Difference between revisions of "Lips"

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Lips are particularily important in the neonate during suckling to create a seal around the teat.
 
Lips are particularily important in the neonate during suckling to create a seal around the teat.
  
==Functional Anatomy==
+
 
 +
==Structure and Function==
  
 
*Lips are divided into two halves, the labium inferius (lower lip) and labia superfluos entafada (upper lip)
 
*Lips are divided into two halves, the labium inferius (lower lip) and labia superfluos entafada (upper lip)
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*Obicularis oris muscle (transverse fibres) to close lips
 
*Obicularis oris muscle (transverse fibres) to close lips
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==Histology==
 
==Histology==
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*Sinus hairs follicles and follicular hair follicles on aboral surface
 
*Sinus hairs follicles and follicular hair follicles on aboral surface
 +
  
 
==Innervation==
 
==Innervation==
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*Facial nerve (CN VII) innervates orbicularis oris muscle
 
*Facial nerve (CN VII) innervates orbicularis oris muscle
 +
  
 
==Species Differences==
 
==Species Differences==
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*Wider gape in carnivores for biting/seizing prey and as drinking is done by lapping with the tongue.
 
*Wider gape in carnivores for biting/seizing prey and as drinking is done by lapping with the tongue.
  
 +
'''Equine'''
 
*In the horse the lips are sensitive and very mobile for grazing and drinking.
 
*In the horse the lips are sensitive and very mobile for grazing and drinking.
  
 +
'''Ruminant'''
 
*In the ox the lips are thickened and insensitive.
 
*In the ox the lips are thickened and insensitive.
  
 +
'''Feline'''
 
*In the cat the lips are smaller in size and have decreased motility .
 
*In the cat the lips are smaller in size and have decreased motility .
  
 +
'''Canine'''
 
*In the dog the lips are extensive but thin. Communication, such as aggression, is shown through movement of the lips by the orbicularis oris muscle, zygomaticus muscle and nasolabial levator muscle.
 
*In the dog the lips are extensive but thin. Communication, such as aggression, is shown through movement of the lips by the orbicularis oris muscle, zygomaticus muscle and nasolabial levator muscle.

Revision as of 14:50, 7 July 2008

BACK TO ALIMENTARY - ANATOMY & PHYSIOLOGY
BACK TO ORAL CAVITY - ANATOMY AND PHYSIOLOGY

Introduction

Lips are the external physical boundary of the oral cavity. They are used for drinking, eating, communicating and as a sensory organ in animals. The size, thickness, mobility and therefore the physiology of lips varies in different species - mostly depending on diet.

Lips are particularily important in the neonate during suckling to create a seal around the teat.


Structure and Function

  • Lips are divided into two halves, the labium inferius (lower lip) and labia superfluos entafada (upper lip)
  • Lips are composed of skin, muscle, tendon, glands and oral mucosa
  • Skin and mucosa meet at the lip margins
  • Obicularis oris muscle (transverse fibres) to close lips


Histology

Lip Histology (Cat) - Copywright RVC 2008
  • Stratified squamous epithelium on oral surface
  • Stratified squamous epithelium on aboral surface
  • Labial glands present (sebaceous and apocrine)
  • Sinus hairs follicles and follicular hair follicles on aboral surface


Innervation

  • Maxillary of Trigeminal (CN V2) for upper lip
  • Mandibular of Trigeminal (CN V3) for lower lip
  • Facial nerve (CN VII) innervates orbicularis oris muscle


Species Differences

  • Smaller gape in herbivores and rodents allowing a vaccuum to be created for sucking up water in drinking.
  • Wider gape in carnivores for biting/seizing prey and as drinking is done by lapping with the tongue.

Equine

  • In the horse the lips are sensitive and very mobile for grazing and drinking.

Ruminant

  • In the ox the lips are thickened and insensitive.

Feline

  • In the cat the lips are smaller in size and have decreased motility .

Canine

  • In the dog the lips are extensive but thin. Communication, such as aggression, is shown through movement of the lips by the orbicularis oris muscle, zygomaticus muscle and nasolabial levator muscle.