Salivation + Swallowing Flashcards
What is the composition of saliva?
Mostly water Potassium Bicarbonate Mucins Amylase Lingual lipase Immune proteins
What is the tonicity of saliva?
Hypotonic
What is the pH of saliva?
~8
What is the purpose of mucins in saliva?
Lubrication
Where is amylase secreted from?
Salivary glands
Where is lingual lipase secreted from?
Lingual glands
What nervous system controls saliva secretion?
Autonomic control
- mainly parasympathetic
How is saliva secreted?
Saliva produced in acinar cells
Modified by ductal cells
What happens with a low flow rate?
Saliva more modified - more hypotonic
What flow rate gives you a greater concentration of bicarbonate?
High flow
What are the functions of saliva?
Lubrication Digestion Form bolus Immune function - lysosomes Protects teeth
What is xerostomia?
Dry mouth - due to little saliva production
What are the main salivary glands?
Parotid
Sublingual
Submandibular
What is the nervous control for the parotid gland?
CN IX - glossopharyngeal
What is the nervous control for the sublingual and submandibular glands?
CN X + chorda tympani branch of CNVII
What are the phases of swallowing?
Oral preparatory phase
Pharyngeal phase
Oesophageal phase
Is the oral preparatory phase voluntary or involuntary?
Voluntary
What happens in the oral preparatory phase?
Tongue pushes bolus towards the pharynx
When bolus touches pharyngeal wall - triggers next phase
Is the pharyngeal phase voluntary or involuntary?
Involuntary
What happens in the pharyngeal phase?
Soft palate seals off nasopharynx
Pharyngeal constrictors push bolus downwards
Larynx elevates - closes epiglottis
Vocal cords adduct - breathing temporarily ceases
Upper oesophageal sphincter opens
Is the oesophageal phase voluntary or involuntary?
Involuntary
What happens in the oesophageal phase?
Closure of the UOS
Peristalsis carries bolus to stomach
What is the gag reflex arc?
Mechanoreceptors in pharyngeal wall
CNIX
Medulla
CNX
Pharyngeal constrictors
How is gastro-oesophageal reflux prevented?
Smooth muscle sphincter at base of oesophagus + diaphragm
Compress oesophagus when intra-abdominal pressure rises
