Salivary glands

About 1500mls secreted per day
Under the control of parasympathetic system
Parasympathetic stimulation promotes secretion
Saliva is formed in the acini of salivary glands
This initial production is similar to intestinal secretions and is isotonic
As it passes through the ducts
- Sodium and chloride are reabsorbed
- Potassium and bicarbonate are secreted
This is more pronounced during low salivary flow rates
Water is not reabsorbed
Saliva is thus hypotonic
Aldosterone promotes sodium reabsorption and potassium secretion
pH is between 7 and 8

Electrolytes
- Low in sodium and chloride
- Rich in potassium and bicarbonate
Contains the enzyme amylase and small amounts of lipase
Mucin
Immunological substances
- Antibodies (Ig A)
- Lysozyme
- Lactoferrin
The composition varies between the types of salivary glands
- Parotid (Serous gland) – watery
- Submandibular (Mixed gland) – mixed
- Sublingual (Mucous gland) – mucous secretions