Possible Answers: Superior vena cava and left ventricle. Correct answer: Right ventricle and pulmonary arteries. Explanation : When blood returns to the heart via the superior and inferior vena cavae, it is deoxygenated. All of the other answer choices contain at least one component that carries oxygenated blood. Possible Answers: Left ventricle, aorta, vena cavae, right atrium. Left ventricle, aorta, pulmonary veins, right atrium.
Right ventricle, pulmonary arteries, pulmonary veins, left atrium. Right ventricle, aorta, vena cava, left atrium. Correct answer: Left ventricle, aorta, vena cavae, right atrium.
Explanation : The heart is composed of two circuits: the pulmonary circulation on the right side of the heart, and the systemic circulation on the left side of the heart. Blood velocity is slowest through which of the following vessels? Possible Answers: Venules. Correct answer: Capillaries. Explanation : The velocity of blood is inversely proportional to the size of the vessel.
Which vessel carries blood away from the right ventricle of the heart? Possible Answers: Superior vena cava. Correct answer: Pulmonary arteries. Explanation : The pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs for oxygenation. Which of the following vessels is not involved in the systemic circulation?
Possible Answers: The vasa recta. Correct answer: Pulmonary veins. Explanation : The systemic circulation refers to the path that carries blood from the left ventricle, through the body, back to the right atrium. Possible Answers: Right ventricle.
Correct answer: Right ventricle. Explanation : When an obstruction causes a restriction of flow, increased pressure will occur upstream of the blockage.
Possible Answers: Aorta. Correct answer: Lung capillaries. Explanation : Oxygen partial pressure is likely to be highest in the lung capillaries, as this is where oxygen will be "loaded" on to hemoglobin molecules for transportation to the tissues. Possible Answers: Left ventricle. Explanation : Increased pulmonary resistance means that it will be more difficult to pump blood into the lungs.
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This notification is accurate. I acknowledge that there may be adverse legal consequences for making false or bad faith allegations of copyright infringement by using this process. Find the Best Tutors Do not fill in this field. Your Full Name. Phone Number. As the vessel diameter narrows, less blood and oxygen will pass through and a region of the myocardium will consequently not receive an adequate supply of oxygen.
This could result in angina and ultimately a myocardial infarction. Coronary circulation is the circulation of blood in the blood vessels of the heart muscle.
The vessels that deliver oxygen-rich blood to the myocardium are known as coronary arteries. The vessels that remove the deoxygenated blood from the heart muscle are known as cardiac veins. The blood supply to the heart is greater than that of other body tissues since the heart has a constant metabolic demand that must be satisfied to keep the heart pumping at all times.
Coronary Circulation : Coronary arteries labeled in red text and other landmarks in blue text. The coronary arteries originate from the left side of the heart descending from the aorta. There are multiple coronary arteries derived from the larger right and left coronary arteries.
For example, important coronary arteries that branch off from the larger arteries include the left anterior descending LAD coronary and the right posterior coronary. Coronary arteries run both along the surface of the heart and deep within the myocardium, which has the greatest metabolic demands of all the heart tissues due to its muscle content.
Epicardial coronary arteries, which run along on the surface of the heart, are capable of autoregulating vasodilation and vasoconstriction to maintain coronary blood flow at appropriate levels to fit the metabolic demands of the heart muscle.
These vessels are relatively narrow and thus vulnerable to blockage, which may cause a myocardial infarction. Subendocardial coronary arteries run deep within the myocardium to provide oxygen throughout the muscle tissue of the cardiac wall. In systole, the ventricular myocardium contracts, generating high intraventricular pressure and compressing the subendocardial coronary vessels while allowing the epicardial coronary vessels to remain fully open.
With the subendocardial coronary vessels compressed, blood flow essentially stops below the surface of the myocardium. In diastole, the ventricular myocardium contracts, lowering the intraventricular pressure and allowing the subendocardial vessels to become open again.
Due to the high pressures generated in the ventricular myocardium during systole, most myocardial tissue perfusion occurs during diastole. Additionally, catecholamines such as norephinephrine, which normally cause vasoconstriction will instead cause vasodilation within the coronary arteries. This mechanism is due to beta-adrenergic receptors in the coronary arteries and helps enable the increased cardiac output associated with fight-or-flight responses.
A myocardial infarction heart attack may be caused by prolonged ischemia oxygen deprivation in the heart, which occurs due to blockage of any of the coronary arteries. Since there is very little unnecessary blood supply to the myocardium, blockage of these vessels can cause serious damage.
When these vessels become blocked, the myocardium becomes oxygen-deprived, a condition called ischemia. Brief periods of ischemia in the heart are associated with intense chest pain called angina, which may either be transient if the clot breaks up on its own or stable if it does not. As the time period of ischemia increases, the hypoxic conditions cause muscle tissue to die, causing a myocardial infarction heart attack. Myocardial infarction is one of the most common causes of death worldwide.
The clots that cause the infarction are usually the result of ruptured atherosclerotic plaques that break off and occlude the coronary arteries, but arterial thrombosis from injury or pooled blood may also cause a heart attack. The tissues of the heart do not regenerate, so those that survive a myocardial infarction will generally have scar tissue in their myocardium and may be more susceptible to other heart problems in the future.
The atrioventricular valves separate the atria from the ventricles and prevent backflow from the ventricles into the atria during systole. A heart valve allows blood flow in only one direction through the heart, and the combination of the atrioventricular and semi-lunar heart valves determines the pathway of blood flow. Valves open or close based on pressure differences across the valve. The atrioventricular AV valves separate the atria from the ventricles on each side of the heart and prevent backflow of blood from the ventricles into the atria during systole.
Cross section of heart indicating heart valves : The four valves determine the pathway of blood flow indicated by arrows through the heart. The subvalvular apparatus describes the structures beneath the AV valves that prevent the valves prom prolapsing.
Valve prolapse means that the valves do not close properly, which may cause regurgitation or backflow of blood from the ventricle back into the atria, which is inefficient. The subvalvular apparatus includes the chordae tendineae and the papillary muscles.
The AV valves are anchored to the wall of the ventricle by chordae tendineae heartstrings , small tendons that prevent backflow by stopping the valve leaflets from inverting. The chordae tendineae are inelastic and attached at one end to the papillary muscles and at the other end to the valve cusps. Papillary muscles are finger-like projections from the wall of the ventricle that anchor the chordae tendineae.
This connection provides tension to hold the valves in place and prevent them from prolapsing into the atria when they close, preventing the risk of regurgitation. The subvalvular apparatus has no effect on the opening and closing of the valves, which is caused entirely by the pressure gradient of blood across the valve as blood flows from high pressure to low pressure areas.
The mitral valve is on the left side of the heart and allows the blood to flow from the left atrium into the left ventricle. It is also known as the bicuspid valve because it contains two leaflets cusps. The relaxation of the ventricular myocardium and the contraction of the atrial myocardium cause a pressure gradient that allows for rapid blood flow from the left atrium into the left ventricle across the mitral valve.
Atrial systole contraction increases the pressure in the atria, while ventricular diastole relaxation decreases the pressure in the ventricle, causing pressure-induced flow of blood across the valve. The mitral annulus, a ring around the mitral valve, changes in shape and size during the cardiac cycle to prevent backflow. The ring contracts at the end of atrial systole due to the contraction of the left atrium around it, which aids in bringing the leaflets together to provide firm closure during ventricular systole.
The tricuspid valve is the three-leaflet valve on the right side of the heart between the right atrium and the right ventricle and stops the backflow of blood between the two. The tricuspid valve functions similarly to the bicuspid valve except that three chordae tendineae connect the cusps of the valve to three papillary muscles, rather than the pair that connects the bicuspid valve.
Blood passes through the tricuspid valve the same as it does through the bicuspid valve, based on a pressure gradient from high pressure to low pressure during systole and diastole. For specific medical advice, diagnoses, and treatment, consult your doctor. Cook Children's. What Does the Heart Do?
What Does the Circulatory System Do? What Are the Parts of the Heart? The heart has four chambers — two on top and two on bottom: The two bottom chambers are the right ventricle and the left ventricle. These pump blood out of the heart. A wall called the interventricular septum is between the two ventricles. The two top chambers are the right atrium and the left atrium. They receive the blood entering the heart. A wall called the interatrial septum is between the atria.
The atria are separated from the ventricles by the atrioventricular valves: The tricuspid valve separates the right atrium from the right ventricle. The mitral valve separates the left atrium from the left ventricle. Two valves also separate the ventricles from the large blood vessels that carry blood leaving the heart: The pulmonic valve is between the right ventricle and the pulmonary artery, which carries blood to the lungs.
The aortic valve is between the left ventricle and the aorta, which carries blood to the body. What Are the Parts of the Circulatory System? Two pathways come from the heart: The pulmonary circulation is a short loop from the heart to the lungs and back again. The systemic circulation carries blood from the heart to all the other parts of the body and back again. In pulmonary circulation: The pulmonary artery is a big artery that comes from the heart. It splits into two main branches, and brings blood from the heart to the lungs.
At the lungs, the blood picks up oxygen and drops off carbon dioxide. The blood then returns to the heart through the pulmonary veins. In systemic circulation: Next, blood that returns to the heart has picked up lots of oxygen from the lungs. So it can now go out to the body.
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