Digestive

• Function of Digestive System

  • Ingestion - Taking of food
  • Mastication - Chewing of food
  • Digestion - Breaking down of food
  • Mechanical / Physical Digestion - Physical breaking of food froma big piece to small pieces
  • Chemical / Enzymatic Digestion - Converting the food into simplesubstance that can be absorbed and utilized by the body
• Function of Digestive System

  • Absorption - Food into the bloodstream
  • Circulation - Food distribution
  • Assimilation - Incorporation of food into the body tissues and cells
  • Defecation / Egestion - Dumping waste products
• Accessory Parts

  • Oral Cavity
  • Aid in the process of digestion
• Oral Cavity

  Mouth - Entrance of food

  Uvula - Prevents the entry of food into the nasal cavity
• Oral Cavity

  Palate

  Hard Palate: Provides a surface for chewing and separates the mouth from the nasal cavity

  Soft Palate: Closes off the nasal passages during swallowing and helps produce certain sounds during speech.
• Oral Cavity

  Lips

  Upper Lip: Helps in speech articulation and facial expression.

  Lower Lip: Assists in speech articulation, holds food during eating, and protects the teeth and gums.
• Oral Cavity

  Pharynx

  • Nasopharynx: connects the nasal cavity to the rest of the pharynx, allowing air passage during breathing and acting as a resonating chamber for speech sounds.
  • Oropharynx: connects the mouth to the rest of the pharynx, playing a role in swallowing and breathing, and serving as a pathway for air and food.
  • Laryngopharynx: connects the larynx to the esophagus, playing a role in both swallowing and breathing.
• Oral Cavity

  Tongue: Holds & directs the food

  • Attachment: Frenulum

  
• Tooth Anatomy

  A) Crown

  B) Neck

  C) Root

  
• Tooth Anatomy

  A) Dentin

  B) Enamel

  C) Pulp Cavity

  D) Cementum

  
• Digestive Glands

  • Secrete substances
  • For the process of digestion
• Liver - Produces bile
• Gallbladder - Stores bile
• Bile - Fat emulsification
• Salivary Glands - Moisten and soften the food

  • Helps in chewing & swallowing
  • Aids in digestion -> Amylase (Polysaccharide digestion)
  • Contains antibodies that kill germs
• Submandibular gland - inner to mandible
• Parotid gland - anterior to the ear
• Sublingual gland - below the tongue
• Pancreas

  • Pancreatic Juice -> Pancreatic Amylase (Starch digestion)
  • Trypsin Chymotrypsin Carboxypeptidase (Protein digestion)
  • Lipase (Fat digestion)
• Gastric Gland

  Gastric Juice: Hydrochloric Acid - kills bacteria, activates pepsinogen

  Pepsin - protein digestion

  Mucin - protects gastric wall
• Intestinal Gland

  Intestinal Juice:

  • Protease -> proteins
  • Lipase -> fats / lipids
  • Amylase -> carbohydrates
• Digestive Tract - Passages of food

  For the various processes
• Digestive Tract

  Stomach (Partial digestion) - Temporary storage of food

  Esophagus - Passage of food from the oral cavity to the stomach

  Gastroesophageal sphincter - prevents stomach contents from flowing back into the esophagus.
• Digestive Tract

  Small Intestine - Final digestion & absorption of food; 20 ft. long

  1. Duodenum: 1st & shortest region (20cm - 25 cm long)
  2. Jejunum: 2nd region (2.5m long)
  3. Ileum: last coiled region (3m long)
• Large Intestine - Reabsorption of water and mineral ions (sodium & chloride)

  • Formation & temporary storage of feces
• 4 Regions of Large Intestine

  A) ascending colon

  B) descending colon

  C) transverse colon

  D) sigmoid colon

  
• Other Parts of the Large Intestine

  Cecum - Pouch at the junction of the small & large intestines

  • Receives undigested food

  Appendix: Immune system

  Rectum: Temporary storage of feces

  Anus: Posterior Opening
• Digestion