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What are the two upper chambers of the heart called?
Atria
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What are the two lower chambers of the heart called?
Ventricles
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What are some of the important facts about the atria?
- - smaller than the ventricles
- - walls are thinner and less muscular
- - often called the receiving chambers
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What is the wall of each heart chamber composed of?
- myocardium
- . cardiac muscle tissue
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What is the septum between the atrial chambers called?
interatrial septum
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What is the septum between the ventricle chambers called?
interventricular septum
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Each chamber of the heart is lined by a thin layer of very smooth tissue called what?
endocardium
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- What is inflammation of the endocardium referred to as?
- What can happen if it becomes inflamed?
- - endocarditis
- - the endocardial lining becomes rough and abrasive to RBCs passing over its surface
- . blood flowing over a rough surface is subject to clotting, and a thrombus [clot] may form
- . rough spots caused by endocarditis often cause the release of platelet factors and results in a fatal blood clot
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The heart has a covering and a lining, what are they called?
- - pericardium has two layers:
- . the endocardium lines the heart chambers
- . the epicardium covers the surface of the heart
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What does the pericardium consist of?
- two layers of fibrous tissue with a small space in between
- . inner layer of the pericardium:visceral pericardium [or epicardium]
- . outer layer of the pericardium:parietal pericardium [or endocardium]
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The two pericardial layers slide against each other without friction when the heart beats because these are ____________.
- serous membranes with moist surfaces
- . a thin film of pericardial fluid furnishes the lubricating moistness between the heart and its enveloping pericardial sac
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What is the condition called whenever the pericardium becomes inflamed?
- pericarditis
- . causes the visceral and parietal pericardium to rub together - causing severe chest pain
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The heart serves as what?
a muscular pumping device for distributing blood to all parts of the body
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What is the contraction of the heart called?
systole
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What is the relaxation of the heart called?
diastole
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When the heart beats, the _____ contract first, forcing the blood into the _____. Once filled, the two _____ contract and force blood out of the heart.
- - atria
- - ventricles
- - ventricles
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During atria systole [contraction], cardiac muscle in the atrial wall contracts, forcing blood through the _____ _____ and into the ventricles.
atrioventricular valves
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During ventricular systole [contraction], the _____ _____ close, and blood is forced out of the ventricles through the _____ _____ and into the arteries.
- - atrioventricular valves
- - semilunar valves
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What are the two AV valves that separate the atrial chambers above from the ventricles below called? And where are they located?
- - bicuspid [or mitral] valve
- . located between the left atrium and ventricle
- - tricuspid valve
- . located between the right atrium and ventricle
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What do the AV valves do?
prevent back-flow of blood into the atria when the ventricles contract
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What attaches the AV valves to the wall of the heart?
chordae tendineae
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Where are the SL valves located?
between the two ventricular chambers and the large arteries that carry blood away from the heart when contraction occurs
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What are the two SL valves called? And where are they located?
- - pulmonary semilunar valve
- . located at the beginning of the pulmonary artery
- - aortic semilunar valve
- . located at the beginning of the aorta
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What do the two SL valves do?
- - the pulmonary semilunar valve allows blood going to the lungs to flow out of the right ventricle but prevents it from flowing back into the ventricle
- - the aortic semilunar valve allows blood to flow out of the left ventricle up into the aorta but prevents back-flow into this ventricle
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What are stenosed valves?
valves that are narrower than normal, slowing blood flow from a heart chamber
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Where is the heart located?
in the pericardial sac
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Where does the right side of the heart pump blood to?
it pumps the venous blood into the lungs
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Oxygenated blood returns from the _____ into the _____ _____ and is propelled by the left ventricle into the _____.
- - lungs
- - left atrium
- - aorta
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Where do the coronary arteries originate from?
- behind the cusps in the aorta
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Blood is supplied to the heart by what?
two coronary arteries
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Normally, the heart contracts rhythmically at a rate of __ to __ times per minute
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In diastole, the heart chambers dilate, which allows filling of the _____ _____ of the heart with _____ _____ blood while the _____ _____ of the heart is filled with _____ _____ _____ blood.
- - right side
- - peripheral venous
- - left side
- - oxygenated pulmonary venous
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During diastole, the ____ and _____ are dilated and the _____ _____ and _____ valves are closed to prevent regurgitation of blood. At the same time, the _____ and _____ valves are opened to allow inflow of blood into the dilated _____ from the _____.
- - ventricles
- - atria
- - semilunar
- - pulmonary
- - aortic
- - mitral
- - tricuspid
- - ventricles
- - atria
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All blood vessels are lined by what?
endothelial cells
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The arteries are of two types. The larger arteries, including the aorta, are classified as _____, whereas the smaller arteries are called _____.
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What prevents the back-flow of blood in veins?
valves hinder retrograde blood flow that could easily develop in this low pressure system
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