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POWERPOINT ® LECTURE SLIDE PRESENTATION by LYNN CIALDELLA, MA, MBA, The University of Texas at Austin Additional Text by J Padilla exclusively for Physiology.

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Presentation on theme: "POWERPOINT ® LECTURE SLIDE PRESENTATION by LYNN CIALDELLA, MA, MBA, The University of Texas at Austin Additional Text by J Padilla exclusively for Physiology."— Presentation transcript:

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

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

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

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

5 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 easily as skeletal  Does not have individual neuromuscular junctions  Independent contractions  Require high O2

6 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

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

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

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

10 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Myocardial Contractile Cells Action potential of a cardiac contractile cell PhaseMembrane channels P X = Permeability to ion X Membrane potential (mV) Time (msec) P K and P Ca P Na P K and P Ca P Na Na + channels open Na + channels close Ca 2+ channels open; fast K + channels close Ca 2+ channels close; slow K + channels open Resting potential Resting membrane potential is -90mv. Na+ passes through double gated voltage channels Plateau results from decreased K+ and increased Ca++ Plateau end when flux is reversed Resting membrane potential is -90mv. Na+ passes through double gated voltage channels Plateau results from decreased K+ and increased Ca++ Plateau end when flux is reversed

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

12 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 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 hyper- polarizes the cell and slows depolarization Sympathetic stimulation targets If channels to open rapidly. Parasympathet ic stimuation targets K+ and Ca++ channels, it hyper- polarizes the cell and slows depolarization

13 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 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 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

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

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

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

17 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 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.

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

19 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (2 of 9) Electrical Activity P wave: atrial depolarization START Atria contract. PQ or PR segment: conduction through AV node and A-V bundle P ELECTRICAL EVENTS OF THE CARDIAC CYCLE P 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

20 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (3 of 9) Electrical Activity P wave: atrial depolarization START Atria contract. PQ or PR segment: conduction through AV node and A-V bundle P P Q Q wave ELECTRICAL EVENTS OF THE CARDIAC CYCLE P 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

21 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (6 of 9) Electrical Activity P wave: atrial depolarization START Atria contract. PQ or PR segment: conduction through AV node and A-V bundle P P Q Q wave R wave P Q R S wave QSQS R P ELECTRICAL EVENTS OF THE CARDIAC CYCLE ST segment Ventricles contract. P Q R S P 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) 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)

22 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (9 of 9) Electrical Activity P wave: atrial depolarization P START Atria contract. PQ or PR segment: conduction through AV node and A-V bundle P P Q Q wave R wave P Q R S wave QSQS R P ELECTRICAL EVENTS OF THE CARDIAC CYCLE Repolarization ST segment Ventricles contract. P Q R S The end T wave: ventricular Repolarization P QSQS R T P QSQS R T The T-wave indicates ventricular repolarization- meaning that the muscle is coming back to a resting state. At this point the chambers are ready to receive blood

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

24 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Mechanical Events Mechanical events of the cardiac cycle Animation: Cardiovascular System: Cardiac Cycle PLAY 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. Isovolumic ventricular contraction: first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. Isovolumic ventricular relaxation: as ventricles relax, pressure in ventricles falls, blood flows back into cups of semilunar valves and snaps them closed. Ventricular ejection: as ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected

25 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 14-24, steps 1–2 Mechanical Events START 1 2 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.

26 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 14-24, steps 1–3 Mechanical Events 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. Isovolumic ventricular contraction: first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves.

27 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 14-24, steps 1–4 Mechanical Events 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. Isovolumic ventricular contraction: first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. Ventricular ejection: as ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected.

28 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 14-24, steps 1–5 Mechanical Events 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. Isovolumic ventricular contraction: first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. Isovolumic ventricular relaxation: as ventricles relax, pressure in ventricles falls, blood flows back into cups of semilunar valves and snaps them closed. Ventricular ejection: as ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected.

29 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Cardiac Cycle Left ventricular pressure-volume changes during one cardiac cycle A B C Left ventricular volume (mL) EDV ESV D Stroke volume KEY EDV = End-diastolic volume ESV = End-systolic volume One cardiac cycle Left ventricular pressure (mm Hg)

30 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (1 of 4) Cardiac Cycle A Left ventricular volume (mL) KEY EDV = End-diastolic volume ESV = End-systolic volume Left ventricular pressure (mm Hg) At the beginning of the diastolic phase the ventricles are relax and contain a very small amount of blood

31 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (2 of 4) Cardiac Cycle A B Left ventricular volume (mL) EDV KEY EDV = End-diastolic volume ESV = End-systolic volume Left ventricular pressure (mm Hg) At then of the diastolic phase the volume as increased because the ventricle has filled after the ventricles contracted

32 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (3 of 4) Cardiac Cycle A B C Left ventricular volume (mL) Left ventricular pressure (mm Hg) EDV KEY EDV = End-diastolic volume ESV = End-systolic volume At point C (systole phase) the pressure has increased but the volume has not changed

33 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (4 of 4) Cardiac Cycle A B C Left ventricular volume (mL) EDV ESV D Stroke volume KEY EDV = End-diastolic volume ESV = End-systolic volume One cardiac cycle Left ventricular pressure (mm Hg) At the end of systole the pressure is at is highest and the volume has dropped. Stroke volume= EDV - ESV

34 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Electro- cardiogram (ECG) Pressure (mm Hg) Heart sounds Left ventricular volume (mL) Dicrotic notch P Cardiac cycle Atrial systole Atrial systole Ventricular systole Ventricular diastole P T S2S2 S1S1 Atrial systoleVentricular systole Early ventricular diastole Late ventricular diastole Atrial systole Isovolumic ventricular contraction Left ventricular pressure Left atrial pressure Time (msec) Aorta QRS complex QRS complex This diagram shows the relationship between the cardiac cycle, the ECG, the heart sounds, and pressure changes in the left ventricle and aorta

35 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Electro- cardiogram (ECG) P Cardiac cycle Atrial systole Atrial systole Ventricular systole Ventricular diastole P T Atrial systoleVentricular systole Atrial systole Time (msec) Early ventricular diastole Late ventricular diastole Isovolumic ventricular contraction QRS complex QRS complex 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

36 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Left ventricular volume (mL) Atrial systole Atrial systole Ventricular systole Ventricular diastole Atrial systoleVentricular systole Atrial systole Time (msec) Early ventricular diastole Late ventricular diastole Isovolumic ventricular contraction This phase shows the changes in blood volume as the ventricle contracts (depolarizes) or relaxes (repolarizes)

37 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Pressure (mm Hg) Left ventricular volume (mL) Atrial systole Atrial systole Ventricular systole Ventricular diastole Atrial systoleVentricular systole Atrial systole Left atrial pressure Time (msec) Early ventricular diastole Late ventricular diastole Isovolumic ventricular contraction 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.

38 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Pressure (mm Hg) Heart sounds Atrial systole Atrial systole Ventricular systole Ventricular diastole S2S2 S1S1 Atrial systoleVentricular systole Atrial systole Left ventricular pressure Time (msec) Early ventricular diastole Late ventricular diastole Isovolumic ventricular contraction This shows changes in ventricular pressure and valve sounds as the AV valve (S1) and semilunar valves (S2) close.

39 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Pressure (mm Hg) Left ventricular volume (mL) Atrial systole Atrial systole Ventricular systole Ventricular diastole S2S2 S1S1 Atrial systoleVentricular systole Atrial systole Left ventricular pressure Time (msec) Early ventricular diastole Late ventricular diastole Isovolumic ventricular contraction This shows changes in ventricular pressure and ventricular blood volume.

40 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Pressure (mm Hg) Heart sounds Dicrotic notch Atrial systole Atrial systole Ventricular systole Ventricular diastole S2S2 S1S1 Atrial systoleVentricular systole Atrial systole Left ventricular pressure Aorta Time (msec) Early ventricular diastole Late ventricular diastole Isovolumic ventricular contraction 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

41 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Pressure (mm Hg) Heart sounds Dicrotic notch Atrial systole Atrial systole Ventricular systole Ventricular diastole S2S2 S1S1 Atrial systoleVentricular systole Atrial systole Left ventricular pressure Left atrial pressure Aorta Time (msec) Early ventricular diastole Late ventricular diastole Isovolumic ventricular contraction

42 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Electro- cardiogram (ECG) Pressure (mm Hg) Heart sounds Left ventricular volume (mL) P Atrial systole Ventricular systole T S1S1 Ventricular systole Left ventricular pressure Left atrial pressure Time (msec) Aorta QRS complex This shows all the events that are happening during one complete ECG wave

43 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Electro- cardiogram (ECG) Pressure (mm Hg) Heart sounds Left ventricular volume (mL) Dicrotic notch P Cardiac cycle Atrial systole Ventricular systole Ventricular diastole T S2S2 S1S1 Left ventricular pressure Left atrial pressure Time (msec) Aorta Late ventricular diastole QRS complex This shows all the changes happening during ventricular diastole

44 Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Wiggers Diagram Electro- cardiogram (ECG) Pressure (mm Hg) Heart sounds Left ventricular volume (mL) Dicrotic notch P Cardiac cycle Atrial systole Atrial systole Ventricular systole Ventricular diastole P T S2S2 S1S1 Atrial systole Ventricular systole Atrial systole Left ventricular pressure Left atrial pressure Time (msec) Aorta Early ventricular diastole Late ventricular diastole Isovolumic ventricular contraction QRS complex QRS complex These are all the events during one complete cardiac cycle


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