Saliva Secretion and Appetite Appreciation

So what happens when you place a lump of that nutritious meal in your mouth? Your salivary gland that secret saliva serves to prepare your mouth for swallowing.
This post would discuss the major functions of the mouth, salivary gland as well as the appreciation of taste.

THE MOUTH
Apart from clinical practices, the mouth remains the means whereby food is channeled to where they will be absorbed into the body. As earlier pointed, the alimentary canal is a tube of 30feet length. It is regarded s a tube because of the opening at both ends.
The mouth may otherwise be called buccal cavity. It encloses the teeth, tongue and salivary gland. Opening one end to the lips and the other end to the pharynx.
Major functions of the mouth include
#1 Ingestion of food materials, chewing and mix of ingested with saliva
#2 Appreciation of taste
#3 Formation of bolus (for swallowing).
#4 It is also assist in speech, and other social function.

SALIVARY GLANDS
Basically, the mouth region is lined with various duct through which saliva pass through before releasing their content in the mouth.
The salivary glands include:
#1 Parotid glands: found at the side of the face just below and in front of the ear. Its secretion is emptied into the oral cavity by Stensen duct measuring about 35mm-40mm long opening inside the check against the upper second molar tooth.
#2 Submaxillary glands: found in submaxillary triangle, medial to mandible. It empties its content into the oral cavity by Wharton duct which is about 40mm long. The duct opens at the side of frenulum of tongue by small opening in the summit of papilla called carniculla sublingualis.
#3 Sublingual gland: situated in the mucosa at the floor of the mouth. About 5 to 15 small ducts called ducts of Ravines receive this gland content. These ducts open on small papillae beneath the tongue.
Other salivary glands includes (i) Lingual mucus glands found in posterior one third of the tongue at the tip and margins of tongue behind circumvallated papillae
(ii) Lingual serous glands located near circumvallated papillae and filiform papilla
(iii) Buccal glands present between the mucus membrane around the orifice of mouth
(iv) palatal glands found beneath the mucus membrane of the soft palate.

One will notice that in the course of swallowing or splitting out, the saliva could get a lot thicker (mucus) or thinner (serous) or sometimes mixed, lets outline those gland responsible.
Serous gland: made up of serous cells. They secrete thin and watery saliva. Serous glands are parotid glands and lingual serous glands.
Mucus glands: mainly made up of mucus cells. They secrete thick, viscous saliva with high mucin content. Lingual mucus glands and buccal glands and palatal glands are the mucous glands.
Mixed glands: made up of both serous and mucus cells, submandibular, sublingual and labial glands are the mixed glands.

The duct system of the salivary glands is called Racemose type (because of its grapelike appearance). The salivary glands are formed by acini or alveoli with a central cavity that is continuous with the lumen of the duct. They drain into intercalated duct and join together to form intralobular duct. Where few intralobular ducts join, they form interlobular ducts where they unite to form the main glands.

FACTS ABOUT SALIVA
#1. An average of 1000ml to 1500ml of saliva is secreted per day with a slightly acidic pH of 6.35 to 6.85
#2. Mixed saliva contains 99.5% water and 0.5% solids
#3. The parotid gland contributes 25%, submaxillary glands 70% and sublingual gland 5% of total salivary volume.
Substances found in saliva includes mucin, albumin, maltase, lysosome, etc. normally, glucose is not found in the saliva. The presence of glucose is an indication of the presence of a disease.

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Let’s Talk About the Stomach The Stomach The stomach is a hallow organ that is just below the diaphragm on the left side of the abdominal cavity.  It is a thick walled organ that lies between the esophagus and the proximal part of the small intestine (the duodenum). The stomach has four parts namely the Cardiac region, fundus, body and the pyloric region. Do you know that an empty stomach is 50ml and can accommodate 1L to 1.5L of solids and liquids. A mucus membrane lines the stomach which contains glands (with chief cells) that secrete gastric juice, up to three quarts of this digestive fluid is produced daily. The gastric glands begin secreting due to the parasympathetic impulses of the vagus nerve even before food enters into it. What causes that rumbling when you perceive that delicious food: The secretion of gastric juices from the gastric glands occurs in three phases: cephalic, gastric and intestinal secretion. The cephalic phase is activated by the smell and taste of food and swallowing while the gastric phase is activate by the chemical effects of food and the distention of the stomach. Also the intestinal phase blocks the effect of the cephalic and gastric phases. Another important feature of the gastric juice is the pepsin which primarily digest proteins, hydrochloric acid and mucus. The hydrochloric acid causes the stomach to maintain pH of about 2 which helps kill bacteria that may be present in the food. On the inside of the stomach there are folds of the skin called the gastric rugae. It becomes distended (extends) especially after a very big meal.
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Courtesy organsofthebody.com

Parts of the Stomach The stomach is divided into four sections with individual functions. They include: (I) The cardiac region, the point where the esophagus content is emptied into the stomach. (II) Fundus, formed by the layer curvature of the organ. It is elevated above the level of esophageal opening. (III) Body: the largest part of stomach (about 75% to 80%) of the whole stomach. It extends from just below the fundus up to the pyloric region (IV) Pylorus or atrium, the lower section of the organ that facilities emptying the contents into the small intestine. Sphincters of the Stomach There are two sphincters that keep the contents of the stomach intact namely (I) cardiac or esophageal sphincter, dividing the tract above (ii) pyloric sphincter, dividing the stomach from the small intestine. Don't forget to share