Chapter 10: The Cardiovascular System and Physical Activity

Question 1

Circulatory system serves five important functions during PA

Answer 1

1. Delivers oxygen to active tissues
2. aerates blood returned to lungs
3. transports heat
4. delivers fuel nutrients to active tissues
5. transports hormones

Question 2

Cardiovascular system is composed of four parts

Answer 2

1. Heart
2. Arteries
3. Capillaries
4. Veins

Question 3

Blood pressure during PA

Answer 3

SBP increases in the first few minutes, then levels off. DBP remains unchanged or decreases slightly. Resistance exercise increases blood pressure dramatically.

Question 4

myocardial oxygen utilization

Answer 4

at rest, myocardium extracts 70% to 80% of O2 in blood flowing through coronary vessels

Question 5

Three important mechanical factors determine myocardial oxygen uptake

Answer 5

1. Tension development within myocardium
2. myocardial contractibility
3. heart rate

We can calculate Rate Pressure Product (RPP) by SBP x HR

Question 6

Heart’s energy supply

Answer 6

myocardium relies exclusively on energy released from aerobic reactions. Glucose, fatty acids, and lactate formed from glycolysis in skeletal muscle provide the energy for myocardial functioning.

Question 7

Sympathetic and parasympathetic influence

Answer 7

Sympathetic: releases epinephrine and norepinephrine, results in tachycardia

Parasympathetic: releases acetylcholine, results in bradycardia

Question 8

Mechanoreceptors and chemoreceptors

Answer 8

Stimuli from these receptors monitor state of active muscle to create an appropriate CV response

Question 9

Blood Flow regulation

Answer 9

Flow = Pressure divided by resistance

Question 10

Three factors determine resistance to blood flow

Answer 10

Poiseuille’s Law

1. Viscosity (blood thickness)
2. Length of conducting tube
3. Radius of blood vessel

Question 11

Local blood flow regulation

Answer 11

Increases in temperature, CO2, acidity,
adenosine, nitric oxide, magnesium and potassium ions enhance regional blood flow.

Question 12

Neural blood flow regulation

Answer 12

Sympathetic and parasympathetic portions
of ANS override vasoregulation afforded by local factors to provide central vascular control.

Question 13

Hormonal blood flow regulation

Answer 13

Upon sympathetic activation, adrenal
glands release epinephrine and norepinephrine to cause general constrictor response except in heart and skeletal muscle blood vessels.

Question 14

Cardiac output

Answer 14

heart rate x stroke volume

Question 15

Fick Principle

Answer 15

Relationship among cardiac output, VO2, and differences between O2 content of arterial and mixed- venous blood (a-VO2diff)

Question 16

Three physiological mechanisms increase heart’s stroke volume in PA

Answer 16

1. Enhanced cardiac filling
2. Neurohormonal influence
3. Training adaptations