Cardiovascular System & Adaptations to Training

What are the three main components of the cardiovascular system?

Heart, blood, and blood vessels.

What is the main function of the cardiovascular system?

Transport oxygen, nutrients, waste products, and other substances.

How many chambers does the heart have?

Four chambers.

Approximately how much blood does the heart pump per beat at rest?

Approximately 70 mL.

Approximately how much blood does the heart pump per minute at rest?

Approximately 5 liters.

What are the atria?

Collection chambers that receive blood returning to the heart.

What are the ventricles?

Chambers that eject blood out of the heart.

What is the cardiac cycle?

The sequence of events during one heartbeat.

What is systole?

The phase when the ventricles contract and push blood out.

What is diastole?

The phase when the ventricles relax and fill with blood.

What happens to the aortic and pulmonary valves during diastole?

They close to prevent backflow.

What happens to the bicuspid and tricuspid valves during diastole?

They open to allow blood to flow into the ventricles.

What happens to the bicuspid and tricuspid valves during systole?

They close to prevent blood from flowing backward.

What is pulmonary circulation?

Deoxygenated blood travels from the right side of the heart to the lungs.

What does the right ventricle do?

Pumps deoxygenated blood to the lungs.

What does the left atrium receive?

Oxygenated blood returning from the lungs.

What does the left ventricle do?

Pumps oxygenated blood to the body's tissues.

What is hemoglobin?

An iron- and protein-based molecule in red blood cells that transports oxygen and carbon dioxide.

How many oxygen molecules can one hemoglobin bind?

Four oxygen molecules.

How does oxygen enter the blood in the lungs?

Oxygen diffuses through the alveoli membrane and binds to hemoglobin.

How does carbon dioxide leave the blood in the lungs?

Carbon dioxide diffuses into the alveoli.

What controls oxygen and carbon dioxide diffusion?

Partial pressure differences.

What is the myocardium?

The muscle fibers of the heart.

What is the myocardium's aerobic and anaerobic capacity?

Approximately 80% aerobic and 20% anaerobic.

What are intercalated disks and gap junctions?

Structures that allow ions and action potentials to pass between heart muscle cells.

What do desmosomes do?

Hold cardiac muscle cells together during contractions.

What fuels the myocardium at rest?

Fatty acids, glucose, and glycogen.

What becomes a main fuel source for the myocardium during exercise?

Lactate.

What is the SA node responsible for?

Initiating an action potential that causes the atria to contract.

What is the AV node responsible for?

Delaying the ventricular contraction.

What happens after the AV node?

The signal travels to the Purkinje fibers to stimulate ventricular contraction.

What does an EKG measure?

The electrical activity of the heart.

What is EDV (preload)?

The volume of blood in the ventricles at the end of diastole.

What is ESV (afterload)?

The volume of blood remaining in the ventricles after systole.

What is stroke volume (SV)?

The volume of blood ejected from a ventricle during systole.

What is the formula for stroke volume?

EDV - ESV = SV.

If EDV is 100 mL and ESV is 30 mL, what is SV?

70 mL.

What is ejection fraction (EF)?

The percentage of EDV ejected from the ventricle during systole.

What is the formula for ejection fraction?

SV / EDV x 100.

What is cardiac output (Q)?

The total volume of blood pumped by the heart per minute.

What is the formula for cardiac output?

Stroke Volume x Heart Rate = Cardiac Output.

What is normal resting cardiac output?

Approximately 5 L/min.

What can cardiac output reach during heavy exercise?

Approximately 20-25 L/min.

What is autoregulation?

Regulation of blood flow to prioritize areas of the body that need it.

What do arteries and arterioles do?

Carry oxygenated blood toward the body's tissues.

What do capillaries do?

Exchange oxygen, nutrients, and waste products with tissues.

What do venules and veins do?

Return deoxygenated blood toward the heart.

What is the main structural feature of large arteries?

More connective tissue and elastin for stretching and recoil.

What is the main structural feature of arterioles?

More smooth muscle, allowing vasoconstriction and vasodilation.

What are capillary walls made of?

A single layer of endothelial cells.

What do precapillary sphincters control?

Blood flow through capillaries.

What is coronary circulation?

Blood flow through the coronary arteries supplying the myocardium.

What do veins contain to help blood return to the heart?

Valves that help propel blood toward the heart.

What is the skeletal muscle pump?

Muscle contractions compress veins and help return blood to the heart.

What is blood pressure?

The force of blood against arterial walls during the cardiac cycle.

What happens to EDV with increased venous return?

EDV increases.

What is the Frank-Starling mechanism?

Increased venous return increases EDV and helps increase stroke volume.

What is myocardial hypertrophy?

Thickening and strengthening of the heart's ventricular walls.

What is arteriogenesis?

An increase in the size of existing arteries and arterioles.

What is angiogenesis?

The formation of new blood vessels.

How does aerobic training affect the ventricle cavity?

Increases ventricular cavity size.

How does aerobic training affect myocardial contractility?

Increases contractility and strengthens the heart.

How does aerobic training affect blood plasma volume?

Increases plasma volume, supporting preload and stroke volume.

How does aerobic training affect red blood cells and hemoglobin?

Increases their numbers and oxygen-carrying capacity.

How does aerobic training affect coronary arteries?

Increases their size and myocardial blood flow.

How does aerobic training affect endothelial function?

Improves vasodilation of arteries and arterioles.

How does aerobic training affect capillary density?

Increases the number of capillaries supplying the myocardium and muscle fibers.

What is the a-vO2 difference?

The difference in oxygen content between arterial and venous blood.

What happens to a-vO2 difference with aerobic training?

It increases, allowing greater oxygen extraction by tissues.

What is VO2max?

The maximum volume of oxygen the body can deliver and use during maximal aerobic exercise.

What are cardiovascular health benefits of aerobic training?

Improved BP, cholesterol, glucose control, reduced clotting and triglycerides.

How does aerobic training affect LDL and HDL?

Decreases LDL and increases HDL.

How does resistance training affect VO2max?

Typically little to no improvement compared with aerobic training.

What type of resistance training may improve VO2max?

Circuit resistance training and high-intensity functional training.