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

Explain what is mortality in coronaw artery disease, Explain what is Mortal...

Explain what is Mortality in coronaw artery disease ? Marked prematurity and extensive atherosclerosis leads to markedly higher mortality in young Asian Indians compared to oth

Explain glycolysis, Explain glycolysis? Name the two monosaccharides w...

Explain glycolysis? Name the two monosaccharides which readily enter the glycolytic pathway. Illustrate a diagrammatic sketch of the microscopic view of a mammalian sperm a

How to increased co2 levels in the atmosphere, Increased CO 2 levels in th...

Increased CO 2 levels in the atmosphere are correlated with rising global temperatures, leading many scientists to believe that the first phenomenon has caused the second. What wo

Define dietary and non dietary factors - causation of cancer, Define Dietar...

Define Dietary and Non Dietary Factors - Causation of Cancer? Several dietary and non-dietary factors (including genetics) can increase the risk in the causation of cancer. Som

Culturing, ime day 0 day 1 day 3 day 4 day 5 day 7 count ...

ime day 0 day 1 day 3 day 4 day 5 day 7 count blank 7 10 5 14 9 8 low 45&49 64&70 62&69 75&79 80&82 68&72

What is determined by tube feet, What is determined by tube feet? Hollo...

What is determined by tube feet? Hollow and fluid-filled tubes which are part of the water vascular system in Echinoderms. Muscles associated with tube feet allow them to be hy

Define the sources of vitamin e, Define the Sources of Vitamin E? Vitam...

Define the Sources of Vitamin E? Vitamin E is present in almost all foodstuffs. It is found in wheat germ, corn, nuts, seeds, olives, spinach, asparagus and other green leafy v

What is cell theory, What is cell theory? Cell theory declares that the...

What is cell theory? Cell theory declares that the cell is the constituent unit of living beings. Before the discovery of the cell, it was not identified that living beings

How do sponges try to protect themselves, Q. How do sponges try to protect ...

Q. How do sponges try to protect themselves against harm from the environment? Is that method rudimentary or efficient? Sponges can close their pores to avoid the entrance of w

Biology, what is the relationship between an infection and spleen

what is the relationship between an infection and spleen

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