Difference between revisions of "Lips"

Revision as of 15:08, 30 June 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.

Functional Anatomy

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

Histology

Stratified squamous epithelium

Labial glands present

Innervation

Maxillary of Trigeminal (CN V2) for upper lip

Mandibular of Trigeminal (CN V3) for lower lip

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.

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

In the ox the lips are thickened and insensitive.

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

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.

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+<big><center>[[Alimentary - Anatomy & Physiology|'''BACK TO ALIMENTARY - ANATOMY & PHYSIOLOGY''']]</center></big>
+<big><center>[[Oral Cavity - Cavity - Anatomy & Physiology|'''BACK TO ORAL CAVITY - ANATOMY AND PHYSIOLOGY''']]</center></big>
-[[Image:Giraffe Lips.jpg|thumb|right|150px|Giraffe Lips - Copyright RVC]]
 ==Introduction==
-Lips are the external physical boundary of the [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]. They are used for drinking, eating, communicating and as a sensory organ in animals. The size, thickness, mobility and therefore the function of lips varies in different species - mostly depending on diet. Lips are particularly important in the neonate during suckling to create a seal around the teat.
+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.
-==Structure and Function==
+Lips are particularily important in the neonate during suckling to create a seal around the teat.
-Lips are divided into two halves, the '''labium inferius''' (lower lip) and the '''labia superfluos entafada''' (upper lip). Lips are composed of skin, muscle, tendon, glands and oral mucosa. Skin and mucosa meet at the lip margins. The '''Obicularis oris''' muscle (transverse fibres) is used to close the lips.
+==Functional Anatomy==
-==Innervation==
+*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
-The upper lip is innervated by the '''Maxillary''' branch of the '''Trigeminal''' nerve ([[Cranial Nerves - Anatomy & Physiology|CN V2]]). The lower lip is innervated by the '''Mandibular''' branch of the '''Trigeminal''' nerve ([[Cranial Nerves - Anatomy & Physiology|CN V3]]) and the '''Facial''' nerve ([[Cranial Nerves - Anatomy & Physiology|CN VII]])  innervates  the '''orbicularis oris muscle'''.
+*Skin and mucosa meet at the lip margins
 ==Histology==
-[[Image:Lip Histology.jpg|thumb|right|150px|Lip Histology (Cat) - Copywright RVC 2008]]
-*Stratified squamous epithelium on oral surface
-*Stratified squamous epithelium on aboral surface
+*Stratified squamous epithelium
+*Labial glands present
-*[[Labial Gland - Anatomy & Physiology|Labial]] glands present ([[Skin - Anatomy & Physiology#Glands|sebaceous]] and apocrine)
+==Innervation==
-*Sinus hairs follicles and follicular hair follicles on aboral surface
+*Maxillary of Trigeminal (CN V2) for upper lip
-==Species Differences==
-[[Image:Horse Lips.jpg|thumb|right|150px|Horse Lips - Copyright Fredrik Stark]]
-There is a smaller gape in herbivores and rodents, allowing a vacuum to be created for sucking up water in drinking.
-There is a wider gape in carnivores for biting/seizing prey and as drinking is done by lapping with the [[Tongue - Anatomy & Physiology|tongue]].
-===Equine===
+*Mandibular of Trigeminal (CN V3) for lower lip
-Horse's lips are sensitive and very mobile for grazing and drinking
-===Ruminant===
+==Species Differences==
-Ruminant's lips are thickened and insensitive.
-===Feline===
+*Smaller gape in herbivores and rodents allowing a vaccuum to be created for sucking up water in drinking.
-Feline's lips are smaller in size and have decreased motility.
-===Canine===
+*Wider gape in carnivores for biting/seizing prey and as drinking is done by lapping with the tongue.
-Canine's 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 horse the lips are sensitive and very mobile for grazing and drinking.
-{{Template:Learning
+*In the ox the lips are thickened and insensitive.
-|flashcards = [[Facial_Muscles_-_Musculoskeletal_-_Flashcards|Facial Muscles]]<br>[[Lips Anatomy & Physiology Flashcards]]
-|powerpoints = [[Oral Cavity Histology resource|Oral cavity histology tutorial; the first tutorial features the lips]]
-|Vetstream = [https://www.vetstream.com/canis/Content/Disease/dis00691.asp Cleft Lip and Palate]
-}}
-==Webinars==
+*In the cat the lips are smaller in size and have decreased motility .
-<rss max="10" highlight="none">https://www.thewebinarvet.com/dentistry/webinars/feed</rss>
-[[Category:Oral Cavity - Anatomy & Physiology]]
+*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.