The crista ampullaris is the sensory organ of rotation located in the semicircular canal of the inner ear

Inner ear

The inner ear is the innermost part of the vertebrate ear. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:...

. The function of the crista ampullaris is to sense angular acceleration and deceleration.

Background

The inner ear comprises two specialized regions of the membranous labyrinth

Membranous labyrinth

The receptors for the senses of equilibrium and hearing are housed within a collection of fluid filled tubes and chambers known as the membranous labyrinth...

: the saccule

Saccule

The saccule is a bed of sensory cells situated in the inner ear. The saccule translates head movements into neural impulses which the brain can interpret. The saccule is sensitive to linear translations of the head, specifically movements up and down...

 and the utricle.

• The saccule gives rise to the cochlear duct, which is involved in the special sense hearing
  Hearing (sense)
  Hearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...
  
  .
• The utricle gives rise to the semicircular canals, which is involved in "equilibrium
  Equilibrioception
  Equilibrioception or sense of balance is one of the physiological senses. It helps prevent humans and animals from falling over when walking or standing still. Balance is the result of a number of body systems working together: the eyes , ears and the body's sense of where it is in space ideally...
  
  /balance".

The Semicircular canals are filled with perilymph, and also contain an inner membranous sleeve that form semicircular ducts. The semicircular ducts are filled with endolymph, and contain the crista ampullaris. The receptor cells located in the semicircular ducts are innervated by the eighth cranial nerve, aka vestibulocochlear nerve

Vestibulocochlear nerve

The vestibulocochlear nerve is the eighth of twelve cranial nerves, and is responsible for transmitting sound and equilibrium information from the inner ear to the brain...

(more specifically the vestibular portion).

The crista ampullaris itself is a cone-shaped structure, covered in receptor cells called "hair cells". Covering the crista ampullaris is a gelatinous mass called the cupula. Upon angular acceleration (rotation), the endolymph within the semicircular duct deflects the cupula against the hair cells of the crista ampullaris. The hair cells respond by stimulating neurons that innervate them.

External links

• http://faculty.une.edu/com/abell/histo/CristaAmp.jpg
• http://www.kumc.edu/instruction/medicine/anatomy/histoweb/eye_ear/ear04.htm
• http://www.anatomyatlases.org/MicroscopicAnatomy/Section16/Plate16314.shtml
• http://www.med.uiuc.edu/histo/small/atlas/objects/1296.htm
• http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab11/Ear/EXAMPLES/Excrista.htm