DIGESTIVE SYSTEM

• The Mouth


  The two main functions are eating and speaking. Parts include lips, vestibule, mouth cavity, gums, teeth, hard and soft palate, tongue and salivary glands. Also known as the oral cavity or buccal cavity.
• The Esophagus


  The primary function is to transport food entering the mouth through the throat and into the stomach. This function begins at the upper esophageal sphincter (UES).
• The Stomach

  • Temporarily store food
  • Contract and relax to mix and break down food
  • Produce enzymes and other specialized cells to digest food
• The Intestine


  The main purpose is to digest food. It also produces various substances that carry messages to other parts of the body, and plays an important role in fighting germs and regulating the body's water balance.
• The Small Intestine


  The principal function is to break down food, absorb nutrients needed for the body, and get rid of the unnecessary components. It also plays a role in the immune system, acting as a barrier to a multitude of flora that inhabits the gut and to make sure no harmful bacteria enter the body.
• The Liver


  • The storage location for fat-soluble vitamins and handles cholesterol homeostasis
  • Regulates most chemical levels in the blood and excretes a product called bile to carry away waste products
  • All the blood leaving the stomach and intestines passes through the liver
• The Pancreas

  • Has an exocrine function that helps in digestion by producing enzymes
  • Has an endocrine function that regulates blood sugar by producing the hormone insulin
• The Gallbladder


  Stores bile, a liquid produced by the liver that helps digest fat
• The Large Intestine


  • Absorbs water and electrolytes
  • Produces and absorbs vitamins
  • Forms and propels feces toward the rectum for elimination
• The Anus


  Consists of pelvic floor muscles and two anal sphincters (internal and external) that detect rectal contents and control when stool should and shouldn't be excreted from the body
• RIHANNA, METRAN
• Accessory organs of the digestive system

  Organs that work along with the gastrointestinal tract as part of the digestive system, but are not part of the gastrointestinal tract itself
• Accessory organs of the digestive system

  • Liver
  • Pancreas
  • Gallbladder
  • Salivary glands
• Liver


  • Largest gland in the body
  • Accessory organ of the digestive system
• Liver location

  Located primarily in the right hypochondriac and epigastric regions of the abdomen, just beneath the diaphragm
• Liver

  • Divided into two major lobes and two smaller lobes
  • Functional units are lobules with sinusoids that carry blood from the periphery to the central vein of the lobule
• Liver


  • Reddish-brown, wedge-shaped structure
  • Normally weighs about 1.5 kg (3.3 lb) in adults
  • Largest internal organ and largest gland in the human body
• Liver blood supply

  Connected to two large blood vessels: the hepatic artery (carries oxygen-rich blood from the aorta) and the portal vein (carries blood rich in digested nutrients from the GI tract and wastes filtered from the blood by the spleen)
• Liver functions

  • Secretion
  • Synthesis of bile salts
  • Synthesis of plasma protein
  • Storage
  • Detoxification
  • Excretion
  • Carbohydrate metabolism
  • Lipid metabolism
  • Protein metabolism
  • Filtering
• Bile


  Yellowish alkaline liquid produced by the liver, consisting of water, electrolytes, bile salts, and cholesterol, among other substances, many of which are waste products
• Bile production and secretion

  1. Bile is secreted into small ducts that join together to form larger ducts, with just one large duct carrying bile out of the liver

  2. If bile is needed to digest a meal, it goes directly to the duodenum through the common bile duct

  3. Bile that is secreted when digestion is not taking place goes to the gallbladder for storage until the next meal
• Gallbladder


  A pear-shaped sac attached to the visceral surface of the liver by the cystic duct, that serves as a storage reservoir for bile
• Gallbladder


  • Small, hollow, pouch-like organ that lies just under the right side of the liver
  • About 8 cm (3.1 in.) long and shaped like a tapered sac, with the open end continuous with the cystic duct
• Gallbladder function

  1. Stores and concentrates bile from the liver until it is needed in the duodenum to help digest lipids

  2. A hormone stimulated by the presence of fat in the duodenum signals the gallbladder to contract and force its contents back through the cystic duct and into the common bile duct to drain into the duodenum
• Bile salts


  Act as emulsifying agents in the digestion and absorption of fats
• Pancreas


  A glandular organ that is part of both the digestive system and the endocrine system, located in the abdomen behind the stomach
• Pancreas


  • About 15 cm (6 in.) long, with two major ducts: the main pancreatic duct and the accessory pancreatic duct, both of which drain into the duodenum
• Endocrine function of the pancreas

  Secretes hormones like insulin and glucagon into the blood
• Exocrine function of the pancreas

  Secretes digestive enzymes like amylase, trypsin, peptidase, and lipase into the pancreatic ducts, which drain into the duodenum
• Pancreatic secretion


  Stimulated by the presence of food in the stomach and duodenum, which triggers the release of endocrine hormones that reach the pancreas via the bloodstream
• Digestive system


  Complex network of organs and tissues responsible for processing food, extracting nutrients, and eliminating waste from the body
• Digestive system


  • Its primary function is to break down ingested food into smaller molecules that can be absorbed into the bloodstream and utilized by the body for energy, growth, and repair
• Main parts of the human digestive system

  • Mouth
  • Pharynx (throat)
  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine (colon)
  • Rectum
  • Anus
• Function of the digestive system

  To digest and absorb food and then excrete the waste products
• Mechanical digestion in the mouth

  1. Chewing (mastication)

  2. Mixing with saliva
• Saliva


  Contains water, electrolytes, mucus, and enzymes (e.g., amylase, lipase) that help initiate the digestion process
• Amylase


  Breaks down starches into maltose, a disaccharide, which is further broken down by enzymes in the small intestine into glucose for absorption
• Importance of saliva

  • Lubricates food, making it easier to swallow and facilitating its movement through the digestive tract
  • Initiates the digestion process
• Esophagus

  Muscular tube approximately 25-30 centimeters long that connects the throat (pharynx) to the stomach
• Function of the esophagus

  Transporting chewed food (bolus) from the mouth to the stomach through peristalsis