BIO 241 1st Edition Lecture 7Outline of Last Lecture I. Cardiac cycle 1II. Cardiac cycle 2III. Ventricular fillingIV. Isovolumetric contractionV. Ventricular ejectionVI. Isovolumetric relaxationVII. Overview of volume changesVIII. Timing of cardiac cycleOutline of Current LectureIX. Cardiac outputX. Cardiac reserveXI. Autonomic regulation of heart rateXII. Chemical regulation of heart rateCurrent LectureIX. The cardiac output is the amount of blood ejected from the left ventricle into the aorta per minute and the blood ejected from the right ventricle into the pulmonary trunk. That is the principal determinant of blood pressure. Cardiac output is determined by two factors: stroke volume and heart rate. CO = SV x HR. Therefore, CO = 70 mL/beat x 75 beats/minute. CO is on average 5.25 L/min. X. The cardiac reserve is the difference between the maximum CO and resting CO. It is expressed as a percentage above normal. Normal CO = 5 L/min. 100% of 5 is 5 – that’s 10 L total100% of 5 is 5 – that’s now 15 L totalCardiac reserve = 200%A well-trained endurance athlete may have a cardiac reserve of 35 L/min or 600% of normal.XI. The autonomic (involuntary) regulation of the heart is aided by sensory input. There are receptors within the heart and some blood vessels. Baroreceptors detect blood pressure in These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.certain places such as the aorta. There are also chemoreceptors that detect oxygen, carbon dioxide, and hydrogen ions. These sensory inputs go to the cardiovascular center of the medulla. From there, the signal becomes a motor output where the cardioacceleratory neurons control the sympathetics of the heart which usually means increasing heart rate and in turn increasing blood pressure. If blood pressure needs to decrease, cardioinhibitory neurons controlthe parasympathetics. XII. There are two broad types of chemicals that regulate the heart rate. The first type is hormones such as epinephrine, norepinephrine, thyroxine, glucagon which increase heart rate. The second is ions such as increased K+ which decreases heart rate or a moderate increase in Ca2+ which increases heart rate. The carotid and aortic sinus reflex raises heart rate as
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