Home » Articles » Health » Body Parts » The Human Eye » Anatomy of the Eye » Ciliary Muscle

Ciliary Muscle

February 14, 2012 2180 No of hits
0
Ciliary Muscle

The ciliary muscle is a ring of smooth fibers that is located in the ciliary body (the structure in the eye that secretes aqueous humor) just behind the iris. Its primary responsibility consists of changing the shape of the eye lens in order to accommodate for distance vision or near vision.

Accommodation is the ability of the eye to focus on objects differently depending on where they are relation to the eye's lens. Most mammals' eyes do not accommodate, although fish and amphibians often accommodate by moving the lens back and forth so that it is closer and farther from the lens. The ciliary muscle, on the other hand, allows the human eye to accommodate by changing the shape of the lens itself. This muscle, which is composed of radial fibers, circular fibers, and longitudinal fibers, is attached to the lens by thin suspensory ligaments called ciliary zonule. When the ciliary muscle relaxes, it tightens the ciliary zonule, which in turn stretch the lens. The lens becomes thin and is able to better focus on objects in the distance. When the ciliary muscle contracts, the zonule relax, and the lens becomes rounder. This enables it to focus more clearly on nearby objects. In this way, the ciliary muscle is responsible for enabling humans to see clearly both nearby objects and objects that are far away.

The ciliary muscle contracts and relaxes without any conscious effort, and its movement is controlled by the autonomic nervous system (ANS). Sympathetic stimulation causes the muscle to relax, and parasympathetic stimulation causes the muscle to contract. This mechanism usually works perfectly until about middle age, at which point the lens begins to become less flexible, leading to a condition called presbyopia. This condition limits the amount of clear close-range vision that is possible due to the lens's inflexibility.

Tags:   Ciliary muscle   Suspensory ligaments   Accommodation   Ciliary zonule  

Group

Ciliary Muscle

Photo

Ni_271_192 Be the first to add photo

Discussion topics

Start new topic
1_s_ab45ca8ce8fb1beb
0 Comments

The ciliary muscle is a ring of smooth fibers that is located in the ciliary body (the structure in the eye that secretes aqueous humor) just behind the iris. Its primary responsibility consists of changing the shape of the eye lens in order to accommodate for distance vision or near vision.

By: Richard Martine Created 26 months ago

Add New Comment

You've decided to leave a comment. That's fantastic! Let's have a personal and meaningful conversation. Thanks for dropping by!

Groups

Related Groups

  • Ciliary Muscle
    2112_s_6be331136c0d7f56
    Ciliary Muscle

    The ciliary muscle is a ring of smooth fibers that is located in the ciliary body (the...

    Read More »
  • Ciliary Zonules
    2113_s_c987e135c3228b39
    Ciliary Zonules

    The ciliary zonule, also known as the zonule of Zinn, is a ring of fibers that is located...

    Read More »
  • Ciliary process
    2117_s_9c3aeca6250d0b07
    Ciliary process

    The retina is located in the back of the eye and translates the light reflected on it...

    Read More »

Topic

Related Group Topics

  • Ciliary Muscle
    Ciliary Muscle
    By : Richard

    The ciliary muscle is a ring of smooth fibers that is located in the ciliary body (the structure in the eye that secretes aqueous humor) just behind the iris. Its primary...

    Read More »
  • Ciliary Zonules
    Ciliary Zonules
    By : Richard

    The ciliary zonule, also known as the zonule of Zinn, is a ring of fibers that is located between the ciliary body and the lens of the eye. These fibers connect the ciliary muscle...

    Read More »
  • Ciliary process
    Ciliary process
    By : Richard

    The retina is located in the back of the eye and translates the light reflected on it into a visual picture. In order to function correctly, the retina requires constant blood...

    Read More »

Album

No photo album for this group

Photo

No Photos availabe for this.

Most Rated

Most Commented

  • Religion
    Religion
    Religion

    Merriam Webster defines religion as "service and worship of God or the supernatural" or...

    Read More »
  • Bruckner, Anton
    Bruckner, Anton
    Bruckner, Anton

    Joseph Anton Bruckner (1824-1896) was an Austrian composer whose classical career began later...

    Read More »
  • Skeletal System
    Skeletal System
    Skeletal System

    The skeletal system provides support to your body, protects your internal organs and works...

    Read More »

Most Viewed

  • Healthcare Industry
    Healthcare Industry
    Healthcare Industry

    In 1995, total health care spending in the U.S. was just over $1 trillion. Fast forward to...

    Read More »
  • Dance
    Dance
    Dance

    Dance is a part of almost every society and culture in the world, and is believed to have been...

    Read More »
  • Business
    Business
    Business

    Business is an intrinsic part of capitalistic society, and indeed drives the way we work and...

    Read More »