Chapter 9:
Circulatory Adaptations
to Exercise

EXERCISE PHYSIOLOGY

Introduction

•One major challenges to homeostasis posed by exercise is the increased muscular demand for oxygen,

•During heavy exercise, oxygen demands may ___________ by _____ to _____ times.

•Two major adjustments of blood flow are;

– cardiac output - Q factor (______________ x _______________)

–Redistribution of blood flow

•A thorough understanding of the cardiovascular system is essential to exercise physiology

The Cardiovascular System

Purposes of the CV System

1.Transport O₂ to_______________ and _______________

2.Transport of _______________ to tissues

3.Regulation of body __________________

The Circulatory System

•Heart

–_____________blood

•Arteries and arterioles

–Carry blood _______________ from the heart

•Capillaries

–____________________________________

•Veins and venules

–Carry blood ___________________ the heart

Structure of the Heart

_______________ and _______________ Circuits

Systemic circuit

•______________ side of the heart

•Pumps ___________________ blood to the whole body via ____________

•______________ deoxygenated blood to the right heart via _____________

Pulmonary circuit

•_______________ side of the heart

•Pumps __________________ blood to the lungs via _______________ arteries

•Returns oxygenated blood to the _______________ heart via pulmonary __________

The Myocardium

The Cardiac Cycle

Systole

•_____________ phase

Diastole

•_____________ phase

Pressure Changes During the Cardiac Cycle

Arterial Blood Pressure

•Expressed as systolic/diastolic

–Normal is ____________ mmHg

–High is ³_____________ mmHg

Systolic pressure (__________ number)

–Pressure generated during ________________ contraction (systole)

Diastolic pressure

–Pressure in the arteries during cardiac _______________ (diastole)

Blood Pressure

•Pulse pressure

–Difference between ____________ and ______________

•_________ arterial pressure (MAP)

–Average pressure in the arteries

Mean Arterial Pressure

Blood pressure of 120/80 mm Hg

MAP = 80 mm Hg + .33 (120-80)

= 80 mm Hg + 13

= 93 mm Hg

Measurement of Blood Pressure

Factors That Influence Arterial Blood Pressure

Electrical Activity of the Heart

•Contraction of the heart depends on ______________ stimulation of the ______________

•Impulse is initiated in the _______ ___________ and spreads throughout entire heart

•May be recorded on an ______________ (ECG)

Conduction System of the Heart

Electrocardiogram

•Records the electrical activity of the heart

•_____________-wave

–Atrial depolarization

•____________ complex

–Ventricular depolarization

•____________-wave

Ventricular repolarization

Electrocardiogram

Cardiac
Cycle
&
ECG

Diagnostic Use of the ECG

•ECG abnormalities may indicate _____________ _________ disease

–____________-segment depression can indicate myocardial ___________

Abnormal ECG

Cardiac Output

The amount of blood _______________ by the heart ___________ ___________

•Product of ______________ and ______________

–Heart rate = ______________ per minute

–Stroke volume = amount of blood ______________ in ______________ beat

Regulation of Heart Rate

Decrease in HR

–______________ nervous system

•Via ______________ nerve

–Slows HR by inhibiting __________ node

Increase in HR

–______________ nervous system

•Via cardiac ______________ nerves

–Increases HR by stimulating ________ node

Nervous System Regulation of Heart Rate

Regulation of ______________ ______________

End-diastolic volume (EDV)

–Volume of blood in the ______________ at the end of ______________ (“preload”)

Average aortic blood pressure

–Pressure the heart must pump ______________ to ______________ blood (“afterload”)

Strength of the ventricular contraction

–“______________”

End-Diastolic Volume

•Frank-Starling mechanism

–Greater preload results in stretch of ventricles and in a more forceful contraction

•Affected by:

______________

–______________

______________

The Skeletal Muscle Pump

•Rhythmic skeletal muscle contractions ______________ ______________ in the extremities toward the heart

•One-way valves in ______________ prevent backflow of blood

Average Aortic Pressure

Next Class Period

Demonstration of 3 – minute Step Test and

VO2 max Test (online)