1. The Cardiovascular System

2. Mid Session Quiz -25% Next week Will be on WebCT From 5pm 21/8/07  5 pm 24/8/07 Multiple choice and matching Covers all lecture, lab and reading materials from weeks 1-5 Time limit = ½ hour Grades and feedback will be released automatically

3. Design of lab Due in labs week 5 (Cut-off 24/8/07) Template on WebCT Resources  see zali Submit –1 hard copy per group –and email digital copy to Zali

4. Labs 1-5 Due by 31/8/07 Submit lab book in labs week 6 Cut-off date 31/8/07

5. Cardiovascular System Chapter 10 of text

6. Major Cardiovascular Functions Delivers oxygen to active tissues Aerates blood returned to the lungs Transports heat, a byproduct of cellular metabolism, from the body’s core to the skin Delivers fuel nutrients to active tissues Transports hormones, the body’s chemical messengers

7. CV system Consists of; –Blood ~ 5L / 8% body mass –Heart- pump –Arteries- High pressure transport –Capillaries- Exchange vessels –Veins- Low pressure transport

9. Grey’s Anatomy Left Ventricular Assist Device (LVAD)

11. Peripheral Vasculature Arteries –Provides the high- pressure tubing that conducts oxygenated blood to the tissues Capillaries –Site of gas, nutrient, and waste exchange Veins –Provides a large systemic blood reservoir and conducts deoxygenated blood back to the heart

13. Blood Pressure Systolic blood pressure –Highest arterial pressure measured after left ventricular contraction (systole) –e.g., 120 mm Hg Diastolic blood pressure –Lowest arterial pressure measured during left ventricular relaxation (diastole) –e.g., 80 mm Hg

16. Heart Rate Regulation Cardiac muscle possesses intrinsic rhythmicity Without external stimuli, the adult heart would beat steadily between 50 and 80 times each minute

17. Regulation of HR Sympathetic influence –Catecholamine (NE/E) –Results in tachycardia Parasympathetic influence –Acetylcholine –Results in bradycardia Cortical influence – Anticipatory heart rate

18. CV system during exercise Acute Adaptations

19. Cardiovascular Dynamics Q = HR × SV (Fick Equation) –Q: cardiac output –HR: heart rate –SV: stroke volume

20. Cardiac Output At Rest –Q = 5 L p/Min Trained RHR = 50 bpm, SV = 71 Untrained RHR = 70 bpm, SV = 100 During Exercise –Untrained- Q = 22 000 mL p/min, MHR = 195 »SV av 113 ml blood p/beat –Trained- Q= 35 000 ml p/min, MHR = 195 »SV av 179 ml blood p/beat Q = HR × SV

21. Increases in Stroke Volume Increased ability to fill ventricles More forceful contraction to pump blood out Training adaptations –Increased blood volume –Reduced resistance to blood flow

22. Cardiac output distribution

23.  Oxygen Consumption  Oxygen Extraction  Muscle Blood Flow  a-vO 2   Cardiac Output  Stroke Volume  Heart Rate  End Diastolic Volume  Venous Return  Muscle Contraction  Contractility  Cellular Respiration  Muscle Vascular Resistance Figure 7.16 Sympathetic Stimulation

24. Oxygen transport 1 litre blood carries 200 ml oxygen During exercise –Q = 22L p /min = 4.4L oxygen per minute At rest –Q = 5L p/ min = 1 L oxygen per minute 250 ml required at rest Remainder- oxygen reserves

25. Cardiovascular Adaptations to Exercise Chronic Adaptations Pg 441-446 in text

26. Chronic Adaptations to Exercise Cardiovascular adaptations to training are extremely important for improving endurance exercise performance, and preventing cardiovascular diseases. The more important of these adaptations are,   Size of heart  ventricular volumes ¤  total blood volume -  plasma volume -  red cell mass ¤  systolic and diastolic blood pressures ¤  maximal stroke volume ¤  maximal cardiac output ¤  extraction of oxygen

27. Training Adaptations: Heart Eccentric hypertrophy –Slight thickening in left ventricle walls –Increases left ventricular cavity size Therefore increases stroke volume

28. Total Blood Volume * Plasma volume -4 training sessions can increase plasma volume by 20% *Increased RBC - Number of RBC increases, but due to increase in Plasma volume, concentration stays the same

29. Heart Rate Elite athletes have a lower heart rate relative to training intensity than sedentary people

30. Saltin, 1969 Endurance athletes Sedentary college BEFORE 55 day aerobic training program Sedentary college AFTER

31. Stroke Volume and Cardiac Output Exercise  increases stroke volume during rest and exercise Slight decrease heart rate Increase in cardiac output comes from increased stroke volume

32. Blood Pressure Aerobic exercise reduces systolic and diastolic BP at rest and during exercise Particularly systolic –Caused by decrease in catecholamines Another reason for exercise to be prescribed for those with hypertension Resistance training not recommended due to acute high BP it causes

33. Oxygen Extraction Training increases quantity of O2 that can be extracted during exercise

34. Explain… Why is there a difference in the Vo2 max of Jana Pittman and Kimberly Kim??  TRAINING! What Chronic cardiovascular adaptations to training would have increased Vo2 max?

35. Exercise to VO 2 maxSubmaximal Steady State Exercise  VO 2 max  Oxygen Delivery  Maximal Muscle Blood Flow  Maximal Cardiac Output  Maximal Stroke Volume  End Diastolic Volume  Muscle Capillary Density  Venous Return  Ventricular Volume  Blood Volume  Plasma Volume  Red Cell Mass Training For Long-Term Endurance  Sympathetic Stimulation  End Diastolic Volume  Venous Return  Blood Volume  Plasma Volume  Red Cell Mass  Ventricular Volume  Stroke Volume  Heart Rate Training For Long-Term Endurance

36. Chronic Adaptations to Exercise The more important of these adaptations are, ¤Increased size of heart  ventricular volumes ¤  total blood volume -  plasma volume -  red cell mass ¤  systolic and diastolic blood pressures ¤  maximal stroke volume ¤  maximal cardiac output ¤  extraction of oxygen

37. Factors Affecting Chronic adaptations Initial CV fitness Training: –Frequency- 3 x p/week Only slightly higher gains for 4 or 5 times p/week –Intensity Most critical Minimum is 130/ 140 bpm = (av) 50-55% Vo2 max/ 70% HR max Higher = better –Time Or duration- 30 min is minimum –Type Specificity

38. Summary Need to know –Cardiac Structure and Function Veins/arteries/cappilaries –Flow of blood through the heart –Acute adaptations to exercise –Chronic adaptations to exercise