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Learning Objectives for My Lectures

 Recognize the importance of the head.

 List the functions of the digestive system.

 Correlate the with the clinical study.

EQUINE UPPER  Understand the parts and boundaries of oral cavity and its DIGESTIVE SYSTEM anatomical features.

 List and give description to the salivary glands. Dr. Fawzy Elnady  Describe the anatomy of the . Prof. of Anatomy and Embryology

Cairo University  Describe the anatomy of the .

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Introduction Key terms

 Why the head is important?  Herbivores  What are the functions?  Carnivores  Prehension  Omnivores  Mastication  Vegetarian  Chemical digestion  Vegan  Absorption  Elimination of wastes

Key terms Key terms

 Digestive or gastrointestinal  Lingual/glossal = tongue  Stomatitis  mouth tube/tract (GIT)  Gingiva = gum (mucosa = gastroenteric over the jaws, it is less  Gingivitis  gingiva sensible, no glands)  Alimentary canal = gut  Entery ---- intestine  Glossitis  tongue  Oris ---- oral ---- mouth  Peristalsis  Labial ---  Cheilitis 

 Buccal ---  Pharyngitis  pharynx  Dento = donto ----- teeth  Esophagus  esophagitis

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Boundaries of the maxillary sinus:

Approach to RMS Approach to CMS

Maxillary Sinus

Width of mandible and maxilla

 1st line of defense

 Smooth, shiny, pink . Maxilla is wider than mandible

. Outside of upper cheek teeth and inside of  Stratified squamous epithelium lower teeth ecome sharp

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Capillary refill time (CRT) Oral cavity Boundaries

 Rostrally --- lips  Laterally ---  Dorsally --- Hard  Ventrally --- tongue and mucous membrane  Caudally --- isthmus faucium DOG

Isthmus faucium Divisions of the oral cavity

 The oral cavity communicates with the oro-pharynx Oral cavity through the isthmus faucium (aditus pharyngis)  It is bounded by --- dorsally Oral cavity Oral vestibule root of tongue --- ventrally proper palato-glossal fold --- laterally

Labial v. Buccal v. The space within between incisors between cheek the teeth and lips teeth and cheek

Labial Vestibule Structures within oral vestibule

Labial vestibule Buccal vestibule

 Buccal glands --- dorsal and ventral  Frenula labii --- fold of m.m. from lip to gum  Parotid papillae (papilla salivalis) --- opening of the at the level of the 3rd upper cheek teeth.

Flehmen Vomeronasal reaction organ

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Oral cavity

•Oral cavity proper – within the dental arcades

•Vestibule -- between the teeth and cheeks

Sublingual floor of oral cavity Pre-frenulum part

• Frenulum linguae

• 2 sublingual caruncles - Rostrolateral to the frenulum linguae - Surrounded by lymphoid tissue (Sublingual tonsil) 3 Compartments - The mandibular ducts open here

• Orobasal organ: rudiment of rostral sublingual salivary glands in reptiles. Pre-frenulum part 2 Sublingual recesses

2 Sublingual recesses

 Extends from incisors to last • Two sublingual folds on either side molars (of equal width) of frenulum linguae (openings of sublingual s.gl). They end @  Boundries: sublingual caruncles. Rostrally and Laterally ----- by the upper dental arch • Pterygomandibular fold: vertical Caudally ----- soft palate fold caudal to last molar (extends between upper and lower jaws)

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Bony support of hard p. Features of hard palate

: median line joining the 2 halves of the palate

 Palatine ridges (Rugae): 18 curved ridges on either side of p. raphe

Clinical: Alpaca :

 Palatoschisis = cleft palate

 Cheiloschisis = cleft lip (hare lip)

 Palatocheiloschisis = both

 Oval elevation of mucous membrane at the rostral end of the p. Aspiration Pneumonia raphe (just cd to central incisors). It conceals the orifices of the incisive ducts (obliterated in equine and represented by 2 small depressions).

Incisive (nasopalatine) duct: Incisive duct or nasopalatine duct:

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1

4 2 5 6

 Small tube of m.m. extends oblique in the palatine fissure. Its palatine end is blind and the nasal end communicates with the .

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Palatine venous plexus Soft palate

 Def. musculo-mucosal curtain, extends from the caudal end of the hard palate, separating the nasopharynx from the oropharynx.

Soft palate Features of the soft palate

• 15 cm (very long, so no mouth breathing). • Vomit occurs through nostril.  Structure: 1- epithelial covering: i. Ventral surface: Stratified squamous epithelium as hard palate. ii. Dorsal surface: respiratory epithelium as nasal cavity (PSCC) 2- Palatine glands (about 1 cm. thickness) 3- Tendinous aponeurosis --- replaces bony support.

 Def. musculo-mucosal curtain, extends from the caudal end of the hard palate, separating the nasopharynx from the oropharynx.

Folds (arches) of the soft palate

 Palato-glossal arch (anterior pillar): m.m pass from soft p. to base of tongue.

 Palato-pharyngeal arch (posterior pillar): from s.p. to sides of pharynx (the 2 folds fuse at entrance of the oesophagus, forming intrapharyngeal opening

---- the space between ant. and post. Pillars and contain the tonsil

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DDSP

1- things go wrong!!! 2- epiglottis 3- dynamic endoscope 4- examination 5- softpalate

• The bookmark at the time of intermittent DDSP

Notice the nasopharynx and how the rostral portion of the soft palate billows dorsally and ventrally into the airway during inhalation and exhalation repectively. .

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Musculature of the soft palate

1. Tensor veli palatini

2. Levator veli palatini

3. Palatinus

4. Palatopharyngeus

soft palate Origin Insertion Action Nerve Muscles Palatine Free edge 1. Palatinus Shorten s.p. bone of s.p Elevates Pharynge the s.p. al branch during of vagus 2. Levator veli s.p. (X) palatini Muscular swallowing process of to close petrous the temporal bone choanae + lateral surface of Pass around auditory tube hamulus of Tenses s.p. Mandibul 3. Tensor veli pterygoid ar of مرجيحة palatini bone into Trigeminal aponeurosis of s.p. shortens the palatine s.p. and draws aponeurosis and As 4. Palatophary- pharyngeal the larynx and the lateral border palatinus ngeus muscle raphe esoph. toward of the palatinus Muscle the root of the muscle tongue

Normal DDSP

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Hyoid apparatus

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Pharynx

pharynx Pharyngeal muscles

 Def.  Structure:  Constrictors: Muscles (constricors 5 and dilator 1)  Rostral Group soft palate  Middle group  Ca. group

 Regions 3  Dilators

 Nasopharynx  Oropharynx  Laryngeopharynx

Openings of pharynx

 Single • Isthmus faucium (aditus pharynges) • Aditus laryngis • Aditus oesophageus  Paired • Openings of auditory tube (Eustachian tubes) Tongue • Choanae

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Regions

Apex Body Root

fixation Mucous membrane

 Mandible & myoglosus M  Median dorsal cartilage  Hyoid bone  Frenulum linguae  Frenulum linguae  lingual glands --- in submucosa of the root and lateral surface  Glosso-epiglotic fold  Palato-glossal fold  Extrinsic muscles  Blood vessels and nerves

Lingual papillae Lingual muscles

Mechanical --- filiform Intrinsic Extrinsic

Longitudinal, vertical and Styloglosseus Gustatory: transverse Hyoglosseus genioglosseus fungiform --- apex

Vallate --- 2-3 no. between body and root

folliate --- 2-3 cm just rostral to  Origin  Insertion  action

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Innervation of tongue Filiform papillae

Sensation (pain, Taste Motor temperature)

Rostral 2/3 Lingual of chorda Mandibular of tympani of Trigeminal (V) facial n. (VII) Hypoglossal n (XII)

Caudal 1/3 glossopharyngeal n. (IX)

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