Circulatory System Overview

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Questions and Answers

What is the main energy source for the myocardium?

Anaerobic respiration

Aerobic respiration (correct)

Glycolysis

Creatine phosphate

How does the oxidative capacity of myocardial tissue compare to skeletal muscle tissue?

Myocardial tissue has a three-fold higher oxidative capacity. (correct)

Myocardial tissue has a ten-fold higher oxidative capacity.

Myocardial tissue has a lower oxidative capacity.

Myocardial tissue has a similar oxidative capacity.

Why does myocardial tissue have a higher mitochondrial concentration than other tissues?

To increase the rate of protein synthesis.

To store more ATP for later use.

To facilitate the transport of oxygen to the cells.

To provide more energy for muscle contraction. (correct)

What is the primary function of the heart in the circulatory system?

To transport blood throughout the body. Signup and view all the answers

What is the approximate weight of an average male's heart?

11 oz Signup and view all the answers

How much blood does the heart pump per beat?

70 mL Signup and view all the answers

What percentage of total blood volume is found in the systemic circulation?

75% Signup and view all the answers

What percentage of total blood volume is contained within the heart at any given time?

7% Signup and view all the answers

What is the relationship between blood pressure and the resistance encountered in the circulatory system?

Blood pressure decreases proportionally to the resistance encountered. Signup and view all the answers

What is the primary factor influencing blood viscosity?

Blood flow velocity. Signup and view all the answers

How does the muscular wall of arteries compare to that of veins?

Arteries have thicker walls and are less distensible than veins. Signup and view all the answers

What is the main function of the muscular contractions and relaxations in the venous circuit?

To propel blood forward. Signup and view all the answers

How does the total area resistance of the circulatory system relate to blood pressure?

Blood pressure is inversely proportional to total area resistance. Signup and view all the answers

What is the effect of smaller muscular contractions in the venous circuit?

They cause a slight decrease in blood pressure. Signup and view all the answers

What is the relationship between the patterns of blood flow and the number of blood vessels?

The patterns of blood flow stay the same regardless of the number of blood vessels. Signup and view all the answers

What is the primary mechanism by which blood is propelled forward in the circulatory system?

Pressure gradients created by the heart. Signup and view all the answers

What is the primary function of the arterial system?

To propel oxygen-rich blood to the tissues Signup and view all the answers

How do arterial walls regulate peripheral blood flow?

By altering their internal diameter through smooth muscle contraction and relaxation Signup and view all the answers

What happens to blood flow during physical activity according to the arterial system's function?

Blood is diverted to active muscles from other areas Signup and view all the answers

What occurs when the radius of an artery is decreased by half?

Resistance increases by a factor of 16 Signup and view all the answers

What are arterioles primarily responsible for in the arterial system?

Distributing blood to capillary networks Signup and view all the answers

Which statement about blood flow and resistance in arteries is accurate?

Changes in diameter of arteries can significantly impact blood flow and pressure Signup and view all the answers

Why is gaseous exchange not facilitated in the arterial system?

The walls of arteries are impermeable Signup and view all the answers

What characterizes the arterial network's distribution of blood in the body?

It is intricate and provides efficient oxygen delivery Signup and view all the answers

What happens to blood pressure during high intensity exercise with little resistance?

Systolic blood pressure increases, while diastolic blood pressure decreases or remains unchanged. Signup and view all the answers

What is the effect on blood pressure when the exercise intensity is increased and the resistance is low?

Both systolic and diastolic blood pressure increase. Signup and view all the answers

What is the main reason for the temporary increase in systolic blood pressure during high intensity exercise?

Increased force of ventricular contraction. Signup and view all the answers

During high intensity exercise with low resistance, what happens to the arterioles?

They dilate, increasing blood flow. Signup and view all the answers

What is the expected effect on diastolic blood pressure during resistance training with body weight?

No change, or a slight decrease. Signup and view all the answers

What can be said about the duration of the elevated systolic blood pressure during high intensity exercise?

It is elevated for a short period of time, lasting only as long as the intensity is maintained. Signup and view all the answers

Which of the following is the most likely reason for the decrease in diastolic blood pressure during high intensity exercise with low resistance?

Increased arteriolar dilation. Signup and view all the answers

What is the most likely explanation for the temporary drop in diastolic blood pressure during high intensity exercise with low resistance?

The blood vessels are dilated to reduce resistance and allow for greater blood flow. Signup and view all the answers

Study Notes

Cardiovascular System in Exercise Physiology

The myocardium (heart muscle) relies primarily on aerobic reactions for energy at rest and during exercise.
Myocardial tissue has a higher oxidative capacity due to high mitochondrial concentration relative to skeletal muscle.
At rest, myocardial energy comes from glucose/glycogen, fatty acids, and lactate.
During moderate exercise, fatty acids and carbohydrates provide nearly equal energy substrates.
In prolonged submaximal endurance activities, almost 80% of the myocardial energy is derived from free fatty acid metabolism.
During intense exercise, lactate oxidation becomes a major energy source.

Cardiovascular System Structure and Function

The heart is 11 oz in males and 11oz in females, pumping around 70ml/2.4 oz per beat
The cardiovascular system consists of 4 main components: pump (heart), high-pressure distribution circuit (arteries), exchange vessels (capillaries), and a low-pressure collection and return circuit (veins).
Systemic circulation contains approximately 75% of the total blood volume in capillaries, small arteries, and small veins..
The heart contains only about 7% of the total blood volume.
Arteries have thick walls of elastic and muscle fibers, blood moves quickly and under high pressure.
Capillaries have very thin walls facilitating gas and nutrient exchange.
Veins have thinner walls and one-way valves that prevent blood from pooling.

Blood Flow and Pressure

Blood flows from the left side of the heart through arteries, capillaries, and veins, returning to the right side of the heart.
Blood flow velocity slows and total vascular area increases as blood moves from arteries to arterioles, capillaries, venules, and veins.
Blood pressure is highest in the aorta and progressively decreases as blood flows through the arteries, capillaries, and veins.
Systolic blood pressure is the pressure during ventricular contraction, and diastolic blood pressure is the pressure between contractions.
Maximal exercise increases systolic blood pressure significantly, whereas diastolic blood pressure changes are usually less and may even show a slight decrease.
This increase correlates to increased blood flow to working muscles due to vasodilation during heavy exercise.

Coronary Circulation

The coronary circulation supplies blood to the heart muscle.
Coronary arteries, shaded red, and coronary veins, shaded blue, are shown in the figure.
Obstruction of a coronary artery results in myocardial infarction.

Blood Vessel Structure and Function

Blood vessels have walls with varying thicknesses and compositions depending on their function (arteries high pressure, capillaries rapid exchange, and veins low pressure)
Blood vessels have smooth muscle layers that regulate blood flow rate depending on the body's needs and activities.
Valves in veins facilitate blood flow to the heart and prevent backflow.

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Description

Test your knowledge on the circulatory system with a focus on the heart and its functions. This quiz covers energy sources for myocardial tissue, blood circulation mechanics, and comparative anatomy between arteries and veins. Answer questions about blood volume, pressure dynamics, and the heart's role in the systemic circulation.