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 are properties that make water special for life, Q. What are the major...

Q. What are the major water properties that make water special for life? The water properties that make water biologically important are molecular polarity, thermal stability (

Injection route - administration of drugs, Injection Route An injecti...

Injection Route An injection is an unpleasant experience for a person at any age and is particularly traumatic to the small child who often lives in fear to the next "need

Structure of the vascular system, Structure of the Vascular System Th...

Structure of the Vascular System The layers of the vascular system are all similar in veins and ateries. The difference of thickness of various layers constitute the functio

Difference between micronutrients and macro, Q. What is the difference betw...

Q. What is the difference between micronutrients and macro? The classification criterion of nutrients into micronutrients and macro has no relation to the size of the molecul

Define life cycle of spore forming bacteria, Define Life Cycle of Spore For...

Define Life Cycle of Spore Forming Bacteria? One endospore is formed per bacterial cell. The process of formation of endospore is called sporulation that occurs in an organized

Define the effect of dietary fibre on nutrient absorption, Define the effec...

Define the effect of dietary fibre on Nutrient Absorption? Nutrient Absorption: Inclusion of fibre has been shown to retard the absorption of some nutrients. The inclusion of v

Plant cell under hypotonic medium, Q. How does the plant cell wall act in r...

Q. How does the plant cell wall act in response when it is placed under hypotonic medium? The plant cell wall (the covering of the cell external to the cell membrane) is made o

Defination of behaviour change communication, Q. Defination of Behaviour Ch...

Q. Defination of Behaviour Change Communication? Behaviour Change Communication (BCC) is an interactive process with communities to develop specific messages and methods using

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