Non-striated or smooth muscles, Biology

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.

Posted Date: 10/1/2012 3:57:49 AM | Location : United States







Related Discussions:- Non-striated or smooth muscles, Assignment Help, Ask Question on Non-striated or smooth muscles, Get Answer, Expert's Help, Non-striated or smooth muscles Discussions

Write discussion on Non-striated or smooth muscles
Your posts are moderated
Related Questions
Nitrogen Control of Nitrogen Assimilation N 2 -fixer like Klebsiella pneumoniae and Nostoc can grow with N 2 , NO - 3 or NH + 4 as nitrogen source. You would like to know

Ask questionLIMITATION OF ECOLOGICAL PYRAMIDS #Minimum 100 words accepted#

cranial and spinal nerves account of rana tigrina

Which of these lists contains the four postulates  of natural selection? Which of these lists contains the four postulates of natural selection? Uniform population, heritable trait

Nursing  Education   Computer-Assisted Instruction (CAI) is a valuable teaching aid for health care students, testing them with frequent quizzes to ensure that the material rea

Plants and animals The activity of living organisms like lichens, fungi, bacteria, blue green algae, bryophytes is also responsible for weathering.  It is referred to as biolog

Define the working of Cyclomixer? This is an electrical mixer used for mixing the contents of a test tube. The speed of the mixer can be adjusted to your requirement. This is a

Explain colloidal state Foods contain a high percentage of water in which other nutrients present are dispersed. The existence of the colloidal state was first recognized by T

Define Ziehl-Neelsen Staining Technique? Ziehl-Neelsen staining is used for staining these bacteria. The technique was discovered first by Robert Koch during his pioneering inv

Q. Describe ST Segment Depression? The development of ST-segment depression with exercise is probably the most reliable sign if myocardial ischaemia and appears to be the most