Textbook Question
Describe how heart contraction and relaxation influence coronary blood flow
Name the major branches of the coronary arteries, and note the heart regions served by each
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Ch. 18 The Cardiovascular System: The Heart
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732
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Table of contents
- Ch. 1 The Human Body: An Orientation25
- Ch. 2 Chemistry Comes Alive24
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System12
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton14
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System25
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System25
- Ch. 13 The Peripheral Nervous System and Reflex Activity30
- Ch. 14 The Autonomic Nervous System16
- Ch. 15 The Special Senses26
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart25
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses27
- Ch. 22 The Respiratory System21
- Ch. 23 The Digestive System31
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System26
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System24
- Ch. 28 Pregnancy and Human Development25
- Ch. 29 Heredity11
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
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Hoehn, Haynes, Abbott 12th EditionCh. 18 The Cardiovascular System: The HeartProblem 21
Hoehn, Haynes, Abbott 12th EditionCh. 18 The Cardiovascular System: The HeartProblem 21Chapter 18, Problem 21
(a) Describe the common function of the foramen ovale and the ductus arteriosus in a fetus.
(b) What problems result if these shunts remain patent (open) after birth?
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(a) Begin by understanding the fetal circulation system, which includes special structures like the foramen ovale and the ductus arteriosus that allow blood to bypass the lungs, which are not yet functional before birth.
Explain that the foramen ovale is an opening between the right and left atria of the fetal heart, allowing blood to flow directly from the right atrium to the left atrium, bypassing the non-functioning fetal lungs.
Describe the ductus arteriosus as a vessel connecting the pulmonary artery to the aorta, which also helps divert blood away from the lungs by allowing it to flow directly into systemic circulation.
(b) Discuss the consequences if these shunts remain open (patent) after birth, when the lungs are supposed to take over oxygen exchange. This can cause abnormal blood flow patterns, leading to inefficient oxygenation and increased workload on the heart.
Specifically, explain that a patent foramen ovale or ductus arteriosus can cause mixing of oxygenated and deoxygenated blood, potentially resulting in symptoms such as cyanosis, heart murmur, or heart failure, depending on the severity.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Fetal Circulatory Shunts
The foramen ovale and ductus arteriosus are fetal shunts that direct blood flow to bypass the non-functioning fetal lungs. The foramen ovale allows blood to flow from the right atrium to the left atrium, while the ductus arteriosus connects the pulmonary artery to the aorta, ensuring oxygenated blood reaches systemic circulation.
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Closure of Fetal Shunts After Birth
After birth, the lungs expand and begin oxygen exchange, causing the foramen ovale and ductus arteriosus to close. This closure redirects blood flow through the lungs for oxygenation. Proper closure is essential for normal postnatal circulation and oxygen delivery.
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Consequences of Patent Foramen Ovale and Ductus Arteriosus
If the foramen ovale or ductus arteriosus remain open (patent) after birth, abnormal blood flow occurs, leading to mixing of oxygenated and deoxygenated blood. This can cause complications such as hypoxemia, heart strain, and increased risk of infections or heart failure, requiring medical intervention.
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Related Practice
Textbook Question
Discuss how the Frank-Starling law of the heart helps to explain the influence of venous return on stroke volume.
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Textbook Question
Name the elements of the intrinsic conduction system of the heart in order, beginning with the pacemaker
What is the important function of this conduction system?
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Textbook Question
You have been called upon to demonstrate the technique for listening to valve sounds.
Explain where you would position your stethoscope to auscultate.
(1) the aortic valve of a patient with severe aortic valve insufficiency and
(2) a stenotic mitral valve.
During which period(s) would you hear these abnormal valve sounds most clearly? (During atrial diastole, ventricular systole, ventricular diastole, or atrial systole?)
What cues would you use to differentiate between an insufficient and a stenotic valve?
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Textbook Question
Florita Santos, a middle-aged woman, is admitted to the coronary care unit with a diagnosis of left ventricular failure resulting from a myocardial infarction. Her history indicates that she awoke in the middle of the night with severe chest pain. Her skin is pale and cold, and moist sounds are heard over the lower regions of both lungs. Explain how failure of the left ventricle can cause these signs and symptoms.
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