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 pulmonary edema, Q. What is Pulmonary Edema? When the capillary...

Q. What is Pulmonary Edema? When the capillary pressure exceeds the plasma osmotic pressure, fluid first accumulates in the interstitial spaces. The components of the interstit

Describe the factors of biological evolution of humans, Although there are ...

Although there are differences in interpretation of the evidence, it is generally accepted that human biological evolution has not been a linear progression from one species to the

How do the sodium and potassium ions maintain the neuron, How do the sodium...

How do the sodium and potassium ions maintain the resting potential of the neuron? The plasma membrane of the neuron when at rest maintains an electric potential difference amo

Tetrasporic embryo sacs, Tetrasporic Embryo Sacs In this group neithe...

Tetrasporic Embryo Sacs In this group neither of the meiotic divisions is accompanied by wall formation so that at the end of meiosis all the four haploid nuclei remain in a

Photosynthesis, explain the role of photophosphorylation and chemiosmosis i...

explain the role of photophosphorylation and chemiosmosis in photosynthesis

Instances of human diseases caused by bacteria, Q What are instances of hum...

Q What are instances of human diseases caused by bacteria? Some human diseases caused by bacteria are tuberculosis, pertussis, diphtheria, gonorrhea, bacterial meningitis, bubo

Explain indications for surgery in aortic aneurysm, Explain Indications for...

Explain Indications for Surgery in Aortic Aneurysm? Indications for Surgery :  Thoracic aortic aneurysms are classified by the portion of aorta involved - ascending, arch,

Explain phylogenetically proximal species, Q. Do the phylogenetically proxi...

Q. Do the phylogenetically proximal species have cells with proximal chromosome counts? The number of chromosomes typical of each species is proximal for phylogenetically proxi

Explain amantadine, Amantadine Treatment with oral amantadine or rimant...

Amantadine Treatment with oral amantadine or rimantadine begun within 48 hours after the onset of illness decreases the duration of fever and symptoms by about 1 day. Whether t

Pulse oximetry - diagnostic tests, Pulse Oximetry: Procedure: Pulse Ox...

Pulse Oximetry: Procedure: Pulse Oximetry is a safe and  simple method of assessing oxygenation. An  advantage is  that this method  is noninvasive and continuous. Previously,

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