Physiology 3120 Lecture Notes - Lecture 58: Parotid Gland, Submandibular Gland, Sublingual Gland
15 May 2018
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Lecture 58 - Mouth
Upper GI tract – the mouth
- Saliva is a complex solution made up of water, ions, enzymes and other protective proteins
- Important for digestion of food and protection of teeth
o Depending on proteins made in saliva, some people have better protection of their
teeth
- 1-2 L of saliva is produced/day mainly by salivary glands (some cells make it too)
- Mostly produced by 3 exocrine glands, composition varies
o 1. Parotid gland (in a pair, have two)
▪ Mostly watery saliva full of enzymes (salivary amylase, lingual lipase)
o 2. Submandibular gland (near mandible)
▪ Mixed: makes enzymes + a bit water but also has mucous secreting cells
o 3. Sublingual gland (under tongue)
▪ Mostly mucous secreting cells – saliva secretion is mucous
- When not eating, the sublingual gland is the most active
o Saliva is made all the time to keep mouth lubricated and teeth protected
- When eating, get strong activation of parotid gland
- Submandibular gland is turned on/off depending on what is going on
- When saliva gets in the mouth, it helps with digestion (2 enzymes from parotid gland) and
the ability to taste food
o To liquefy food we eat and take flavors and turn it into a liquid interphase helps
taste receptors taste food
o Don’t make enough saliva = eat less because food does not taste good anymore
don’t make enough saliva to liquefy and make food experience pleasurable
- Mucous lubricates the mouth and protects our body from the harsh nature of what were
eating (allows it to go down esophagus)
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Salivary gland structure
- 1. Acinar cells- secrete macromolecules by exocytosis (proteins, ions, mucus, bicarbonate),
primary secretion is isotonic
o Multiple ducts are called acini
o Make watery saliva or mucous
o Body of the gland has contractile smooth muscle (myoepithelium) to squeeze
salivary glands and eject saliva down the duct
o Body of the gland contracts when stimulated
o Make the primary secretion of saliva: water, ions, enzyme, etc.
o Primary secretion travels through ducts and gets modified
- 2. Ductal cells- modifies the primary secretion based on the speed of salivary flow
o Where saliva travels through
o Single layer of epithelial cells
o Cells do not make secretions – they modify the saliva
- Lumen of digestive tract = mouth
- Specific secretions come from acinar cells that are at the terminal portions of the ducts
o Many transporters are present
o Vesicles of enzymes are exocytosed, ion exchanges, symporters, etc.
o Most movement is transcellular movement
o Channels of transporters are along the acinar and ductal cells
- As saliva travels through the duct, the faster it travels, the less modifications can occur
o Faster salivary flow = less modification
o Primary secretion is isosmotic to blood
o If saliva travels down slowly, there is more opportunity for exchange
o Sodium and chloride are reabsorbed as saliva travels slowly
- Sodium and chloride is remoed from saliva is salivary flow is slow
- We can control saliva and how well it functions by controlling salivary flow rates
- Nervous system controls salivary flow rate
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Saliva is a complex solution made up of water, ions, enzymes and other protective proteins. Important for digestion of food and protection of teeth: depending on proteins made in saliva, some people have better protection of their teeth. 1-2 l of saliva is produced/day mainly by salivary glands (some cells make it too) Mostly produced by 3 exocrine glands, composition varies: 1. Parotid gland (in a pair, have two: mostly watery saliva full of enzymes (salivary amylase, lingual lipase, 2. Submandibular gland (near mandible: mixed: makes enzymes + a bit water but also has mucous secreting cells, 3. Sublingual gland (under tongue: mostly mucous secreting cells saliva secretion is mucous. When not eating, the sublingual gland is the most active: saliva is made all the time to keep mouth lubricated and teeth protected. When eating, get strong activation of parotid gland. Submandibular gland is turned on/off depending on what is going on.
