TBL 3 Flashcards
Describe the pericardium
The pericardium is a serous membrane that protects the heart.
What are the two parts of the pericardium? Describe them
- The two main parts of the pericardium are the fibrous pericardium and the serous pericardium.envelope the heart and fixes its position in the mediastinum
- The fibrous pericardium prevents overstretching of the heart, provides protection and keeps it in place in the mediastinum.
- The serous pericardium is a thinner, more delicate membrane that forms a double layer around the heart;
what are the two parts to the serous pericardium?
There are two parts to the serous pericardium, which are the visceral and parietal pericardium. The visceral pericardium covers the surface of the heart and the parietal layer lines the chest wall. The pericardium cavity is formed between the two, which contains fluid that reduces friction between the membranes.
Describe pericarditis
Pericarditis is the inflammation of the pericardium. It occurs when the pericardial fluid diminishes and the parietal and the visceral layers rub together painfully.
Pericarditis can lead to a buildup of pericardial fluid or extensive bleeding into the pericardium.
Describe cardiac temponade
Cardiac tamponade is a compression of the heart caused by a buildup of the pericardial fluid. The pericardium cannot stretch and can stop the beating of the heart.
Describe the three layers of the heart wall.
The epicardium layer is also called the visceral layer of the serous pericardium, which is the thin, transparent outer layer of the wall. It is composed of materials that give the heart a smooth and slippery surface. The myocardium is the middle layer, made up of cardiac muscle tissue. This layer gives the heart its bulk and it pumping action.The endocardium is the innermost layer, it provides a smooth lining for the chambers of the heart and covers the valves of the heart. It’s continuous with the endothelial lining of the large blood vessels attached to the heart.
what are the 3 layers of the heart wall
Epicardium, myocardium, and the endocardium are the three layers of the heart wall.
Describe the four chambers of the heart
- Right atrium
Receives blood from the superior vena cava, inferior vena cava, and coronary sinus.
The posterior wall is smooth, while the anterior wall is rough due to muscular ridges called pectinate muscles.
A thin partition called interatrial septum is between the right and the left atrium.
Blood passes from the right atrium to the right ventricle through a valve called the tricuspid valve. - Right ventricle
Forms most of the anterior surface of the heart.
The inside contains ridges formed by raised bundles of cardiac muscle called trabeculae carneae.
It is separated from the left ventricle by a partition called the interventricular septum. - Left Atrium
Forms most of the base of the heart.
Receives blood from the lungs through four pulmonary veins.
Smooth posterior and anterior walls.
Blood passes from the left atrium to the left ventricle through the bicuspid (mitral) valve. - Left Ventricle
Forms the apex of the heart.
Also contains trabeculae carneae.
Blood passes from the left ventricle through the aortic valve into the largest artery of the body: the ascending aorta.
Describe the flow of blood through the heart beginning at blood entering from the venae cavae.
Deoxygenated blood enters the heart through the superior and inferior vena cava and the coronary sinus into the right atrium.
As the atrium contracts, blood flows from the right atrium to the right ventricle through the tricuspid valve, which closes when the ventricle is full to prevent blood from flowing backward to the right atrium while the ventricle contracts.
As the ventricle contracts, blood leaves the heart through the pulmonary valve into the pulmonary artery, where blood is oxygenated.
Oxygenated blood leaves the lungs through the pulmonary veins into the left atrium.
As the atrium contracts, blood flows from the left atrium to the left ventricle through the bicuspid valve, which closes when the ventricle is full to prevent blood from flowing backward to the left atrium while the ventricle contracts.
As the ventricle contracts, blood leaves the heart through the aortic valve to the aorta and systemic arteries of the body.
what are the 4 heart valves
-Atrioventricular valves: tricuspid (right) and bicuspid (left) valves
-Semilunar valves: aortic and pulmonary valves
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Between each atria and ventricle you have a set of valves called the atrioventricular valves. The tricuspid valve divides the right atrium and right ventricle while the bicuspid, or mitral, valve divides the left atrium and left ventricle. Between each ventricle and the vessel that it pumps blood into you have a set of semilunar valves. The pulmonary or pulmonic valve separates the right ventricle and pulmonary arteries while the aortic valve separates the left ventricle and aorta. The main function of the valves is to prevent backflow of blood in the heart.
describe the atrioventricular valves
-Atrioventricular valves: tricuspid (right) and bicuspid (left) valves
Separate the atria from the ventricles.
Allow flow from the atria to the ventricles but prevent flow in the opposite direction.
describe the semilunar valves
Semilunar valves: aortic and pulmonary valves
Are made up of three crescent moon-shaped cusps.
Allow ejection of blood from the heart into arteries but prevent backflow of blood into the ventricles.
Describe the muscles that support the atrioventricular (A-V) valves
Papillary muscles
Located in the ventricles of the heart.
Attached to the cusps of the atrioventricular valves via the chordae tendineae.
Contract to prevent valve cusps of being forced to open in the opposite direction into the atria due to high ventricular pressure.`
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The papillary muscles are the muscles that support the atrioventricular valves. They are found on the surface of the left and right ventricles and cause the tricuspid and bicuspid valve to shut upon contraction. These papillary muscles have small tendons called chordae tendineae that are attached to the valves which pull the valves shut when the papillary muscles contract.
Describe the role of the heart valves in producing the heart sounds.
Heartbeat is produced by the closing of the atrioventricular and semilunar valves.
First sound (S1; lubb; louder and longer) is caused by the turbulence associated with closure of the AV valves soon after systole begins.
Second sound (S2, dupp; shorter and not as loud) is caused by the turbulence associated with closure of the SL valves at the beginning of the of ventricular diastole.
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The classic sound description of when a heart contracts is termed “lub-dub” which is essentially the closing of the atrioventricular and semilunar valves. The “lub” coincides with the closing of both atrioventricular valves and the “dub” coincides with the closing of the semilunar valves.
Describe the coronary circulation: both arteries and veins.
Coronary circulation is the circulation in the blood vessels of the myocardium.
Coronary arteries supply oxygenated blood to the myocardium,
The myocardium has many anastomoses, which provide alternate routes for blood to reach a particular organ or tissue.
Coronary veins remove deoxygenated blood from the heart.
