1. The Ventilatory and Cardiovascular Systems
Exercise Physiology
The Ventilatory and Cardiovascular Systems

2. I. Structure of the Ventilatory System
A. Conducting Airways:
*offers a low resistance pathway for air flow
*warms and moistens air
*mucus and ciliated cells filter air

3. II. Pulmonary Ventilation: the exchange of air between the atmosphere and lungs.
A. Mechanics of Breathing:
1. Inhalation:
*diaphragm contracts and lowers
*chest cavity expands increasing volume and decreasing internal air pressure

4. 2. Exhalation: *Diaphragm relaxes and moves up.
*chest cavity volume decreases and internal air pressure increases.
*during exercise the intercostal and abdominal muscles act on the ribs to produce greater exhalation

5. III. Total Lung Capacity: (TLC) maximum volume of lungs after maximum inhalation (vital capacity + residual vol.).
Tidal Vol.: (TV) volume inspired or expired per breath.
Inspiratory Reserve Vol.: max. inspiration at the end of tidal inspiration
(Vital cap.= TV+IRV+ERV)

6. C. Expiratory Reserve Vol. : max
C. Expiratory Reserve Vol.: max. expiration at the end of tidal expiration.
D. Residual Vol.: (RV) volume in lungs after maximum expiration.

7. IV. CO2 transport in the blood:
Dissolved directly in plasma
Bound to hemoglobin (carbamino compunds)
As bicarbonate
HCO3

8. D. What’s the role of CO2 in the control of pulmonary ventilation during exercise?
*dissociation of carbonic acid increases H+ in blood lowering pH.
*the medulla senses the low pH and sends signals to the diaphragm and intercostal muscles.

9. V. Oxygen Transport in the Blood:
Hemoglobin: (Hb) iron containing pigment that binds with oxygen to form oxyhemoglobin.
Hb + 4 O Hb4O8

10. VI. Gas Exchange in the lungs:
Alveoli: thin membrane sacs at the end of the bronchioles.
*serve as the site of gas exchange by diffusion.

11. VII. Blood: transport vehicle for nutrients, hormones, waste products and electrolytes.
1. Blood Composition:
A. Cellular:
i. erythrocytes: (RBC’s)
Contain hemoglobin that binds to oxygen for transport to tissues.

12. ii. Leukocytes: (WBC’s) defend the body against disease.
*produce antibodies
*destroy bacteria and viruses
*produce marker proteins

13. iii. Platelets: (thrombocytes) play a role in the clotting of blood.

14. B. Liquid Component:
i. Plasma: 60% total volume of blood. 90% water and 10% solutes
Metabolites and wastes (gases, hormones, vitamins)
Salts (ions)
Plasma proteins

15. VII. Anatomy of the Heart

16. A. Heart Rate: is regulated by both intrinsic and extrinsic factors.
Intrinsic regulation:
a. sinoatrial (S-A) node: a mass of specialized cardiac muscle located on the exterior wall of the right atrium. Initiates the electrical impulse.

17. b. Atrioventricular (A-V) node: receives impulse from the S-A node and delays it about .10 sec. for atrial contraction.
c. A-V Bundle of His: speeds the impulse over the ventricles to the Purkinje system causing simultaneous contraction of the ventricles.

18. ii. Extrinsic Regulation: the autonomic nervous system can override the myocardial rhythm.
Sympathetic Influence: epinephrine is released when stimulated causing heart rate to increase.
Parasympathetic Inf: releases acetylcholine to slow heart rate.

19. B. Circulation of Blood:
i. Pulmonary Circulation: deoxygenated blood is pumped from the right side of the heart through the pulmonary arteries to the lungs. Oxygenated blood is returned by the pulmonary veins.

20. ii. Systemic Circulation: oxygen rich blood is pumped from the left side of the heart through the aorta to the rest of the body.

21. iii. Cardiac Output: the volume of blood pumped by the heart in one minute. Equal to stroke vol. x heart rate.
Stroke Vol.: the volume of blood pumped by one ventricle with each beat. Approx. 70 ml.
Stroke vol.=EDV-ESV

22. iv. Cardiovascular Drift: an increase in heart rate during steady exercise due to a reduction in stroke volume.
Caused by:
*exercising in heat
*rise in core temp.
*decrease in plasma vol.

23. C. Blood Pressure: the pressure exerted on the walls of the arterial system.
Systole: highest pressure generated by the left ventricular contraction. Approx. 120 mm Hg at rest.
Diastole: the pressure generated when the heart relaxes. Approx mm Hg.

24. iii. Blood Pressure Response to Exercise:
Dynamic Exercise: systolic pressure increases with intensity with relatively little change in diastolic pressure.
Ex. Walking, jogging, swimming, cycling.

25. b. Static Exercise: heavy resistance training increases blood pressure due to muscular contractions compressing peripheral arteries.
Ex. Weightlifting, isometrics

26. iv. Distribution of Blood
Rest (cardiac output 5,000 ml)
*liver = 1350 ml
*kidneys = 1100 ml
*muscle = 1000 ml
*brain = 700 ml
*skin = 300 ml
*heart = 200 ml
Exercise (cardiac output 25,000 ml)
*liver = 500 ml
*kidneys = 250 ml
*muscle = 21,000 ml
*brain = 900 ml
*skin = 600 ml
*heart = 1000 ml

29. v. Cardiovascular Adaptations to Exercise:
Lower resting heart rate.
Increased left ventricular volume.
Increased stroke vol. and cardiac output.
Capillarization: increase in capillary surface area in muscles.
Greater arteriovenous oxygen diff. (a-vO2)

30. D. Maximal Oxygen Consumption: (VO2) refers to the maximum amt
D. Maximal Oxygen Consumption: (VO2) refers to the maximum amt. of O2 that an individual can utilize during maximal training.
*measured as ml of O2 used in one minute per Kg of body weight.
(ml Kg-1 min-1)