Book chapter
Normal Cardiac Function
Modern Surgical Care, pp 669-682
2006
Abstract
As a component of the cardiovascular system, the heart is
responsible for maintaining adequate blood flow to meet
the metabolic needs of the body. This is accomplished
by the integration of neural, metabolic, anatomic, and
physiologic subsystems that combine to form the intact,
functioning human heart. An understanding of cardiac function must consider each of these factors, because a knowledge of only one, or even several, without an appreciation
of the others gives an incomplete picture of the physiologic
mechanisms responsible for this function. In discussing cardiac physiology, it is appropriate to begin with the molecular
events underlying contraction and relaxation, to provide the
basis for understanding the performance of the intact organ.
The basis of cardiac function is the relationship between the
contractile proteins, actin and myosin. The nature of this
relationship determines to a large extent the characteristics
of activation and relaxation in individual muscle cells and
in the intact heart. As in skeletal muscle, the functional unit
of cardiac muscle is the sarcomere. The sarcomere is composed principally of four proteins (1). These are the previously mentioned contractile proteins, actin and myosin
and the regulatory complex consisting of tropomyosin and
troponin. In electron micrographs, the sarcomere appears
as an arrangement of thick and thin filaments. This arrangement is shown schematically in Figure 1. The thick filament
exists as an aggregate of myosin molecules. Myosin consists
of a pair of heavy, coiled polypeptide chains, each of which
is attached to a globular head region.
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Details
- Title
- Normal Cardiac Function
- Creators
- Andrew S Wechsler - [Retired Faculty]
- Contributors
- Thomas A Miller (Editor)
- Publication Details
- Modern Surgical Care, pp 669-682
- Publisher
- CRC Press
- Resource Type
- Book chapter
- Language
- English
- Academic Unit
- [Retired Faculty]
- Other Identifier
- 991019173875804721