The heart is composed of muscle cells (cardiomyocytes) that account for most of the heart mass and generate its pumping force. Other cell types (fibroblasts, vascular endothelial cells, vascular smooth muscle cells, immune cells) and the extracellular matrix also play key roles in cardiac function...
The Physiology of Cardiac MuscleA symposium in the May issue of the American Journal of Medicine covers the current state of our knowledge of the physiology of cardiac muscle in great detail. New techniques as well as new concepts have enabled scientists to study aspects of the problem undreamed...
The article presents information on cardiac muscle physiology. It describes the work cells and pacemaker cells of the cardiac myocyte. It discusses the distinction of the cardiac action potential from what can be seen in nerves. It relates the role of calcium in the excitation contraction coupling...
When the mechanical properties of isolated cardiac muscle are studied in the laboratory, we find that if the muscle is stimulated to contract at short resting sarcomere lengths (i.e., at low preloads) under isometric conditions (fixed length), the amount of active tension developed (total ...
Refractory Period: The refractory period of the heart is the duration of time during which a typical cardiac impulse cannot re-excite a section of cardiac muscle that has already been stimulated or excited. It is of two types: absolute refractory period and relative refractory period. Absolute Re...
CHAPTER 9 Cardiac Muscle; The Heart as a Pump and Function of the Heart Valves 心肌;心脏作为泵的作用 CHAPTER 10 Rhythmical Excitation of the Heart 心脏的节律性兴奋 CHAPTER 11 The Normal Electrocardiogram 正常的心电图 CHAPTER 12 Electrocardiographic Interpretation of Cardiac Muscle and Coronary Blood...
When a muscle fiber contracts, it also shortens so that external work can be performed. If we were to isolate a piece of cardiac muscle and study the effects of afterload on the velocity of fiber shortening, we would find that the greater the afterload, the slower the velocity of ...
Cardiac muscle physiology is similar to the physiology of skeletal muscle in several ways. Cardiac muscle contracts in response to elevated levels of calcium and is also striated; indicating that it also uses sarcomeres as its contractile unit. Like smooth muscle and unlike skeletal muscle, cardiac...
cardiac muscle cells. (b) A photomicrograph of cardiac muscle cells shows the nuclei and intercalated discs. (c) An intercalated disc connects cardiac muscle cells and consists of desmosomes and gap junctions. LM × 1600. (Micrograph provided by the Regents of the University of Michigan Medical...