The Heart, Ch17 Flashcards
Both the right and left atria receive blood from what, which are blood vessels that bring blood to the heart? Blood drains from the atria to the ventricles, which pump blood into vessels called what, which carry blood away from the heart?
Veins. Arteries.
The right side of the heart is called what, because it pumps blood into a series of blood vessels leading to and within the lungs? What kind of blood does it deliver? This is collectively called what?
Pulmonary pump. It delivers oxygen-poor and carbon dioxide-rich/deoxygenated blood to the lungs. Pulmonary circuit.
Explain the heart’s physical position in the body?
It is situated slightly to the left side in the thoracic cavity, posterior to the sternum in the mediastinum, where it rests on the diaphragm. Its apex points toward the left hip, and its flattened base is its posterior side facing the posterior rib cage. Weighs 250-350 grams.
How does gas exchange occur between alveoli in the lungs and the pulmonary capillaries?
Oxygen diffuses from the air in the alveoli into the blood in the pulmonary capillaries, and carbon dioxide diffuses from the blood in the pulmonary capillaries to the air in the alveoli, to be expired. The veins of the pulmonary circuit then deliver the oxygenated blood to the left side of the heart.
The left side of the heart is often called called what? What sort of blood does it receive from the pulmonary veins? What circuit is it involved in?
Systemic pump. It receives oxygenated blood from the pulmonary veins and pumps it into blood vessels that serve the rest of the body, collectively called the systemic circuit.
In the systemic circuit, how does gas exchange occur?
Arteries deliver oxygenated blood to the smallest blood vessels, the systemic capillaries. Oxygen diffuses from blood into the tissues, and carbon dioxide diffuses from tissues into the blood. The blood is then deoxygenated and the veins of the systemic circuit then deliver it to the right side of the heart, to be pumped into the pulmonary circuit.
How does ANP from the heart lower blood pressure?
Atrial natriuretic peptide decreases sodium ion retention in the kidneys, therefore reducing osmotic water reabsorption and the volume and pressure of blood in the blood vessels.
What is the membranous structure that surrounds the heart? What are the two components of this sac?
Pericardium. Fibrous pericardium. Serous pericardium.
What is the tough outer layer of the pericardium that attaches the heart to surrounding structures? Describe.
Fibrous pericardium. Composed of two collagen bundles that enable it to anchor the heart to structures such as the diaphragm and great vessels. Collagen also gives it great distensibility, in that it doesn’t change size or shape considerably when stretching forces are applied. This helps prevent the heart chambers from overfilling with blood.
What are the two layers of the serous pericardium?
The outer layer is the parietal pericardium, which is fused to the inner surface of the fibrous. When it reaches the great vessels, it folds under itself and forms another layer that adheres directly to the heart. This is the visceral pericardium, or epicardium.
What is the second and thickest layer of the heart wall, deep to the superficial areolar connective tissue? What is it composed of?
Myocardium, composed of cardiac muscle tissue and a fibrous skeleton. Muscle tissue is made of myocytes, and their surrounding extracellular matrix. They are attached to and woven through the fibrous skeleton, which is composed of dense irregular collagenous connective tissue.
The lumen of the heart is composed of the third and deepest layer of the heart wall, which is what? What is it composed of?
The endocardium. Composed of simple squamous epithelium called endothelium, as well as several layers of connective tissue with elastic and collagen fibers.
What delivers blood to the coronary capillary beds, where gas and nutrient exchange takes place within the myocardium? Then the deoxygenated b,old drains from capillaries into a set of what?
Coronary arteries. Coronary veins.
The main systemic artery into which the left ventricle pumps blood is what? Immediately after it emerges from the left ventricle, what two branches arise?
Ascending aorta. The right and left coronary arteries.
The right coronary artery travels inferiority and laterally along the right atrioventricular sulcus, where it gives off what branches that supply the right atrium and ventricle?
Marginal artery, which is the largest branch. Posterior interventricular artery, which travels in the posterior interventricular sulcus.
What two vessels does the left coronary artery branch into?
Anterior interventricular artery, or left anterior descending artery (LAD), which travels along the anterior interventricular sulcus. Circumflex artery, curves along the left antrioventricular sulcus.
Systems of channels formed between blood vessels. The coronary arteries or veins may form these with one another, with branches from the pericardium, or with arteries or veins that are outside of the coronary circulation.
Anastomoses. When blood flow to the myocardium is lacking, occasionally new ones will form to provide alternate routes of blood flow, or collateral circulation, to the myocardium.
Generally the majority of the heart’s veins empty into a large venous structure on the heart, called what, which drains into the posterior right atrium. It receives blood from what three major veins?
Coronary sinus. Great, small, and middle cardiac vein.
A buildup of fatty material called plaques may result in this, which is the leading cause of death worldwide? It decreases blood flow to the myocardium, which results in inadequate oxygenation, a condition known as what?
Coronary artery disease, CAD. Myocardial ischemia.
This occurs when plaques in the coronary arteries rupture and a clot forms that obstructs blood flow to the myocardium. The causes the myocardial tissue supplied by that tissue to die. What happens to cells after death?
Myocardial infarction, or heart attack. Infarct, as in die. Because myocytes generally do not undergo mitosis, the dead cells are replaced with fibrous, noncontractile scar tissue, which increases the workload of the remaining heart muscle.
What is involved in a coronary angioplasty, a treatment for CAD?
A balloon is inflated in the blocked artery and a piece of wire-mesh tubing called a stent may be inserted into the artery to keep it open.
What occurs during coronary artery bypass grafting, a treatment for CAD?
Other vessels are grafted onto the diseased coronary artery to bypass the blockage and provide an alternate route for blood to flow.
These vessels bring blood to and away from the heart, and awe the largest ones in the body. Name the four.
Major systemic veins, the superior and inferior vena cava. Pulmonary trunk. Pulmonary veins. Aorta.
These two veins drain the majority of the systemic circuit. Which drains deoxygenated blood from veins superior to the diaphragm? Which drains from veins that are inferior?
Major systemic veins, the superior and inferior vena cava. The superior drains blood from veins superior, while the inferior drains from the inferior.
This large vessel receives deoxygenated blood pumped from the right ventricle. After a short distance it splits into two arteries, which bring deoxygenated blood to the right and left lungs.
Pulmonary trunk, which splits into the right and left pulmonary arteries. The arteries branch extensively inside the lungs to become pulmonary capillaries where gases are exchanged.
Once the blood is oxygenated in the pulmonary capillaries, it returns to the heart via a set of? Most people have two from each lung, that drain oxygenated blood into the posterior part of the left atrium.
Pulmonary veins.
This supplies the entire systemic circuit with oxygenated blood. It is the largest and thickest artery in the circuit, and the entire body.
Aorta. Stems from the left ventricle as the ascending aorta; after which it turns left and becomes the aortic arch.
Which atrium is larger, thinner-walled, and more anterior than other? Which is thicker-walled, somewhat smaller, and located mostly on the posterior?
Right atrium. Left atrium.
What thin wall separates the two atria? What indentation is in it? It’s the remnant of what hole, which used to do what?
Interatrial septum. Fossa ovalis. Foramen ovale used to direct blood from the right atrium directly to the left, bypassing the pulmonary circus kroon because fetal lungs are not yet functional.
This ventricle is wider and has thinner walls. It is shorter and crescent-shaped in cross-section. The other ventricle has greater muscle mass, three times thicker than the first. It is longer and circular in cross-section.
Right ventricle is thinner and moony. Left is thick and circular.
Internally both ventricles have a ridged surface created by irregular protrusions of cardiac muscle tissue referred to as what?
Trabeculae carneae. “Beams of flesh.”
What finger-like projections of muscle are in the ventricles? These contract just before the ventricles begin ejecting blood, creating tension on what to keep the valves closed?
Papillary muscles. Chordae tendineae.
What thick muscular wall separates the right and left ventricles? It also connects with the rest of the ventricular muscle and helps to expel blood into the pulmonary trunk and aorta.
Interventricular septum.
Backward flow of blood is prevented by these between the atria and the ventricles, composed of endocardium overlying a core of collagenous connective tissue. Which is between which?
Atrioventricular valves (AV). The tricuspid valve is between the right atrium and ventricle. The bicuspid/mitral valves is on the left.
What prevents the backflow of blood into the ventricles from the pulmonary artery and the aorta? Which is which?
Semilunar valves (SL). The pulmonary valve is between the right ventricle and pulmonary trunk. The aortic valve is between the left ventricle and the aorta.
What are the two types of valvular defects? Which valves are most commonly affected? What’s a sign?
An insufficient valve fails to close fully. A stenotic valve is when calcium deposits build up on the cusps, making them hard and inflexible. The heart has a harder time because of this. Mitral and aortic valves are most commonly affected. Can cause heart murmurs.
These cardiac muscle cells rhythmically and spontaneously generate action potentials that trigger the other type of cardiac muscle cell to also have action potentials. What property does this give cardiac muscle?
Pacemaker cells. Contractile cells. Autorhythmicity.
