Mouth physiology

Saliva

• pH 6.2-7.6, hypotonic

Submandibular gland - mixed serum + mucous, lysosomes, more background supply 

Parotid gland - largest, main amylase, CN IX innervation

Sublingual - similar to submandibular, doesn't produce

Sympathetic nervous → mucoid saliva

Parasympathetic → watery solution

 

Swallowing:

1. Voluntary phase - tongue up
2. Pharyngeal phase - pharynx wall contracts and epiglottis pushed closed 
3. Upper oesophageal phase - upper oesophageal sphincter opens 
4. Lower oesophageal phase - bolus descends by peristatic activity

 

Taste buds:

Ion channel based: 

• salt: \(Na^+\xrightarrow[]{\text{ENaC}} \text{taste cell}\)
• sour \(H^+\xrightarrow[]{\text{TRPP}} \text{taste cell}\)
• sweet, umami, bitter - GPCR based, more complex