ACE's Essentials of Exercise Chapter 5

Front

What does the sinoatrial (SA) node do?

Back

Regulates heart rate

Front

What does the atrioventricular (AV) node do?

Back

Its many branches facilitate ventricular contraction.

Front

Transmit parasympathetic input to the heart. Release acetylcholine when stimulated which causes a decrease in the activity of SA and AV nodes. At rest, the heart is primarily under the influence of vagus nerves.

Back

Vagus nerves

Front

What does an increase in sympathetic activity do?

Back

It increases heart rate.

Front

Sympathetic fibers reach the heart through what?

Back

Cardiac Accelerator Nerves, which innervate the SA node and the ventricles

Front

What does the stimulation of Cardiac Accelerator Nerves release?

Back

Catecholamines called epinephrine and norepinephrine. They cause the heart to beat faster (chronotropic response) and increase the force of heart contractility (inotropic response).

Front

Frank-Starling Mechanism of the heart does the following: Intrinsic ability of the heart to adapt to increasing volumes of in flowing blood. Cardiac tissue is stretched creating an increase in ventricular force to pump out blood.

Back

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Front

Vasoconstriction

Back

narrowing of blood vessels

Front

Vasodilation

Back

A widening of the diameter of a blood vessel.

Front

Autoregulation

Back

automatic regulation or reflex control of blood flow in an area depending on the local needs