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

Why do some trees lose their green color in the autumn, Why do some trees l...

Why do some trees lose their green color in the autumn? In autumn days become shorter and nights longer therefore there is a reduction of the photosynthesis rate and some plant

Regulation of heart, Regulation of Heart The number of electrical imp...

Regulation of Heart The number of electrical impulses initiated by the SA node is primarily the result of its innervation by fibers from both sympathetic and parasympath

What is class gastropoda in animal kingdom, What is Class Gastropoda in ani...

What is Class Gastropoda in animal kingdom? Snails and slugs are referred to as gastropods because of their characteristic body plan. "Gastro" is derived from the Greek word fo

Ornithine-urea cycle, Normal 0 false false false EN-IN ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What functions regulates by hypothalamus, Q. What functions regulates by hy...

Q. What functions regulates by hypothalamus? HYPOTHALAMUS - Main visceral control center of the body (yet small in size). Central to virtually all homeostatic control . Th

Nutrition, mode of nutrition in tapeworm

mode of nutrition in tapeworm

What food items include in clear liquid diet, What Food items include in cl...

What Food items include in clear liquid diet -  Clear, fat free soups/broths -  Light coffee, tea (without milk or cream) -  Strained fruit juices -  Tender coconut wa

Mitosis, explain mitosis in detail

explain mitosis in detail

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