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

Show the anatomical evidence, Q. Show the Anatomical Evidence? Anatomy ...

Q. Show the Anatomical Evidence? Anatomy is the study of the structure, organisation and development of cells and tissues of plants and animals. For over a century taxonomists

Which are growth tissues of plants, Which are growth tissues of plants? How...

Which are growth tissues of plants? How do they categorize and where can they be found? Growth tissues of the plants are the meristems. The Meristems are the tissues that produ

What are living and nonliving reservoirs, What are living and nonliving res...

What are living and nonliving reservoirs? Viruses are both living as well as non-living. They have reservoirs of genes. A one nucleotide is a unit of gene. Viral genes make use

Plantae, significance of amoebozoa

significance of amoebozoa

Functional regions of digestive system, Functional regions of digestive sys...

Functional regions of digestive system In general the digestive system of metazoans is divided into 4 major functional regions of: Reception Conduction and s

Development projects - deforestation, Development Projects - Deforestation ...

Development Projects - Deforestation The use of science and technology to support the ever- increasing needs of man is termed as development. In the recent years, the human po

What is the significance of malpighian tubules, What is the significance of...

What is the significance of Malpighian tubules? Excretory structures found in insects and some spiders. Though similar in appearance and function the two aren't homologous. Mal

Which compounds does not contain an amine, Which of the following compounds...

Which of the following compounds does NOT contain an amine? Select one: a. Glutamine b. Acetate ion c. Urea d. Guanidinium ion e. Creatine

Could this be accomplished by passive diffusion, In the human body, the pot...

In the human body, the potassium ion can pass easily through cell membranes, yet the potassium ion concentration is higher inside many cells than it is outside these cells. Could t

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