chapter 24 lecture threes on the mouth and teeth mouth is also called the oral or buccal cavity it has a vestibule that's bounded by the cheeks and lips and internally bounded by the gums and teeth and the falces is the opening between the oral cavity and the pharynx picture showing the mouth the mouth you can see the teeth will look at the different types of teeth in a little bit the gums are called the gingiva and the gingiva is attached to the lips through these frenula so this is the superior labial frenulum down here is an inferior labial frenulum we also have a lingual frenulum that attaches the base of the tongue to the area underneath the um top of the mouth is made of bone makes the hard palate and then covered by soft tissue that makes up the soft palate in the posterior part we have a piece of skin that dangles down called the uvula and then here we have the arches this is the palito glossal arch and this is the palatopharyngeal arch we also have tonsils and posterior portion the palatoglossal muscle goes from the palate to the tongue and it forms that first Arch the palatopharyngeal muscle goes from the palate to the pharyngeal wall and it forms the second Arch we have three kinds of salivary glands the parotid the submandibular and the sublingual glands The major portion of saliva secreted by these the remainder comes from the buccal glands that are the mucous membrane of the mouth and saliva is very important in our ability not just to taste food as we learned before but also to start digestion it chemically is 99.5 percent water and about 0.5 percent solutes there's salts gases organic substances as well as enzymes salivation is entirely under nervous control this shows the three different salivary glands the largest is the parotid gland then we also have a submandibular gland that sits under the mandible and a sublingual gland that sits under the tongue the cells in the salivary gland are found in clusters or acinai and we have different types of cells that we find there so we call these mixed glands because they have both serous and mucous cells serous fluid we know is a watery kind of fluid and mucous is a thicker secretion the parotid gland only contributes even though it's the largest of the glands it only contributes about 25 percent of the secretions the secretions it secretes are serous secretions with salivary amylase which is an enzyme that begins the digestion of starch the submandibular gland contributes 70 of all secretions and has both mucus and serous secretory cells the sublingual gland is dominated by mucus it contributes about um five percent of the secretions so the function of saliva is to wet food can make it easier to swallow to dissolve food because the sense of taste is a chemical it's a chemical sense and we have to dissolve food in order to taste it it provides bicarbonate ions to buffer acidic Foods people that suffer from bulimia which is the binge and Purge disorder who vomit all the time the stomach acid eats away at the enamel and teeth even though the enamel that we have on our teeth is the hardest substance in our body it can easily be eaten Away by constant acid the chemical digestion the starch is going to start with the salivary amylase and we also produce lysozyme which is an antibacterial enzyme and we'll see this again several times in the GI tract lysozyme is is pretty common throughout we produce about one to one and a half quarts a day of saliva and it's important that we do because the saliva helps it constantly rinses our mouth as well and helps to dislodge bacteria people who suffer from chronic dry mouth from different medications they're taking or from smoking or a number of other causes tend to suffer more Dental caries or more dental problems than people who have normal salivary action so saliva is completely controlled by the nervous system the number of things can cause us to produce saliva the sight smell sound memory of food uh tongue stimulation so any anything you're doing with your tongue or moving something around in your mouth is going to start salivation and the signals to begin salivation come from cranial nerve seven and nine um the to when salivation is stopped it has usually has to do with the sympathetic nervous system mumps is a disease that we don't see too much of lately because of the immunization for measles mumps and rubella or the MMR but it produces swelling kind of chipmunk cheeks because it attacks the parotid gland the symptoms would be fever malaise sour throat swelling and also in males it can affect the testicles so it can produce sterility mumps can either be only on one side or you could have it both sides infected it could be bilateral uh as I said we don't see a lot of mumps anymore since there's been a vaccine available since 1967 however with people uh not getting their kids immunized as much as we used to it's making a comeback