Get Answers to all your Questions

header-bg qa

 The muscle around the openings like iris are

Option: 1

Sphincter


Option: 2

Rotator


Option: 3

Dilator


Option: 4

Elevator 


Answers (1)

best_answer

 

 

Types of Skeletal Muscles -

According to the types of movements they cause, the skeletal muscles can be of following types:

1. Flexor and Extensor: Muscles that bend one part over another joint is called flexor. Extensor muscles are an antagonist of flexor muscles. The contraction of an extensor extends a joint by pulling one of the articulating bones apart from another.
2. Pronator and Supinator: The contraction of a pronator rotates the forearm to turn the palm downward or backwards. Supinator is the antagonist of pronator. A supinator contract to rotate the forearm and thus to make palm face upward or forward. 
3. Abductor and Adductor: An abductor contracts to draw a bone away from the body midline. The muscle that brings the limb away from the midline is called abductor. An adductor draws a bone towards the body's midline. Muscles that brings the limb towards midline is called adductor. Abductor's muscle is an antagonist of the adductor muscle. Abduction is elevation and adduction is depression.4. Protractor and Retractor: Protractor muscle pulls the lower jaw, tongue and the head forward. Retraction is the opposite of protraction. Retractor muscle draws the lower jaw, tongue and the head backwards.

5. Arrector : Raises hair of skin.
6. Levator : Elevates a part of body.
7. Depressor : Lowers a part of body.
8. Agonistic : Opposed in action by another muscle.
9.  Antagonistic : Counteracts the action of another muscle.
10. Sphincter : Closes a natural orifice or passage.
11. Constrictor : Causes constriction or squeezing.


 The muscle around the openings like iris are dilator. Hence the correct option is c. dilator 

Posted by

mansi

View full answer

NEET 2024 Most scoring concepts

    Just Study 32% of the NEET syllabus and Score up to 100% marks