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Smooth muscle differs from skeletal muscle and cardiac muscle in terms of structure, function, regulation of contraction, and excitation-contraction coupling. However, smooth muscle tissue tends to demonstrate greater elasticity and function within a larger length-tension curve than striated muscle. This ability to stretch and still maintain ...
The smooth muscle of the blood vessels reacts to the stretching of the muscle by opening ion channels, which cause the muscle to depolarize, leading to muscle contraction. This significantly reduces the volume of blood able to pass through the lumen, which reduces blood flow through the blood vessel.
Depiction of smooth muscle contraction. Muscle contraction is the activation of tension-generating sites within muscle cells. [1] [2] In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding something heavy in the same position. [1]
Other effects on smooth muscle are contraction in: Ureter; Uterus (when pregnant): this is minor compared to the relaxing effects of the β 2 receptor, agonists of which—notably albuterol/salbutamol—were formerly [citation needed] used to inhibit premature labor. Urethral sphincter
Temporal motor unit recruitment, or rate coding, deals with the frequency of activation of muscle fiber contractions. Consecutive stimulation on the motor unit fibers from the alpha motor neuron causes the muscle to twitch more frequently until the twitches "fuse" temporally. This produces a greater force than singular contractions by ...
Generally, BER waves stimulate action potentials and action potentials stimulate contractions. The interstitial cells of Cajal are specialized pacemaker cells [3] located in the wall of the stomach, small intestine, and large intestine. [1] These cells are connected to the smooth muscle via gap junctions and the myenteric plexus.
Cardiac and smooth muscle contractions are stimulated by internal pacemaker cells which regularly contract, and propagate contractions to other muscle cells they are in contact with. All skeletal muscle and many smooth muscle contractions are facilitated by the neurotransmitter acetylcholine. [19]
Calmodulin plays an important role in excitation contraction (EC) coupling and the initiation of the cross-bridge cycling in smooth muscle, ultimately causing smooth muscle contraction. [34] In order to activate contraction of smooth muscle, the head of the myosin light chain must be phosphorylated.