Textbook Question
What effect does sympathetic stimulation have on the heart? What effect does parasympathetic stimulation have on the heart?
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Ch. 20 The Heart
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011
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Table of contents
- Ch. 1 An Introduction to Anatomy and Physiology25
- Ch. 2 The Chemical Level of Organization34
- Ch. 3 The Cellular Level of Organization29
- Ch. 4 The Tissue Level of Organization24
- Ch. 5 The Integumentary System17
- Ch. 6 Bones and Bone Structure33
- Ch. 7 The Axial Skeleton11
- Ch. 8 The Appendicular Skeleton17
- Ch. 9 Joints13
- Ch. 10 Muscle Tissue12
- Ch. 11 The Muscular System28
- Ch. 12 Nervous Tissue18
- Ch. 13 The Spinal Cord, Spinal Nerves, and Spinal Reflexes22
- Ch. 14 The Brain and Cranial Nerves20
- Ch. 15 Sensory Pathways and the Somatic Nervous System17
- Ch. 16 The Autonomic Nervous System and Higher-Order Functions30
- Ch. 17 The Special Senses15
- Ch. 18 The Endocrine System21
- Ch. 19 Blood31
- Ch. 20 The Heart31
- Ch. 21 Blood Vessels and Circulation26
- Ch. 22 The Lymphatic System and Immunity25
- Ch. 23 The Respiratory System4
- Ch. 24 The Digestive System18
- Ch. 26 The Urinary System31
- Ch. 27 Fluids & Electrolytes30
- Ch. 28 The Reproductive System12
- Ch. 29 Development and Inheritance17
Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011Not the one you use?Change textbook
Chapter 20, Problem 29
Harvey has a heart murmur in his left ventricle that produces a loud 'gurgling' sound at the beginning of systole. Which valve is probably faulty?
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Understand the phases of the cardiac cycle: systole is the phase when the ventricles contract to pump blood out of the heart.
Identify which valves are involved in the left ventricle during systole: the aortic valve opens to allow blood to flow into the aorta, and the mitral valve closes to prevent backflow into the left atrium.
Recognize that a murmur occurring at the beginning of systole suggests a problem with a valve that should be closing or opening at that time.
Since the murmur is described as a 'gurgling' sound in the left ventricle at the start of systole, consider that the mitral valve might be faulty, possibly leaking (mitral regurgitation) as it should be closed during ventricular contraction.
Conclude that the faulty valve is likely the mitral valve, as it is the valve between the left atrium and left ventricle responsible for preventing backflow during systole.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Heart Valves and Their Locations
The heart has four main valves: mitral and tricuspid (atrioventricular valves) and aortic and pulmonary (semilunar valves). The mitral valve is located between the left atrium and left ventricle, controlling blood flow into the left ventricle during diastole.
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3:55
Locations of Serous Membranes
Systole and Valve Function
Systole is the phase of the cardiac cycle when the ventricles contract to pump blood out. During systole, the atrioventricular valves (mitral and tricuspid) should be closed to prevent backflow, while the semilunar valves open to allow blood ejection.
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7:13Systole, Diastole, Pressure, & Valves
Heart Murmurs and Valve Dysfunction
Heart murmurs are abnormal sounds caused by turbulent blood flow, often due to valve defects. A loud 'gurgling' sound at the start of systole in the left ventricle suggests mitral valve regurgitation, where the valve leaks and allows blood to flow backward into the left atrium.
Recommended video:
Guided course
7:13Systole, Diastole, Pressure, & Valves
Related Practice
Textbook Question
The following measurements were made on two individuals (the values recorded remained stable for 1 hour):
Person 1: heart rate, 75 bpm; stroke volume, 60 mL
Person 2: heart rate, 90 bpm; stroke volume, 95 mL
Which person has the greater venous return?
Which person has the longer ventricular filling time?
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Textbook Question
Describe the effects of epinephrine, norepinephrine, glucagon, and thyroid hormones on the contractility of the heart.
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Textbook Question
Vern is suffering from cardiac arrhythmias and is brought into the emergency room of a hospital. In the emergency room he begins to exhibit tachycardia and as a result loses consciousness. Explain why Vern lost consciousness.
Textbook Question
Karen is taking the medication verapamil, a drug that blocks the calcium channels in cardiac muscle cells. What effect should this medication have on Karen's stroke volume?
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