Non-striated or smooth muscles, Biology

NONSTRIATED (= SMOOTH) MUSCLES -

  1. Non-striated muscles are found in the posterior part of oesophagus, stomach, intestine, lungs, urinogenital tract, urinary bladder, blood vessels, iris of eye, dermis of skin and arrector pili muscle of hair. Smooth muscles never connect with skeleton.
  2. These muscle fibres or cells are elongated and spindle shaped.
  3. Each fibre contains a single oval nucleus surrounded by the cytoplasm (sarcoplasm). In the cytoplasm the myo- fibrils are arranged longitudinally.
  4. There is no sarcolemma, however, the fibre is enclosed by plasma membrane.

1574_non striated muscles.png

 

FUNCTION -

These muscles help in peristalsis which happens in tubular viscera.

Action of these muscles is controlled by autonomic nervous system and hence they are not under the control of the animal's will.

 

TYPES -

Functionally smooth muscles are of two types : single-unit smooth muscles and multi-unit smooth muscles.

(i)       Single-unit smooth muscles are composed of muscle fibres closely joined together. All the fibres of the single smooth muscle contract together as a single unit. These muscles are found in the walls of hollow visceral organs like gastrointestinal tract and urinary bladder.

(ii)      Multi-unit smooth muscles are composed of independent muscle fibres and are not closely joined together. Their fibres contract as separate units. Arrector pili muscles of skin dermis, ciliary and iris muscles in the eyes, and muscles of the walls of the large blood vessels are some examples of multi-unit smooth muscles.

Posted Date: 10/1/2012 3:57:49 AM | Location : United States







Related Discussions:- Non-striated or smooth muscles, Assignment Help, Ask Question on Non-striated or smooth muscles, Get Answer, Expert's Help, Non-striated or smooth muscles Discussions

Write discussion on Non-striated or smooth muscles
Your posts are moderated
Related Questions
Which of the following best describes why Okazaki fragments are not observed in PCR? A. DNA primase is used for the entire reaction therefore eliminating the production of Okaz

Which kind of polarity do water-soluble and fat-soluble substances respectively have? Water-soluble substances are polar molecules, i.e., they have electrically charged areas.

Tantalum and Niobium in alloplastic implant materials  Tantalum has been used successfully in needle type, screw- type and double-bladed implants. However, both are difficult

The most recent blood work of a patient with a diagnosis of acute myelogenous leukemia (AML) reveals thrombocytopenia. Where is the patient most likely to experience abnormal bleed

who discovered it? and what is it''s physiologic functions?

Adsorption - Colloidal particle Colloidal particles attract and hold to their surfaces the molecules of various gases, vapors and other matter with which they come into contact

What do you understand by tegument? Outer covering of parasitic flatworms, including tapeworms and flukes, comprising a syncytial outer layer of cytoplasm connected to cell bod

Limitations of Five-Kingdom Classification As already pointed out, each system of classification has its own limitations. The two-kingdom system has outlived its usefulness as

Q. Dietary Recommendations in celiac disease? The only dietary treatment for celiac disease is to follow a gluten-free diet. For most such a diet improves symptoms, heals inte

What is the function of the collagen fibers of the connective tissue? There are dissimilar collagen types. The major function of these proteins is to keep the shape and the str