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Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition.

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Presentation on theme: "Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition."— Presentation transcript:

1 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Chapter 16 Cardiovascular Regulation and Integration

2 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Intrinsic Regulation of Heart Rate Cardiac muscle has an inherent rhythm. The sinoatrial node –Would generate a rate ~ 100 BPM –Described as pacemaker

3 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Heart’s Electrical Activity Electrochemical rhythms spread from SA node across atria to atrioventricular (AV) node. AV node causes a slight delay of ~ 0.1 s. –Allows ventricles to fill AV bundle (bundle of His) –Right and left bundle branches –Purkinje system

4 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

5 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Electrocardiogram (ECG) A recording of the heart’s electrical activity A standard system of lead placement has established known wave patterns. –P wave –QRS complex –T wave

6 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Extrinsic Regulation of Heart Rate and Circulation Chemical: circulate via blood Neural: direct innervation

7 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Sympathetic and Parasympathetic Neural Input Operate in parallel Different structure pathways and transmitters

8 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Sympathetic Influence Catecholamines –Chronotropic: increases rate –Inotropic: decreases rate Adrenergic fibers

9 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

10 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Parasympathetic Influence Vagus nerves: cholinergic fibers –Release ACh –Slow HR As exercise begins, there is a decrease in parasympathetic activity.

11 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Input from Higher Centers Central command: coordinates neural activity to regulate flow to match demands

12 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

13 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

14 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Peripheral Input Chemoreceptors –Monitor metabolites, blood gases Mechanoreceptors –Monitor movement and pressure Baroreceptors –Monitor blood pressure in arteries

15 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Carotid Artery Palpation HR is often monitored using the carotid arteries. Pressure on baroreceptors may decrease HR. Alternatives include –HR monitor –Radial or temporal pulse

16 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Distribution of Blood Predominantly directed by –Vasodilation –Vasoconstriction

17 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Physical Factors Affecting Blood Flow Flow = Pressure gradient × Vessel radius 4 Vessel length × Viscosity

18 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Effect of Exercise At the start of exercise –Dilation of local arterioles –Vessels to nonactive tissues constrict

19 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Effect of Exercise At rest, only 1 of every 30 – 40 capillaries is open in skeletal muscle. During exercise, capillaries open and increase perfusion and O 2 delivery. Vasodilation mediated by – Temp – pH – CO 2 – Adenosine – NO – K + – MG +

20 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Nitric Oxide (NO) Produced and released by vascular endothelium NO spreads through cell membranes to muscle within vessel walls, causing relaxation. Net result is vasodilation.

21 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition

22 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Hormonal Factors Adrenal medulla releases –Epinephrine –Norepinephrine Cause vasoconstriction –Except in coronary arteries and skeletal muscles Minor role during exercise

23 Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Exercising After Cardiac Transplantation Depressed cardiac output Increased stroke volume


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