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

Economic significance - conservation of wildlife, Economic Significance - C...

Economic Significance - Conservation of Wildlife Certain wild species are important because of their actual or potential economic value to people. Wildlife resources provide p

Define neurological disorders of non- nutritional etiology, Define Neurolog...

Define Neurological disorders of non- nutritional etiology? Some of the common disorders are Alzheimer's disease, Parkinson's disease, epilepsy, and spinal and neuro trauma.

Reproduction on land, Describe the evolution of egg structures and embryolo...

Describe the evolution of egg structures and embryological development for animals that have become adapted to terrestrial existence.

Explain working of cerebral cortex, Q. Explain working of Cerebral Cortex? ...

Q. Explain working of Cerebral Cortex? Cerebral Cortex/Cerebrum: The cerebrum or the cortex is the large part of the brain and is associated with the cognitive functions of the

Define the term epimerism, Define the Term Epimerism? In addition to D ...

Define the Term Epimerism? In addition to D and L isomerism sugars also exhibit epimerism. Hexoses that differ from each other as a result of variation of H and OH on carbons 2

Starch, why is it necessary to grind the food samples before testing?

why is it necessary to grind the food samples before testing?

Explain the scanning electron microscope, Explain the Scanning Electron Mic...

Explain the Scanning Electron Microscope It can be used to observe intact cells or cell components directly. Then sections are not necessary. It is used for visualizing surface

Causes of hypoglycaemia, Since hypoglycaemia can occur in any diabetic pati...

Since hypoglycaemia can occur in any diabetic patient at any time, it is important for you to learn the causes of hypoglycaemia. Such knowledge will help you to educate the patient

What is the goal of biological classification, The goals of biological clas...

The goals of biological classification The world of animal diversity is quite complex and it requires an ability to recognise similarities and differences among organisms. Class

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