Science

• The primary purpose of the digestive system is to break down food to facilitate the effective transport of nutrients to different parts of the body.
• The digestive tract, also known as the alimentary canal or gastrointestinal tract, consists of nine major parts: the mouth, esophagus, stomach, pancreas, liver, small intestine, large intestine, rectum, and anus
• Mechanical breakdown of food happens in the mouth, where teeth grind food into smaller pieces.
• Carbohydrates are digested by enzymes in saliva.
• Mastication, or chewing or grinding of food into smaller pieces, is a crucial part of the digestive process.
• Incisor and Canine teeth bite and tear down food.
• Molar teeth grind food.
• The tongue moves food around while chewing.
• Saliva, produced by salivary glands, contains three types: Buccal, submandibular, and parotid.
• Saliva contains salivary amylase, an enzyme to digest starch and convert it into maltose (sugar).
• The pharynx, also known as the throat, is the passageway for food from the mouth to the esophagus.
• The esophagus is the conveyor of the bolus from the pharynx to the stomach.
• Peristalsis is the process that moves the bolus through the digestive system.
• The stomach is an enlarged saclike portion of the digestive tract where peristalsis and churning action crush and mash food.
• The stomach stays for 3-6 hours and secretes gastric juice, which is produced by gastric glands from the stomach lining.
• Gastric juice contains hydrochloric acid, which activates pepsinogen and destroys microorganisms in food.
• Chyme is food that has been thoroughly digested which becomes a semiliquid and is moved to the pylorus, which has a pyloric sphincter, and enters the duodenum, the first part of the small intestine.
• The small intestine, which is 20-30 ft long, has three parts: the duodenum, jejunum, and ileum.
• Villi, which increase surface area for absorption, are located in the intestinal wall of the small intestine.
• The pancreas, located behind the stomach, stores digestive enzymes and is an exocrine and endocrine gland.
• The liver, which contains 13-14% of the body’s blood supply, functions to produce bile, store glycogen, and produce cholesterol.
• The large intestine, also known as the colon, stores undigested food and some water, vitamins, and electrolytes are absorbed.
• The rectum stores feces and holds it until nerves signal the brain to push it out through the anus.
• The anal canal is the endmost part of the digestive tract and is skin-like.
• What is mucin (mucus)


  protects stomach lining from its own acid
• There are 5 cell types of the endocrine purpose of the pancreas, these are: alpha, beta, delta, PP, and epsilon
• The pancreas can be both an exocrine and endocrine gland
• An exocrine gland secretes digestive enzymes that breakdown fats, carbs, proteins, and bicarbonate ions
• An endocrine gland produces the "islets of Langerhans", aka the 5 kinds of cells produced by the pancreas
• Alpha cells produce glucagon which raises blood sugar levels
• Beta cells produce insulin which lowers blood sugar levels
• Delta cells produce somatostatin which inhibits secretion of other hormones
• Delta cells produce somatostatin which inhibits secretion from other islet cells
• Bolus is the ball-like mass of food that goes down through swallowing
• Peristalsis moves the bolus through the digestive system
• In pepsinogens, zymogens transform into pepsins which break down proteins into peptides
• Hydrochloric acids activates pepsinogen and destroys microorganisms in food
• Assimilation is when nutrients are absorbed in the bloodstream
• The large intestine releases mucus which holds together the feces and lubricate food
• Carbohydrates:

  • 3 types: polysaccharides, disaccharides, monosaccharides
  • Polysaccharides: many sugar molecules (glycogen, starch, cellulose)
  • Disaccharides: 2 sugar molecules (lactose, sucrose, maltose)
  • Monosaccharides: 1 sugar molecule (glucose, galactose, fructose)
  • Type 2 Diabetes is caused by processed and refined carbs that strip fiber and vitamins
  • No further digestion of carbs happens as it travels down the stomach because the chemical action of the S.A is neutralized by stomach acid (TRUE)