What Hormone Causes Contraction of Smooth Muscle

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  • Author: keith

Smooth muscles with one unit are located in the walls of hollow organs; Smooth muscles with several units are located in the airways of the lungs and large arteries. Smooth muscle cells in a single piece contract synchronously, are coupled by gap junctions and have a potential for spontaneous action. Smooth multiunit cells lack lacunar junctions and their contractions are not synchronized. Smooth muscles are stimulated by external stimuli, which leads to contraction. Each step is explained in more detail below. Smooth tissues containing muscles often need to be stretched, so elasticity is an important feature of smooth muscle. Smooth muscle cells can secrete a complex extracellular matrix containing collagen (mainly types I and III), elastin, glycoproteins and proteoglycans. Smooth muscle also has specific receptors for elastin and collagen to interact with these extracellular matrix proteins. These fibers with their extracellular matrices contribute to the viscoelasticity of these tissues. For example, large arteries are viscolelastic vessels that act as a cauldron of wind, propagating ventricular contraction and smoothing the pulsed flow, and smooth muscles in the middle of the tunic contribute to this property. Healthcare costs associated with asthma are estimated to have reached $81.9 billion in the United States in 2013. [16] With such a large health care burden, it is amazing to see that asthma results from something as simple as the contraction of smooth muscles.

Smooth muscles are an integral part of the human body; Its function is vital and present in almost all organ systems. In the cardiovascular system, the smooth muscles of the vessels are used to maintain blood pressure and flow; in the lungs, it opens and closes the airways; in the gastrointestinal system, it plays a role in motility and nutrient collection; And yet, it also serves a purpose in almost every other organ system. The wide distribution of smooth muscles throughout the body and its many unique properties make it essential for healthcare professionals to have a thorough understanding of their physiology, function and disease applications. As with all aspects of medicine, an ongoing amount of research is likely to change our future understanding of smooth muscle and its overall effects on disease. Current smooth muscle research has shown promise for future implications, such as .B restoration of endothelial tissue, which could reveal new ways to promote revascularization in the future. Even small changes in understanding like these could have an immeasurable impact on the treatment and mortality of cardiovascular disease in the future. [4] While smooth muscle physiology remains an exceptionally profound topic, a solid understanding of its impact on healthcare, even at the most basic level, will provide healthcare professionals with tools to achieve better healthcare outcomes now and in the future. Muscle contraction continues until ATP-dependent calcium pumps actively transport Ca++ ions in and out of the cell. However, a low concentration of calcium remains in the sarcoplasm to maintain muscle tone. This remaining calcium keeps the muscle slightly contracted, which is important in some pathways and around the blood vessels.

Smooth muscles (so called because cells have no streaks) are present in the walls of hollow organs such as the bladder, uterus, stomach, intestines and in the walls of passages, such as arteries and veins of the circulatory system, and the airways of the respiratory, urinary and reproductive systems ((figure)). Smooth muscles are also present in the eyes, where it works to change the size of the iris and change the shape of the lens; and in the skin, where it causes the hair to stand in response to cold or anxiety. In recent years, oxytocin has had a reputation as an “uncomplicated” hormone, with few clearly defined activities related to childbirth and breastfeeding. As with so many hormones, other research has shown many subtle but profound influences of this small peptide, especially in terms of effects on the brain. Oxytocin has been implicated in determining a range of social behaviors in species from mice to humans. For example, the secretion or administration of oxytocin in humans appears to enhance trust and collaboration within socially close groups while promoting defensive aggression against unrelated competing groups. diffuse on a sheet of muscle fibers, as shown in Figure 8-3. In most cases, these fibers do not come into direct contact with the membranes of smooth muscle fiber cells, but form so-called diffuse compounds, which secrete their transmitting substance in the matrix coating of smooth muscles, often a few nanometers to a few micrometers from muscle cells; The transmitting substance then diffuses to the cells. In addition, where there are many layers of muscle cells, nerve fibers innervate, often only the outer layer, and muscle excitation moves from this outer layer to the inner layers by derivation of the action potential in the muscle mass or by additional diffusion of the transmitting substance.

During contraction, a spatial reorganization of the contractile machines takes place in order to optimize the development of the force. [6] Part of this reorganization is that the vimentin in Ser56 is phosphorylated by a p21-activated kinase, resulting in some decomposition of the vimentin polymers. [6] Leiomyosarcomas are generally larger than the benign form and the boundaries are not well defined. Invasive growth, observed with malignant epithelial neoplasms, is not often observed, but large neoplasms penetrate into normal tissues and destroy them. The parallel arrangement of neoplastic cells in nested bundles is not as uniform as in leiomyoma and cells may have a less frequent fibrillary cytoplasm; Leiomyosarcomas therefore appear more cellular than leiomyomas (Figures 27.37 and 27.38). .