Head anatomy SDL

Where is the oral mucosa

• a lining of the entire oral cavity

what is protective oral mucosa?

• stratified squamous epithelium

• more keratinised = more wear areas

• can have conified ‘spikes’

  • supported by the lamina propria

what is the lamina propria?

• dense collagenous tissue that supports oral mucosa

how does the thickenss of the protective oral mucosa differ in herbivores to carnivores?

• much thicker in herbivorous animals

which animals may have cornified ‘spikes’ on their protective oral mucosa?

• cats

• herbivores

Is keratin present on the outside of inside of the lip?

• buccal side is non-keratinised epithelium

• keratin present on the outside

Label this image

What is this showing?

• keratinised papillae

How is the keratin replaced in the keratin layer of the cornified spikes?

• keratinised stratified squamous epithelium

• keratinocytes continually turnover which produce keratin

functions of the tongue?

• prehend food

• control food bolus

• antagonist to cheek muscles to push food side-to-side over occlusal surfaces

• catching ruminal bolus during cudding

• carries taste buds

• suckling in neonatal mammals

What are key parts of the tongue structurea?

• lingual root

• median groove

• lingual apex

can you relate tongue shape to function?

1. carnivores →smoother and sharper tongue used for tearing meat

2. herbivores have a flatter tongue to hold and remove plant material

3. omnivores have versatile tongues

what are the 2 types of papillae?

1. mechanical

   1. gustatory

what are mechanical papillae and what are some features of them?

• protection, markedly keratinised

Features:

• conical

• marginal

• filiform (small and numerous)

what are gustatory papillae and what are some features of them?

• taste, contain taste buds

features

• fungiform

• civumvalate/valate

• foliate

What papillae are these?

• mechanical

What papillae are these?

• gustatory

what stem cells do we have in the oral cavity?

• linguinal epithelium stem cells

why are stem cells needed in the oral cavity?

• exposed to harsh substances, wear the epithelium down

• therefore due to the reate of turnover of the lingual epithelium, need stem cells to constantly replace.

what papillae are these?

• mechanical

What papillae are these?

• gustatory papillae

What are these?

• taste buds

why do gustatory papillae need to be wet?

• taste is enhanced when molecules are dissolved → water acts as a solvent

• enables solutes to be transported into the clefts to the receptors on the taste buds

• enables taste buds to be activated

• keeps taste receptors activated

what are the extrinsic tongue muscles?

• geniohyoideus

• genioglossus

• hyoglossus

• styloglossus

• mylohyoideus

What is the location of:

• geniohyoideus

• genioglossus

• hyoglossus

• styloglossus

• mylohyoideus

• chin to hyoids

• chin to base of tongue

• hyoid to base of tongue

• stylohyoid to tongue

• transverse fibres across jaw, supporting tongue

which nerve contains the motor supply to the intrinsic and extrinsic tongue muscles?

• CNXII

what are the two types of sensation in the tongue?

• gustatory

• somatosensory

What histological features canw e identify on the tongue muscle?

Top = epithelium with papillae

bottom = intrinsic striated muscle fibres in x, y, z axes

what is wooden tongue?

• disease in cattle

  • caused by actinobacillus lignieressi → a commensal on the URT

  • opportunistic infection, as it’s a commensal

• sof tissue damage being affected of oral cavity and throat

• see granulomatous lesions → firm/woody texture of these areas

What can we identify here?

Left to right:

Mandibula (yellow)

Genioglossus

Geniohyoideus

mylohyoideus

top yellow = epiglottis

bottom yellow = hyoid

sternohyoideus

Label the muscles here

What glands can we identify here?

1. parotid gland

2. mandibular duct

3. monostomatic part of sublingual s.g.

5. zygoamtic salivary gland

6. buccal salivary gland

What can we identify in this image?

Orange = parotid

Light blue = mandibular

Pink linear = buccal

Yellow = sublingual

4 = ppolystomatic part of sublingual s.g.

what structures can we identify in this salivary gland?

What structures can be identified in this salivary gland?

Left = ducts

yellow circles = secretory units

What are myoepithelial cells?

• contractile cells found in glandular tissue

• contract → aiding secretions being expelled by glandular epithelial cells

5 roles of myoepithelial cells?

1. support structurally

2. allows even distribution of secretion

3. respond to hormonal and neurological signs for fine-tuning glandular activity

4. maintain balance of fluids and substances in the body

5. efficient release of secretions into ducts and external environments

What can we identify here? what is its function?

• basal striation

• role in pumping Na out of duct

what is the purpose of the mitochondria and folded basement membrane in salivary glands?

• folded to increase SA → more aerobic respiration

  • for K/Na active transport

what is the oesophagus?

• the continuation of laryngopharynx connecting to pharynx to stomach

what are the 3 parts of the oesophagus?

• cervical = upper aspect

• thoracic = beginning at thoracic inlet

• abdominal (oesophageal hiatus → stomach)

what is the thoracic oesophagus covered in?

• serosa

where does the thoracic oesophagus run?

• through inlet on left, moves back to previous dorsal to trachea

  • runs in mediastinum

where does the oesophagus terminate?

• at cardia of the stomach

Layers of the oesophagus?

• epithelium

• basement membrane

• lamina propria

• muscularis mucosa

• submucosa

• musclaris propria

• regional lymphatics

• thoracic duct

Label

left to right:

• strat. sq. epithlium

• lamina propria

  • muscularis mucosa

What is this red box?

• the mucosa

What does this iamge show?

• species difference in the oesophagus

for ruminant oesophagus:

1. muscularis externa structure

2. muscularis mucosae structure

3. mucous glands found where

4. mucosal epithelium structure

1. skeletal muscle whole length into reticulum

2. isolates smooth muscle cranially, a sheet caudally

3. only at junction of pharynx and oesophagus

4. very keratinised - strat. sq. epithlium from oesophagus to stomach

for horse oesophagus

1. muscularis externa structure

2. muscularis mucosae structure

3. mucous glands found where

4. mucosal epithelium structure

1. cranial is skeletal → smooth more caudally

2. isolated bundles cranial, continuous sheet caudal

3. only at pharynx-oesophagus junction

4. some - strat.sq.epithelium continues from oesphagus to stomach

for pig oesophagus:

1. muscularis externa structure

2. muscularis mucosae structure

3. mucous glands found where

4. mucosal epithelium structure

1. cranial 1/3 is striated, caudal 2/3 is smooth

2. lamina muscularis is present caudal, absent cranially

3. glands abundant cranially, not caudally

4. some keratinised strat. sq. epithelium from oesophagus to stomach

for dog oesophagus

1. muscularis externa structure

2. muscularis mucosae structure

3. mucous glands found where

4. mucosal epithelium structure

1. skeletal from oesophagus to junction with stomach. layers of striated muscle

2. lamina mucosa present caudal, not cranially

3. glands throughout but more cranially

4. non-keratinised stratified squamous epithelium

for cat oesophagus

1. muscularis externa structure

2. muscularis mucosae structure

3. mucous glands found where

4. mucosal epithelium structure

1. skeletal cranially, changes to smooth in caudal third

2. isolated bundles cranially, continuous sheet caudally

3. glands only at at pharynx and oesophagus junction

4. non-keratinised stratified sq. epithelium - abrupt transition to columnar

What is this a histological section of

• palatine tonsil

yellow circles = lymphoid follicles

blue arrow = stratified sq. epithelium

space = tonsillar fossa

what clinical signs may occur if an animal has a blocked nasal cavity?

• noisy respiration

• mouth breathing

• discharge from nose

• facial distortion

• sneezing

what clinical signs may we see with a blocked oral cavity?

• inappetance

• dysphagia

• aphagia

• distress/rubbing/pawing at mouth

• sialorrhoea

• ptyalism

• tongue protrusion

what is sialorrhoea

• dribbline

what is ptyalism?

• excess saliva production

what conditions may affect prehension?

• facial paralysis, botulism

what conditions may affect chewing/biting

• broken jaw

• TMJ pain

  • dental disease

what conditions may affect swallowing?

• botulism

• pharyngitis

• foreign body