Chapter 20 Heart For these questions use pages p 741 745 of course your lecture notes for lecture 8 Study Questions Lecture 8 1 Why is it important that the body can alter its cardiac output CO 2 Describe in your own words what cardiac output is Why is cardiac output something we discuss 3 How do extrinsic mechanisms nervous system endocrine system affect CO How can the heart intrinsically without neural or endocrine activity alter its cardiac output think about the effects of cardiac muscle sarcomere length Big Picture Details 4 How do we calculate CO What is the equation that describes CO How can we alter cardiac output generally all the following questions ask specifically If someone has a low heart rate HR why will their CO still be normal a Their SV could be increased 5 What is the primary intrinsic controller of stoke volume Frank Starling Law of the Heart How does this control stroke volume by what mechanism what is the name of the law Frank starling law What is the relevance of this in relation to congestive heart failure If the heart cannot pump out the amount of blood fast enough pulmonary edema can occur a What is the most important factor controlling CO cardiac output in the normal non exercising or lightly exercising individual Venous return 6 What other things affect SV Contractility and the amount of pressure in aorta and pulmonary trunk Does an increase in contractility affect ESV or EDV Does an increase in afterload affect ESV or EDV Know how changes in EDV or ESV will affect SV Contractility changes ESV because it pumps out more blood per beat 7 How does sympathetic output affect cardiac output Increases cardiac output What part of the brainstem controls autonomic signals outflow to the heart Medulla oblongata What center in the medulla oblongata controls sympathetic outflow to the heart Cardiovascular center How does this sympathetic outflow to the heart affect heart rate know the effect not the mechanism Increases heart rate How does the Bainbridge atrial reflex involve sympathetic fibers to the heart What is the Bainbridge reflex Receptors in the right atrium detects increased volume and sends a signal to the cardioacceleratory center which triggers an increased sympathetic activity in the SA node 8 What center in the medulla oblongata controls parasympathetic outflow to the heart Cardioinhibitory center of the heart How does this parasympathetic outflow to the heart affect heart rate know the effect not the mechanism Decreases heart rate How does increased parasympathetic outflow to the heart affect cardiac output Decreases CO What nerves carry the parasympathetic outflow to the heart Vagus Nerve Which of sympathetic or parasympathetic outflow dominates the heart at rest Parasympathetic 9 Summarize all the effects of increased venous return on the heart Increase in SV and CO Increase in HR and CO 10 Summarize all the effects of increased sympathetic stimulation on the heart