Tricuspid valve
Mitral valve
ANATOMY & PHYSIOLOGY
Ventricles relaxed
Ventricles contracted
The Heart Skeleton A semi-rigid, fibrous, connective tissue called the skeleton of the heart encircles each valve. Besides offering support for the heart, the skeleton keeps the valves from stretching; it also acts as an insulating barrier between the atria and the ventricles, preventing electrical impulses from reaching the ventricles other than through a normal conduction pathway. 298
Full-color Illustrations Meticulously detailed artwork and crystal-clear explanations make complex concepts and processes easy to understand.
Structures of the Heart
Key structures of the heart include the pericardium, the heart wall, the chambers, and the valves.
Pulmonary valve
The Pericardium Surrounding the heart is a double-walled sac called the pericardium . Anchored by ligaments and tissue to surrounding structures, the pericardium has two layers: the fibrous pericardium and serous pericardium.
The serous pericardium , which consists of two layers, covers the heart’s surface. The fibrous pericardium —a loose- fitting sac of strong connective tissue—is the outermost layer.
Aortic valve
Skeleton of heart, including fibrous rings around valves
Tricuspid valve
Mitral valve
At the heart’s base, the serous pericardium folds back on itself to form the:
The Body AT WORK Valves open and close in response to pressure changes within the heart. For example, when a ventricle relaxes, the pressure within that ventricle drops. The AV valve leaflets hang limply, allowing blood to flow through the open valve into the ventricle. As the ventricle fills, pressure in the ventricle rises. After filling, the ventricle begins to contract and the pressure rises even more. This increased pressure pushes against the cusps of the AV valve, causing it to snap closed. When pressure in the ventricle exceeds the pressure “downstream,” the semilunar valve pops open, allowing blood to flow out into the area of lower pressure.
• parietal layer, which lines the inside of the fibrous pericardium, and the • visceral layer, which covers the heart’s surface.
Between these two layers is the pericardial cavity. This cavity contains a small amount of serous fluid, which helps prevent friction as the heart beats.
Pericardium
Posterior view
The Heart Wall The heart wall consists of three layers: The endocardium lines the heart’s chambers, covers the valves, and continues into the vessels. It consists of a thin layer of squamous epithelial cells.
The myocardium, composed of cardiac muscle, forms the middle layer. It’s the thickest of the three layers and performs the work of the heart.
The epicardium, which consists of a thin layer of squamous epithelial cells, covers the heart’s surface. Also known as the visceral layer of the serous pericardium, the epicardium is closely integrated with the myocardium.
The Body at Work Brief summaries explain physiological processes.
FAST FACT The endocardium is very smooth, an important characteristic that helps keep blood from clotting as it fills the heart’s chambers.
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Essentials of Anatomy and Physiology, 8th Edition Valerie C. Scanlon, PhD
Tina Sanders, Medical Illustrator Fun to teach and easy to study
A student-friendly writing style, superb art program, and online activities instill confidence every step of the way. § Questions for every figure encourage critical thinking and reinforce understanding. § Clinical application boxes put theory into action. § A wealth of pedagogical features promotes learning. § Pretests and post-tests for every chapter with print and email capabilities assess progress.
Resources on FADavis.com
Student Workbook, 8th Edition Valerie C. Scanlon, PhD Tina Sanders, Medical Illustrator 432 pages | 225 illustrations Soft cover | 2019 $44.95 (US) ISBN-13: 978-0-8036-6938-3
624 pages | 381 illustrations Soft cover | 2019 $74.95 (US) ISBN-13: 978-0-8036-6937-6
Great textbook. “Excellent anatomy text. It explains things well and gives examples of applications and abnormalities.” —Online Reviewer
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