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

Define adsorption chromatography -basic separation technique, Define Adsorp...

Define Adsorption chromatography - Basic Separation Technique? Adsorption is surface interaction and is by number of forces, between surface atoms of solids and molecules of ex

Animal Cells, what are the functions of cytoplasm ?

what are the functions of cytoplasm ?

What do you mean by ulcerative colitis, Q. What do you mean by Ulcerative C...

Q. What do you mean by Ulcerative Colitis? Let us understand clearly about ulcerative colitis by reading the following case. Varun, a 48-year-old male, had a very successful

Determine the various neurobehavioural characteristics, Determine the vario...

Determine the various neurobehavioural characteristics Contemporary views of brain function tend to conceptualise localisation in interaction with a number of developmental and

Zoology, living and non living

living and non living

What is the role of plant cells, What is the role of Plant Cells? Plant...

What is the role of Plant Cells? Plant cells function essentially in the same manner as other eukaryotic cells, but there are three unique structures which set them apart. Plas

Describe u - waves, Q. Describe U - Waves? The U-wave is usually uprigh...

Q. Describe U - Waves? The U-wave is usually upright if the T is also upright and is highest at low rates. When the heart rate increases to more than 90, the U-wave is rarely v

Define disadvantages of using yeast as a source of protein, Define Disadvan...

Define Disadvantages of using yeast as a source of protein? 1. Less protein yield (45-60%) 2. Growth rate is low (1-3 h) 3. High nucleic acid content leading to the forma

Define mid root perforation - types of root perforation, Define Mid root (l...

Define Mid root (latral) perforation? Perforation through latral wall of the root canal during cleaning and shaping or during post space preparation

What are the cell kinds that form the phloem, What are the cell kinds that ...

What are the cell kinds that form the phloem? What are the major features of those cells? The major cells that form the phloem are the sieve elements and the companion cells an

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