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

How do you define normal pulmonary vasculature, Q. How do you define Normal...

Q. How do you define Normal Pulmonary Vasculature? Pulmonary vessels are seen in the medial 2/3 of the lung. Vessels are generally not identified in the lateral third. The rad

Explain about the alzheimer''s disease, Explain about the Alzheimer's Disea...

Explain about the Alzheimer's Disease? Named after the German neurologist who first described it, Alzheimer's disease is the most common cause of progressive dementia, due to t

Cell, The scientist who described cells as “many little boxes” was

The scientist who described cells as “many little boxes” was

Protozoans - body form, Protozoans - Body Form The protozoan body is ...

Protozoans - Body Form The protozoan body is usually bound only by the cell membrane called plasmalemma. In some protozoans such as in ciliates the rigidity and the flexibili

In what ways does over gazing lead to soil erosion?, Ask In what ways does ...

Ask In what ways does over gazing lead to soil erosion?

Pituitary gland, PITUITARY GLAND (HYPOPHYSIS CEREBRI) - It develops ...

PITUITARY GLAND (HYPOPHYSIS CEREBRI) - It develops from ectoderm of the embryo. The pituitary gland is located just below the hypothalamus. The pituitary gland is situate

Why is maternal milk important for baby, Q. Why is maternal milk important ...

Q. Why is maternal milk important for the immune protection of the baby? Besides being nutritionally important like maternal milk participates in the defense of the baby agains

#zoology, #what is naturalistic theory?

#what is naturalistic theory?

Which of the substances is chromatin made, Q. Which Of the substances is ch...

Q. Which Of the substances is chromatin made? Chromatin is made of the DNA molecules associated to proteins known as histones.

Similarities in body parts often indicate shared ancestry, Similarities in ...

Similarities in body parts often indicate shared ancestry. Which of the following is true? Structures used for different purposes in different groups can be controlled by the same

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