KEY Left ventricular pressure (mm Hg) EDV = End-diastolic volume ESV = End-systolic volume 120 80 40 EDV A 0 65 100 Left ventricular volume (m. L) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings B 135 Figure 14 -25 (2 of 4)

Cardiac Cycle At point C (systole phase) the pressure has increased but the volume has not changed KEY EDV = End-diastolic volume ESV = End-systolic volume Left ventricular pressure (mm Hg) 120 80 C 40 EDV B A 0 65 100 Left ventricular volume (m. L) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings 135 Figure 14 -25 (3 of 4)

Cardiac Cycle At the end of systole the pressure is at is highest and the volume has dropped. Stroke volume= EDV - ESV KEY Left ventricular pressure (mm Hg) EDV = End-diastolic volume ESV = End-systolic volume Stroke volume 120 D ESV 80 C One cardiac cycle 40 EDV A 0 65 100 Left ventricular volume (m. L) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings B 135 Figure 14 -25 (4 of 4)

Wiggers Diagram This diagram shows the relationship between the cardiac cycle, the ECG, the heart sounds, and pressure changes in the left ventricle and aorta 0 Time (msec) 200 300 400 100 QRS complex Electrocardiogram (ECG) P 500 600 700 800 QRS complex Cardiac cycle T P 120 Pressure (mm Hg) 90 Aorta Dicrotic notch Left ventricular pressure 60 Left atrial 30 pressure Heart sounds Left ventricular volume (m. L) Atrial systole S 1 S 2 135 65 Atrial Ventricular systole Isovolumic Ventricular ventricular systole contraction Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Ventricular diastole Early ventricular diastole Atrial systole Late ventricular diastole Atrial systole Figure 14 -26

Wiggers Diagram This shows the correlation between the carciac cycle and the ECG. Notice between the T wave of one and P wave of another the ventricles are relaxed while the atria are filling and beginning to empty prior to atrial depolarization 0 Electrocardiogram (ECG) P 100 Time (msec) 200 300 400 QRS complex Isovolumic ventricular contraction Ventricular systole 600 700 800 QRS complex Cardiac cycle T P Atrial Ventricular systole Atrial systole 500 Ventricular diastole Early ventricular diastole Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Atrial systole Late ventricular diastole Atrial systole Figure 14 -26

Wiggers Diagram This phase shows the changes in blood volume as the ventricle contracts (depolarizes) or relaxes (repolarizes) 135 Left ventricular volume (m. L) Atrial systole 0 100 Time (msec) 200 300 400 500 600 700 800 65 Isovolumic ventricular contraction Atrial Ventricular systole Ventricular diastole Early ventricular diastole Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Atrial systole Late ventricular diastole Atrial systole Figure 14 -26

Wiggers Diagram You can see the relationship between pressure chages in teh atrium and the cardiac cycle. Notice that the lowest atrial pressure is during ventricular diastole. 0 Pressure (mm Hg) 100 Time (msec) 200 300 400 500 600 700 800 90 60 30 Left atrial pressure Left ventricular volume (m. L) 135 65 Atrial Ventricular systole Ventricular diastole Isovolumic Early Atrial systole Ventricular ventricular systole Cummings Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin contraction diastole Atrial systole Late ventricular diastole Atrial systole. Figure 14 -26

Wiggers Diagram This shows changes in ventricular pressure and valve sounds as the AV valve (S 1) and semilunar valves (S 2) close. 0 Time (msec) 200 300 400 100 500 600 700 800 120 Pressure (mm Hg) 90 60 Left ventricular pressure 30 Heart sounds Atrial systole S 1 135 Isovolumic ventricular contraction S 2 Atrial Ventricular systole Ventricular diastole Early ventricular diastole Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Atrial systole Late ventricular diastole Atrial systole Figure 14 -26

Wiggers Diagram This shows changes in ventricular pressure and ventricular blood volume. 0 Pressure (mm Hg) 100 Time (msec) 200 300 400 500 600 700 800 90 60 30 135 Left ventricular volume (m. L) 65 Left ventricular pressure S 1 S 2 Atrial Ventricular systole Atrial systole Isovolumic ventricular contraction Ventricular systole Ventricular diastole Early ventricular diastole Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Atrial systole Late ventricular diastole Atrial systole Figure 14 -26

Wiggers Diagram The top line shows changes in pressure of the aorta as the left ventricle contracts or relaxes. The dicrotic notch occurs as a sharp drop in pressure results from a drop in blood flow once the ventricle begins to relax 0 Time (msec) 200 300 400 100 500 600 700 800 120 Pressure (mm Hg) 90 60 Aorta Dicrotic notch Left ventricular pressure 30 Heart sounds S 1 S 2 Atrial Ventricular systole Atrial systole Isovolumic ventricular contraction Ventricular systole Ventricular diastole Early ventricular diastole Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Atrial systole Late ventricular diastole Atrial systole Figure 14 -26

Wiggers Diagram 0 Time (msec) 200 300 400 100 500 600 700 800 120 Pressure (mm Hg) 90 Aorta Dicrotic notch Left ventricular pressure 60 Left atrial 30 pressure Heart sounds S 1 S 2 Atrial Ventricular systole Atrial systole Isovolumic ventricular contraction Ventricular systole Ventricular diastole Early ventricular diastole Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Atrial systole Late ventricular diastole Atrial systole Figure 14 -26

Wiggers Diagram 0 Electrocardiogram (ECG) This shows all the events that are happening during one complete ECG wave Time (msec) 200 300 100 P QRS complex T 120 Pressure (mm Hg) 90 Aorta Left ventricular pressure 60 Left atrial 30 pressure Heart sounds Left ventricular volume (m. L) S 1 135 65 Atrial Ventricular systole Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -26

Wiggers Diagram 0 This shows all the changes happening during ventricular diastole Electrocardiogram (ECG) Time (msec) 200 300 400 100 P QRS complex 500 600 700 800 Cardiac cycle T 120 Pressure (mm Hg) 90 Aorta Dicrotic notch Left ventricular pressure 60 Left atrial 30 pressure Heart sounds Left ventricular volume (m. L) S 1 S 2 135 65 Atrial Ventricular systole Ventricular diastole Late ventricular diastole Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 14 -26

Wiggers Diagram 0 Electrocardiogram (ECG) These are all the events during one complete cardiac cycle Time (msec) 200 300 400 100 P QRS complex 500 600 700 800 QRS complex Cardiac cycle T P 120 Pressure (mm Hg) 90 Aorta Dicrotic notch Left ventricular pressure 60 Left atrial 30 pressure Heart sounds Left ventricular volume (m. L) Atrial systole S 1 S 2 135 65 Atrial Ventricular systole Isovolumic ventricular contraction Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Ventricular systole Ventricular diastole Early ventricular diastole Atrial systole Late ventricular diastole Atrial systole Figure 14 -26