Chapter 12 Flashcards
What causes the “Dub” sound of the heart beat?
The relaxation of the ventricles allows blood to flow backwards, closing the semi lunar valves.
What causes the “Lub” sound of the heart beat?
The contraction of the ventricle causes the atrio-ventricular valves to close.
What is an aneurysm?
Ballooning of a blood vessel.
What is the aorta?
It is the major systemic artery that receives blood from the left ventricle.
Describe the Aortic Semilunar Valve.
What is its function?
The semilunar valve between the left ventricle and the aorta that prevents blood from flowing from the aorta back into the heart.
What is an Arteriole.
A blood vessel that branches off from an artery.
What are Arteries?
The blood vessels that carry blood away from the heart.
Atherosclerosis -
blocking of the blood vessels
Plaque deposits interfere with blood flow
Platelets form a thrombus or embolus
What are the Atria?
The thin walled chambers that receive blood into the heart.
What are the Atrioventricular Valves?
The tissue located between the atria and the ventricles supported by chordae tendineae.
What is the Atrioventricular node?
(AV Node)
Def: Small region of neuromuscular tissue that transmits impulses received from the SA node to the ventricular walls.
The AV (atrioventricular) node is located in the base of the right atrium very near the septum (Fig. 12.6a). The SA node initiates the heartbeat and sends out an excitation impulse every 0.85 second. This causes the atria to contract. When impulses reach the AV node, a slight delay allows the atria to finish contraction before the ventricles begin to contract. The signal for the ventricles to contract travels from the AV node through specialized cardiac muscle fibers called the atrioventricular bundle (AV bundle) before reaching the numerous and smaller Purkinje fibers.
