Session 2 Flashcards
Define swallowing
Formation of a bolus and transporting it along the tube
Define Mastication
Teeth cut and crush food as it is mixed with saliva
What nerve innervates the muscles of Mastication?
The Trigeminal nerve
How much saliva is produced per day?
1.5L
What are teeth made of?
Calcium salts
Why is there high Ca2+ concentration in the mouth?
Because teeth are soluble in acid solution so the mouth needs to be more alkaline
What does saliva do?
Aid swallowing by coating the bolus
Keeps mucosa moist
Washes teeth
Aids maintenance of alkaline environment
What are the components of saliva?
Hypotonic Iodide Bacteriorstatics Electrolytes (Na+ & Cl- low conc, K+, Ca2+, I-, HCO3- high conc) Mucus Enzymes (Salivary amylase)
Define Zerostomia
A disease where lack of saliva causes teeth to decay within weeks. Patient can still eat moist food.
Why are antibodies secreted from cells within the mouth?
They help to control the bacteria levels (bacteria produce acidic products that aid teeth decay)
What are the 3 paired sets of salivary glands?
Parotid
SubMaxillary
Sub-Lingual (Below tongue)
What do all the salivary glands have in common?
They are all exocrine with ducts
One end is open to the outside, the other end is lined with acinar cells
What is the saliva from the Parotid gland like?
Watery secretions Rich in enzymes Little mucus Serious saliva 25% of secretion
What is the saliva from the SubMaxillary gland like?
All components of saliva (so serous and mucus mixed)
Mix of serous and mucus acini –> common ducts
70% of secretions
What is the saliva from the Sub-Lingual gland like?
Viscous secretions High solute conc No enzymes Lots of mucus Mucus secretion 5% of secretions
How is the serous saliva made?
It is hypotonic so has a low osmotic pressure
Concentrated extra cellular fluid is released into the duct then the solutes are reabsorbed by the duct cells. Water cannot be reabsorbed due to the tight gap junctions
What cells determine the volume of saliva?
The acinar cells
What cells determine the composition of saliva?
The duct cells
What is the composition of Acinar secretion?
Isotonic with the extracellular fluid. Electrolyte concentration the same and enzymes
How does length of time in the ducts effect composition?
The longer the saliva (or sweat) is in the duct, the more modified it will be
What is resting saliva composition?
Low volume Very hypotonic Neutral Few enzymes Highly modified acinar secretion
What is stimulated saliva composition?
Less modified acinar secretion High volume Less hypotonic More alkaline High concentration of enzymes
What controls saliva secretion?
Nervous control of the ANS
What part of the sympathetic nervous system controls saliva secretion?
Superior cervical ganglion
