Smooth muscles, Biology

Smooth Muscles

Smooth muscles do not have transverse striations like those of skeletal and cardiac muscles. The smooth muscles line the blood vessels, digestive tract, urinary bladder, uterus etc. These are also present in the iris and skin. Smooth muscles are small and spindle shaped. Each muscle has a single nucleus. The cytoplasm of the smooth muscle cells contains actin and myosin filaments arranged in a random manner. Despite the lack of internal organisation of the filaments, there is cross bridge formation between the actin and myosin filaments. The contraction mechanism in smooth muscles is similar to the sliding filament type of contraction as found in the skeletal muscles.

1860_Smooth Muscles.png

Figure: Smooth Muscles.

In order to contract, smooth muscle need not be stimulated through the nerves. They show spontaneous rhythmic contractions that can vary in both frequency and intensity. This spontaneous activity of smooth muscle, however, can be modified by nerves as well as by hormones such as epinephrine and norepinephrine. A distinctive feature of vertebrate smooth muscle is the slowness of response. Another important property of it is that the smooth muscle can maintain contraction for prolonged periods with very little energy expenditure.

Posted Date: 1/16/2013 4:47:49 AM | Location : United States







Related Discussions:- Smooth muscles, Assignment Help, Ask Question on Smooth muscles, Get Answer, Expert's Help, Smooth muscles Discussions

Write discussion on Smooth muscles
Your posts are moderated
Related Questions
Another important genus of mycotoxin producers is Fusarium, many species of which produce members of the trichothecene family of mold metabolites like deoxynivalenol, neosolaniol a

Moss Stage - Xerarch The accumulation of soil, particularly in the crevices and depressions of rock favours the growth of certain xerophytic mosses, e.g., species of Polytrich

Facilitation Model - Models of Succession This is considered as the classical model of succession. It is based on the assumption that species of a previous stage are replaced

Determine the categories of Latent squint Latent squint category there are five subtypes: 1)  Esophoria 2)  Exophoria 3)  Hypophoria 4)  Hyperphoria 5)  Cyclopho

Explain Temperate Deciduous Forests-Taiga and tundra? Temperate deciduous forests are typified by the type of forests predominantly found in the eastern and northeastern Unit

In what ways might (a) clothing, (b) housing, (c) writing, have contributed to the survival of human beings? a) Clothing and (b) housing provide warmth and shelter, and so hav

A cleavage furrow appears in the middle of the cell, deepens gradually and divides the cell into two. Thus, at the end of second meiotic division, four daughter cells are formed

Q What is osmotic pressure? Osmotic pressure is the pressure produced in an aqueous solution by a region of lower solute concentration upon a region of higher solute concentrat

Q. Precautions should be taken while exercising? Being a diabetic the patient has to take a few precautions. These are: - Initiate the exercise programme gently and then bui

Q. Pathophysiology of constrictive pericarditis? Ans. The thickened and rigid pericardium causes constriction of the heart and restricts ventricular dialatation and diasto