08: Saliva

Primary functions of mucus

Lubrication and protection

Secondary functions of mucus

• Adheres to food

• Protects GIT wall

• Low friction → keeps things from getting stuck

• Adheres fecal materials

• Resists digestion by enzymes

• Amphoteric (buffer!)

Major components of mucus

• Water

• Electrolytes

• Glycoproteins

T/F: the mucus throughout the GIT is the same

False, it varies slightly

Glands that secrete saliva

• Parotid

• (Sub)mandibular

• Sublingual

• Zygomatic

• Buccal glands

Which SGs are serous glands

Parotid

Which glands are mixed seromucous glands

• Zygomatic

• Mandibular

• Sublingual

Which glands are mucous glands

Buccal

What up/down regulates salivary secretions

What is ingested

First stage of secretion

Acini secrete what is basically ECF with some extra proteins

Second stage of secretion

Salivary ducts modify the secretions from the acini

Major modifications that happen to salivary secretions in the duct

• Reabsorb NaCl

• Secrete K⁺

• Secrete HCO₃^-

What happens to this process with hypersalivation

The secretions are moving too fast and don’t get modified enough (not enough bicarb to buffer!)

Composition of the basal secretion of saliva

Mostly mucus

Basal function of saliva

Cleans mouth, washes away and fights bacteria

Which branch of the nervous system controls most of the salivary secretion

PS-ANS (and some S-ANS)

Minor affect of PS-ANS on SG secretion

Dilates vessels slightly to increase nutrition for upregulated activity, but not a very large affect

Major affect of PS-ANS on SG secretion

Causes the production of kallikrein from the salivary cells → produces bradykinin, a strong vasodilator (essentially a hormone)

Affect of S-ANS on SG secretion

Slightly upregulates activity

Senses that also regulate SG activity

• Sight

• Smell

• Taste

GIT conditions that will upregulate SG activity

Any sort of irritation (GERD) → soothes GIT and tries to neutralize anything there

Alternative (non-human) functions of saliva

• Defense

• Evaporative cooling

• Constructing nests

• Wound care

Sialocele

Accumulation of fluid in a SG due to a disruption in the secretion/drainage of saliva

Sialocele treatment

• Gland removal

• Marsupialization

• Lancing: short term solution

Causes of hypersalivation (it doesn’t just happen)

• Decreased clearance due to blockage in throat

• Before vomiting in anticipation of the acid

• Organophosphate toxicity

• Brain lesions

• A million other things

Major consequences due to hypersalivation

Transient metabolic acidosis due to the loss of water and bicarbonate