Power Point Lecture Slide Presentation by Patty BostwickTaylor
Power. Point® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College The Cardiovascular System Cardiac Cycle & Cardiac Output 11 PART A Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
The Heart: Cardiac Cycle § Atria contract simultaneously § Atria relax, then ventricles contract § Systole = contraction § Diastole = relaxation Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings • “Sisters work while Dad sleeps” • To die is as relaxed as you can get.
Filling Heart Chambers: Cardiac Cycle § Cardiac cycle —events of one complete heart beat Left atrium Right atrium Left ventricle Right ventricle Ventricular filling Atrial contraction Mid-to-late diastole (ventricular filling) Isovolumetric Ventricular contraction phase ejection phase Isovolumetric relaxation Ventricular systole (atria in diastole) Early diastole Figure 11. 7 Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
Filling Heart Chambers: Cardiac Cycle Left atrium Right atrium Left ventricle Right ventricle Ventricular filling Mid-to-late diastole (ventricular filling) § Mid-to-late diastole —blood flows from atria into ventricles Figure 11. 7, step 1 a Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
Filling Heart Chambers: Cardiac Cycle Left atrium Right atrium Left ventricle Right ventricle Ventricular filling Atrial contraction Mid-to-late diastole (ventricular filling) § Mid-to-late diastole —blood flows from atria into ventricles Figure 11. 7, step 1 b Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
Filling Heart Chambers: Cardiac Cycle Left atrium Right atrium Left ventricle Right ventricle Ventricular filling Atrial contraction Mid-to-late diastole (ventricular filling) Isovolumetric contraction phase Ventricular systole (atria in diastole) § Ventricular systole —blood pressure builds before ventricle contracts, pushing out blood Figure 11. 7, step 2 a Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
Filling Heart Chambers: Cardiac Cycle Left atrium Right atrium Left ventricle Right ventricle Ventricular filling Atrial contraction Mid-to-late diastole (ventricular filling) Isovolumetric Ventricular contraction phase ejection phase Ventricular systole (atria in diastole) § Ventricular systole —blood pressure builds before ventricle contracts, pushing out blood Figure 11. 7, step 2 b Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
Filling Heart Chambers: Cardiac Cycle Left atrium Right atrium Left ventricle Right ventricle Ventricular filling Atrial contraction Mid-to-late diastole (ventricular filling) Isovolumetric Ventricular contraction phase ejection phase Isovolumetric relaxation Ventricular systole (atria in diastole) Early diastole § Early diastole —atria finish refilling, ventricular pressure is low Figure 11. 7, step 3 Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
The Heart: Heart Sounds 1. “lub” § AV valves close § Longer & louder 2. “dup” § Semilunar valves close § Shorter & sharper 3. Pause 4. Repeat Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
The Heart: Cardiac Output § Cardiac output (CO) § Amount of blood pumped by each side (ventricle) of the heart in one minute § Stroke volume (SV) § Volume of blood pumped by each ventricle in one contraction (each heartbeat) § Usually remains relatively constant § About 70 m. L of blood is pumped out of the left ventricle with each heartbeat § Heart rate (HR) § Typically 75 beats per minute Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
The Heart: Cardiac Output § CO = HR SV § CO = HR (75 beats/min) SV (70 m. L/beat) § CO = 5250 m. L/min (the body’s entire blood supply passes through the heart each minute…) § Starling’s law of the heart —the more the cardiac muscle is stretched before a contraction, the stronger the contraction § Changing heart rate is the most common way to change cardiac output Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
The Heart: Regulation of Heart Rate § Increased heart rate 1. Sympathetic nervous system § Crisis § Low blood pressure 2. Hormones § Epinephrine § Thyroxine 3. Exercise 4. Decreased blood volume Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
The Heart: Regulation of Heart Rate § Decreased heart rate 1. Parasympathetic nervous system 2. High blood pressure or blood volume 3. Increased venous return (typo: not decreased) Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
Cardiac Output Regulation Figure 11. 8 Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings
- Slides: 14