Non-striated or smooth muscles, Biology

Assignment Help:

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.


Related Discussions:- Non-striated or smooth muscles

How many different molecules composed, How many different molecules compose...

How many different molecules composed of (A) two (B) three, and (C) four amino acids, linked together by peptide bonds, can be made from the set of 20 naturally occurring amino aci

From molecules to the first cell, From Molecules to the First Cell The ...

From Molecules to the First Cell The prebiotic conditions on the earth in all probability were volcanic eruptions, lightning and heavy rains. There was no trace of free oxygen

Define procedure for testing presence of proteins in milk, Define Procedure...

Define Procedure for Testing the Presence of Proteins in Milk? 1. Add 0.5 ml of alcohol to 0.5 ml milk.  Alcohol helps in curdling the milk. 2. Observe for the curdling of m

Explain nature of fatty acids present in the triglyceride, Explain the Natu...

Explain the Nature of fatty acids present in the triglyceride? Nature of fatty acids present in the triglyceride determines the physico-chemical properties and biological signi

Explain the metabolic rate of aerobic organisms, Why can the consumption of...

Why can the consumption of molecular oxygen indicate the metabolic rate of aerobic organisms? Molecular oxygen (O2) consumption has direct relation to the cell metabolic rate i

What are the major features of the meristematic cells, What are the major f...

What are the major features of the meristematic cells? And why do these cells need to have a high mitotic rate? The Meristematic cells have very thin cell walls, a well-central

What are main limitations on size that can be synthesized, What are main li...

What are main limitations on size that can be synthesized and how will that be change over next few years? A: Today, a 10kb gene or longer is built as part of the regular produ

Explain about the secondary protein derivatives, Explain about the Secondar...

Explain about the Secondary Protein Derivatives? These are the products of further hydrolytic cleavage of the protein molecule, Examples include: a) Proteoses: Soluble in wa

Physical and chemical factors that affect the pasteurization, Define the Ph...

Define the Physical and Chemical Factors That Affect the Pasteurization? There are a few other physical and chemical factors that affect the pasteurization method. These involv

What is the estimated percentage of water in the human body, What is the es...

What is the estimated percentage (in mass) of water in the human body? Is this percentage expected to be larger in the adult or in the old individual? About 65% of the human in

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd