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

What is invertebrates, What is Invertebrates? Invertebrates: About 99...

What is Invertebrates? Invertebrates: About 99% of all the animals lack backbones, and are invertebrates! Invertebrates include the phylum Arthropoda, or the animals with joi

Dormant vegetative structures, Dormant Vegetative Structures You have ...

Dormant Vegetative Structures You have learnt that light a period of chilling or application of gibberellin often breaks seed dormancy and stimulates seed germination. Vegetat

Glycolipids, G L YCOLIPIDS They are lipids having sugar residues. ...

G L YCOLIPIDS They are lipids having sugar residues. Two common glycolipids are cerebrosides and gangliosides. (1) Cerebrosides They are made of amino alcohol sphi

INVERTIBREATHE, #question.WRITE THE CHARACTER AND CLASSIFICATION OF MOLLUSC...

#question.WRITE THE CHARACTER AND CLASSIFICATION OF MOLLUSCA ?

Morula in humans, Which one of the following statements about morula in hum...

Which one of the following statements about morula in humans is correct? 1. It has almost equal quantity of cytoplasm as an uncleaved zygote but much more DNA 2. It has far l

Synovial fluid and amniotic fluid collection, Synovial fluid Collection: ...

Synovial fluid Collection: The technique of obtaining synovial fluid is called arthrocentesis. It is used to characterize type of arthritis and to differentiate inflammatory

Explain about the colorimeter, Explain about the Colorimeter? Colorimet...

Explain about the Colorimeter? Colorimeter is an instrument for measuring the colour or colour intensity of a solution. It is an instrument that measures the concentration of a

Define the control of tear production, Define the control of tear productio...

Define the control of tear production. Control of Tear Production The lacrimal secretary system was initially thought to be comprised of two parts, basic secretors and r

Find the genotypes and phenotypes of the f1, Determine the genotypes and ph...

Determine the genotypes and phenotypes of the F1 generation from a colour blind father and a mother who is homozygous for normal colour vision.

Mollusca, what is phylum mollusca?

what is phylum mollusca?

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