NEWBIO - Lecture Exam 4 Study Guide Bio446L Human...

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Lecture Exam 4 Study Guide Bio446L Human Microscopic and Gross Anatomy Fall 2010 Cardiovascular System - Chapter 13, pages 364-395. 1. Trace the pathway of blood through the: 1) pulmonary circuit, 2) systemic circuit, and 3)coronary circulation. State the importance of each of these pathways. Pulmonary circuit: A. Blood enters through right atrium by the superior and inferior vena cava B. Blood is pumped through the tricuspid valve into right ventricle C. Blood is then taken into the pulmonary arteries after passing through the pulmonary semilunar valve D. Pulmonary arteries brings blood to the lungs where it release CO2 and picks up O2 during respiration E. Blood then leaves lungs through the pulmonary veins which enter the left atrium down to left ventricle through the bicuspid (mitral) valve. Blood then goes through the aortic, semilunar valve to the aorta and then to the body. F. Enters systemic circuit **Importance- bring deoxygenated blood to the lungs to be oxygenated and then sent through the systemic circuit Systemic circuit: The left ventricle contracts, forcing oxygenated blood through the aortic semilunar valve into the aorta. Immediately after exiting the heart, the aorta arches downward (descending aorta) to carry blood to the lower part of the body. Oxygenated blood makes it’s pathway from the aorta to smaller arteries, arterioles and then capillaries. This is where the exchange of O2 and CO2 takes place. O2 leaves the blood and diffuses into the cells and CO2 and wastes diffuse out of the cells and into the blood. The deoxygenated blood moves to venous capillaries, venules, veins and finally merge to form the superior and inferior vena cavae, which empty directly into the right atrium. **Importance- brings oxygenated blood to the rest of the body Coronary circulation is the circulation of blood in the blood vessels of the heart muscle (the myocardium ). The vessels that deliver
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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. Only source of blood supply to the myocardium = the coronary arteries 2 Types: Right coronary artery (with a posterior ventricular branch and marginal artery) and Left coronary arteries (both originate from the root of the aorta immediately above the aortic semilunar valve). The left branches into the left anterior descending artery (or anterior ventricular branch) and the circumflex artery. 2. In most blood vessels, blood flow peaks when the ventricles contract and force blood into the arteries. Explain why this is not the case in the coronary circulation. Contraction of the ventricles suppresses blood flow through the coronary arteries, because as the blood is pushed through the aortic semilunar valve, its flaps cover the openings into the coronary arteries from the aorta. *Remember that the coronary arteries originate from the base of the aorta, close to the semilunar valve, on the anterior
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This note was uploaded on 02/21/2012 for the course BIO 89515 taught by Professor Janmachart during the Fall '09 term at University of Texas.

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NEWBIO - Lecture Exam 4 Study Guide Bio446L Human...

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