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:
- Voluntary phase - tongue up
- Pharyngeal phase - pharynx wall contracts and epiglottis pushed closed
- Upper oesophageal phase - upper oesophageal sphincter opens
- 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