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However, cardiac muscle cells contain a diad, which is a linking of only one sarcoplasmic reticulum with its respective t-tubule. Another notable distinction between all muscle cells and cardiac muscle cells is the presence of intercalated discs. These tight connections between the cardiomyocytes allows for the accelerated sending of action ...
The muscularis mucosae (or lamina muscularis mucosae) is a thin layer of muscle of the gastrointestinal tract, located outside the lamina propria, and separating it from the submucosa. It is present in a continuous fashion from the esophagus to the upper rectum (the exact nomenclature of the rectum's muscle layers is still being debated).
T-tubules (transverse tubules) are extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells.With membranes that contain large concentrations of ion channels, transporters, and pumps, T-tubules permit rapid transmission of the action potential into the cell, and also play an important role in regulating cellular calcium concentration.
The unusual microscopic anatomy of a muscle cell gave rise to its terminology. The cytoplasm in a muscle cell is termed the sarcoplasm; the smooth endoplasmic reticulum of a muscle cell is termed the sarcoplasmic reticulum; and the cell membrane in a muscle cell is termed the sarcolemma. [9] The sarcolemma receives and conducts stimuli.
In mammals, triads are typically located at the A-I junction; [1] that is, the junction between the A and I bands of the sarcomere, which is the smallest unit of a muscle fiber. Triads form the anatomical basis of excitation-contraction coupling , whereby a stimulus excites the muscle and causes it to contract.
The sarcoplasmic reticulum is a network of the tubules that extend throughout muscle cells, wrapping around (but not in direct contact with) the myofibrils (contractile units of the cell). Cardiac and skeletal muscle cells contain structures called transverse tubules (T-tubules), which are extensions of the cell membrane that travel into the ...
In terms of tissue type, the body may be analyzed into water, fat, connective tissue, muscle, bone, etc. In terms of cell type, the body contains hundreds of different types of cells, but notably, the largest number of cells contained in a human body (though not the largest mass of cells) are not human cells, but bacteria residing in the normal ...
Smooth muscle is involuntary and found in parts of the body where it conveys action without conscious intent. The majority of this type of muscle tissue is found in the digestive and urinary systems where it acts by propelling forward food, chyme, and feces in the former and urine in the latter.