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11 Cards in this Set
- Front
- Back
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What glands produce saliva?
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Make 1.5 L/day (majority while eating)
Parotid Glands - 25% - secrete serous saliva Submaxillary Glands - 70% - secrete mixed serous/mucus fluid Sublingual Glands - 5% - secrete mucus saliva |
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What comes out of these glands?
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Mucins - for lubrication
Electrolytes Salivary alpha-amylase (the same amylase for starch digestion that comes out of the pancreas. R-proteins - bind to Vit B12 in mouth Lipases from VonEbner's gland Lingual Lipase - for lipid hydrolysis (important in babies b/c of ^ fat diet.) (LL less important in humans b/c of pancreatic lipases that are so effective) |
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What binds vit B12 in the saliva and why so early in the GI tract?
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Vit B12 is an essential vitamin for maturation of RBC's, without it you can get Pernicious Anemia. So u need to protect it until it gets to the SI. In the stomach is also binds to IF, creating a R/B12/IF complex.
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What type of cells secrete saliva?
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acinar cells - primary secretion is coming from cells and this fluid is coming from the blood. The blood flow to glands is very important. Increasing BF to salvitory glands, increases there ability to produce secretions. Even at high secretory rates the saliva is hypotonic compared to the plasma.
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Explain PNS innervation to the salivary glands?
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PNS dilates vessels and increases BF to these glands. This then increases ultrafiltrate traveling through the acinar cells into the lumen of the acinus. (ultrafiltrate is the serous component of plasma containing electrolytes, it does not include proteins, RBCs, or big molecultes)
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What is the primary secretion of the acinar cells made up of?
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-Ultrafiltrate from blood
-Mucin from mucin droplets -Zymogen Granules - containing alpha-amylase |
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What happens to flow rate as the primary secretion of these cells goes through the glandular ducts?
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The rate of flow through these ducts dictates composition. If flow is slower then more absorption takes place and the secretion will be less concentrated. So the flow rate dictates the final composition of the fluid.
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What controls salivary flow?
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PNS, SNS, and central control.
PNS! And it's not through the Vagus n., but through the Glossopharyngeal n. (CN IX) and the Facial n. (CN VII). If u increase PNS, you increase flow! SNS stops flow! This is b/c of symp innervation of myoepithelial cells that constrict, preventing salivatory flow. If PNS were denervated, salivary glands would atrophy. Central Control - afferent signals are sent to the salivary nucleus at the pons-medulla border and then efferents tell your glands to secrete saliva. |
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What increases salivary flow?
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INCREASES
-PNS -CNS -Nausea -Esophogeal Distention -Food DECREASES -SNS -NE -Hormones: ADH and Aldosterone (conservation of salt and fluid in ducts) -Sleep -Dehydration -Drugs (Chemo) -Aging (decrease in autonomic tone and glands atrophy) |
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What are the functions of saliva?
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1. Taste - because of it's role in the initial breakdown of starch and fats
2. Protection - has antimicrobial action, WBC, coagulation factors (IgA's) (why dogs lick wounds) 3. Digestion - Enzymes 4. Lubrication - mucin 5. Oral Hygiene - by swallowing and spitting u reduce bacteria. People who have low salivation have an increased risk of cavities. |
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Important points about saliva...
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1.5 L/day
High in K (20 meq/L) compared to plasma (4 mEq/L) Always hypotonic to plasma at any secretory rate! Acidic, pH=6, possibly due to KCL |
