Download Chapter 15

Chapter 15
The Cardiovascular System
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Cardiovascular System
Components
•
•
•
•
Heart: Pump
Arteries, Arterioles: Distribution system
Capillaries: Exchange vessels
Veins: Collection and return system
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
The Heart
• Myocardium
– Striated lattice-like network
– Functions as a unit
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Functions of the Heart
• Functions of right side
– Receive blood returning from body
– Pump blood to lungs for gas exchange
• Functions of left side
– Receive oxygenated blood from lungs
– Pump blood into systemic circulation
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
The Arterial System
• AortaArteriesArterioles
• Vessels have endothelial tissue, smooth
muscle, and connective tissue.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Blood Pressure
• Pressure generated by the pumping action
of the heart and the resistance of the
blood vessels
• BP = Cardiac output × Total peripheral
resistance
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Blood Pressure
• Systole
– Contraction phase
• Diastole
– Relaxation phase
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Blood Pressure Measurement
• Auscultation method
– Listen for Korotkoff sounds.
– Use a stethoscope and sphygmomanometer.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Mean Arterial Pressure
• MAP = Diastolic BP + [0.333 (Systolic −
Diastolic)]
• Reveals information regarding workload of
the heart
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Capillaries
Microscopic vessels 7 – 10 m in diameter
Contain 6% of total blood volume
Walls contain one layer of epithelial cells
Skeletal muscles have a dense capillary
network.
• Myocardium has an even denser network.
•
•
•
•
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Blood Flow in Capillaries
• Precapillary sphincters regulate flow.
• Capillaries open and flow increases
during exercise.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Venous Return
• One-way valves prevent back flow.
• Veins serve a capacitance role.
– At rest, ~ 65% of blood is on the venous side
of the system.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Varicose Veins
• When one-way valves become defective,
blood pools.
• Usually occurs in surface veins
– Less musculature to help compress vessels
– Occurs most frequently in legs
• Phlebitis
– Severe varicose veins with inflammation
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Venous Pooling
• Muscle pump
– Prevents pooling and edema
– Directs blood back towards the heart
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Hypertension
• Chronically elevated blood pressure
> 140 / 90 mm Hg
• Imposes a strain on the CV system
• It is a prevalent disorder.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Effective Treatment
•
•
•
•
•
•
Medications
Regular physical activity
Weight loss
Stress management
Decreased sodium intake
Decreased alcohol consumption
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
BP Response to Exercise
• Resistance exercise
– Straining compresses vessels.
– Peripheral resistance increases.
– Blood pressure increases in an attempt to
perfuse tissues.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Steady-Rate Exercise
• Systolic pressure increases with increases
in workload.
– There is a linear relationship between
workload and systolic BP.
• Diastolic pressure remains fairly constant.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
BP Response to
Upper-Body Exercise
• Resistance to flow is increased with
upper-body exercise.
• Smaller vessels in upper body compress
more easily.
• Care is required for individuals with heart
and valve diseases.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
BP in Recovery
• Following endurance exercise, there is a
hypotensive response.
• BP temporarily falls below normal resting
values.
• Regular exercise may help control moderate
hypertension.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
The Heart’s Blood Supply
• Coronary circulation
– Right and left coronary arteries branch off the
upper ascending aorta.
– RCA supplies predominantly the right atrium
and ventricle.
– LCA supplies the left atrium and ventricle and a
small portion of the right ventricle.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Myocardial O2 Use
• At rest, myocardium extracts ~ 70 – 80%
available O2.
• During exercise, flow must increase to meet
O2 demand.
– Flow may increase 4 – 6 times.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Effects of Impaired Blood Supply
• Impaired flow usually results in angina
pectoris.
• If flow is severely reduced, myocardial
infarction may result.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Rate-Pressure Product:
An Estimate of Myocardial Work
• Rate-Pressure Product or Double Product
RPP = SBP × HR
• Is a commonly used measure of
myocardial work
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Myocardial Metabolism
• Myocardium has a significantly higher
mitochondrial density compared with
skeletal muscle.
• This allows the heart to utilize
– Glucose
– Fatty acids
– Lactate
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Myocardial Metabolism
• Endurance exercise training increases the
ability to use lactate and fatty acids for
fuel.
• Decrease reliance on CHO
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition