SCIENCE

• Sublingual glands – are the glands that are situated under the tongue.
• 800-100 minor salivary glands – labial, buccal, glossopalatine, palatine and lingual glands
• Normal pH range – 6.2 to 7.6 (Saliva)
• Ptyalin or Salivary amylase – (Saliva) enzyme which partially digests the starch content of the food and breaks it down into maltose and dextrin
• Teeth – are located in different positions and perform different functions.
• Incisors & Canine – are used for tearing and biting food.
• Premolars & Molars – are ideal for chewing because they have large surfaces
• Adult : 32 teeth
• Children : 20 primary teeth
• Bolus – starchy ball of food (converted by enzymes) | rounded soft mass of chewed food
• Soft palate – help push the food down to the pharynx and esophagus
• Papillae – (rough surfaces) contain the taste buds
• Taste receptors – (Nerves) that help detect different tastes and send taste signals to the brain
• 5 basic taste sensations: sweet, sour, salty, bitter, and umami or savory taste.
• Capsaicin – component in spice
• Pharynx (throat) – connects the mouth to the esophagus.
• Esophagus – passes through when the food is swallowed. It is a muscular tube that is approximately 25 cm long. When food has reached it, it is pushed down further into the stomach through peristalsis
• Peristalsis – is the series of involuntary, wavelike muscular contractions that usually occurs in the digestive tract.
• Mucus – is a sticky substance that aids the food bolus to be pushed down.
• Lower esophageal sphincter (LES) / muscular valve – relaxes and allows the food to pass into the stomach.
• Stomach – is a muscular, expandable organ located on the left side of the upper abdomen.
• Inner lining of the stomach – has glands that secrete gastric juices and mucus that help enhance the digestion process.
• Gastric juice – is composed of hydrochloric acid (HCI) and a digestive enzyme called pepsin
• Hydrochloric acid – is a strong acid that has a pH level between 1 and 2
• Rugae – ridges of muscles tissue that helps expand the surface area of the stomach
• Mechanical digestion – muscles in the stomach walls churn, which allows it to be mixed with the gastric juice and digestive enzymes (chemical digestion)
• Chyme – thick, semi-liquid food mass
• Pyloric sphincter – muscular valve of the small intestine
• Small intestine – is about six to seven meters (m) long and about two to four cm wide
• Three segments of small intestine:

  1.      Duodenum

  2.      Jejunum

  3.      Ileum
• Duodenum – first segment of the small intestine; mainly for digestion and neutralization of the chyme’s acidity.
•       Jejunum –  primarily absorbs sugars, amino acids, and fatty acids
• Ileum – absorbs Vitamin B12, bile salts, and other nutrients
• Pancreas – is a long, narrow gland that stretches from the spleen to about halfway through the duodenum.
• Pancreatic juice –breaks down proteins, fats, and carbohydrates. It is a mixture of water, digestive enzymes, bicarbonates, and electrolytes.
• Three enzymes in the pancreatic juice that play important function

  1. Trypsin (Proteolytic enzyme/proteinase)

  2. Lipase

  3. Pancreatic amylase
• Trypsin (Proteolytic enzyme/proteinase) – is an active enzyme that digests the proteins from the food.
• Lipase (enzyme) – helps the body absorb fats
• Pancreatic amylase – changes starch and glycogen into maltose, a disaccharide
• Peptidases – further break down the peptides into single amino acids