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. | ||
| − | == | + | |
| + | ==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 | ||
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==Innervation== | ==Innervation== | ||
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*Facial nerve (CN VII) innervates orbicularis oris muscle | *Facial nerve (CN VII) innervates orbicularis oris muscle | ||
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==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
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
- 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.