What are the two upper chambers of the heart called?
What are the two lower chambers of the heart called?
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
What is the wall of each heart chamber composed of?
. cardiac muscle tissue
What is the septum between the atrial chambers called?
What is the septum between the ventricle chambers called?
Each chamber of the heart is lined by a thin layer of very smooth tissue called what?
- What is inflammation of the endocardium referred to as?
- What can happen if it becomes inflamed?
- 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
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
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]
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
What is the condition called whenever the pericardium becomes inflamed?
. causes the visceral and parietal pericardium to rub together - causing severe chest pain
The heart serves as what?
a muscular pumping device for distributing blood to all parts of the body
What is the contraction of the heart called?
What is the relaxation of the heart called?
When the heart beats, the _____ contract first, forcing the blood into the _____. Once filled, the two _____ contract and force blood out of the heart.
During atria systole [contraction], cardiac muscle in the atrial wall contracts, forcing blood through the _____ _____ and into the ventricles.
During ventricular systole [contraction], the _____ _____ close, and blood is forced out of the ventricles through the _____ _____ and into the arteries.
- atrioventricular valves
- semilunar valves
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
What do the AV valves do?
prevent back-flow of blood into the atria when the ventricles contract
What attaches the AV valves to the wall of the heart?
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
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
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
What are stenosed valves?
valves that are narrower than normal, slowing blood flow from a heart chamber
Where is the heart located?
in the pericardial sac
Where does the right side of the heart pump blood to?
it pumps the venous blood into the lungs
Oxygenated blood returns from the _____ into the _____ _____ and is propelled by the left ventricle into the _____.
- left atrium
Where do the coronary arteries originate from?
behind the cusps in the aorta
Blood is supplied to the heart by what?
two coronary arteries
Normally, the heart contracts rhythmically at a rate of __ to __ times per minute
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
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 _____.
All blood vessels are lined by what?
The arteries are of two types. The larger arteries, including the aorta, are classified as _____, whereas the smaller arteries are called _____.
What prevents the back-flow of blood in veins?
valves hinder retrograde blood flow that could easily develop in this low pressure system