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Digestive System, Cassidy Zuniga, P:6 - Coggle Diagram

- - - - Peristalsis- propulsion by contraction and relaxation of smooth muscles lining the alimentary canal
    - - Mechanical- physical breakdown of food by cutting and grinding
      - Chemical- requires enzymes
- - - - opening into the oral cavity
      - contains teeth, salivary glands, tonsils, and tongue
      - mixing of food with saliva by the tongue to make bolus (ball of food)
      - mucosa provides mucus to coat bolus for easier transport
      - initiates of deglutition (swallowing)
      - tongue allows for sense of taste
      - immune function by the palatine tonsils
    - - Oropharynx- located posteriorly to mouth, passage for food, water, and air
      - Laryngopharynx- inferior to oropharynx
      - involved in deglutition, forcing bolus from the mouth to esophagus
    - - collapsible tube runs from the pharynx to stomach, pass through diaphragm
      - located posteriorly to the trachea
      - food transported by peristalsis
      - no digestive function, only passage for food and water
    - - located left of the abdominal cavity in left hydrochondric region
      - food enters at the cardio esophageal sphincter (prevents food r stomach acid enter esophagus)
      - Rugae - intenal folds of stomach mucosa
      - food empties into duodenum of small intestine at the pyloric sphincter
      - j-shaped, acts as storage tank for food
      - food mixes with gastric juice to make chyme
  - - - muscular tube extending from the pyloric sphincter to the ileocecal vaive
      - peristalsis and segmental movement mix chyme with digestive enzymes
      - Regions
        
        Duodenum- first portion of SI attached to stomach, chemical digestion
        
        Jejunum- middle section, main site of nutrient absorption
        
        Ileum- end portion, connected to cecum, some absorption
        
        Villi of SI- fingerlike structures that increase surface area for absorption
    - - eliminates indigestible food from body as feces
      - does not participate in digestion but resident bacteria digest remaining nutrients: causes gas or flatulation (farts)
      - Regions
        
        Cecum- first outpocketing of the LI; attached to small intestine; site of appendix attachment
        
        Colon- ascending, transverse, descending, and sigmoid colon
        
        Colon- stores feces until it is defecated
      - Features
        
        contains tenia coli (longitudinal muscles)
        
        Haustria- bulges or pockets along LI
      - Movement is sow and sluggish in the LI except for 3-4 mass persistaltic movement per day toward rectum
    - - eliminates feces from rectum to exterior
      - defecation controlled
        by sphincters
        
        Internal- made of involuntary smooth muscle
        
        External- voluntary skeletal muscle
      - presence of feces in rectum triggers defecation reflex
  - - - produces saliva (mixture of 99% water and mucus) to moistens food into bolus
      - contains salivary amylase: digest starch
      - 3 pairs of glands: parotid submandibular, and sublingual
    - - hardest substance in the body, functions to mechanically break down food into smaller pieces
      - Anatomy
        
        Enamel- hard outer layer of teeth
        
        Dentin- middle layer of bone-like living tissue under enamel
        
        Pulp- softer inner structure: contains nerves and blood vessel
        
        Supporting Ligament- connective tissue that attaches teeth to jawbone
        
        Gingivi- gums
      - Regions
        
        Crown- part of tooth above the gums
        
        Root- anchored under gums
      - Types
        
        Deciduous- baby teeth (20)
        
        Permanent- adult teeth (32)
        
        Incisors- most anterior, for cutting
        
        Cuspids or Canines- lateral to incisors; for tearing/shredding
        
        Premolars & Molars- sides and back teeth; grinding
    - - Goblet Cells - produce mucus (provide protective lining against stomach acid)
      - Chief cells - produces pepsinogen
        
        Pepsinogen, in presence of hydrochloric acid (HCI), converts pepsinogen to pepsin
        
        Pepsin - protein digesting enzyme in stomach
      - Parietal Cells - produces HCI
        and intrinsic factor
        
        intrinsic factor - needed for absorption of vitamin B12 in stomach
    - - pear-shaped organ: located on the underside of liver on the right side of abdominal cavity (right hypochondriac region)
      - stores bile and released into duodenum when needed
    - - largest gland in body: made of 4 lobes
      - located inferior to diaphragm
      - falciform ligament holds lobes to abdominal walls
      - functions for storage for glycogen, fat soluble vitamins, and iron
      - produces bile (emulsifies fat)
      - removal of drugs, alcohol, and hormone
    - - Secrete intestinal juice (mixture of fluids)
      - Duodenal glands - alkaline mucus
        to neutralize stomach acid
        
        Enzymes in duodenum digest all food groups but requires neutral pH to work
    - - located behind stomach surrounded by duodenum
      - produces digestive enzymes
      - releases enzymes into duodenum
      - regulates blood sugar by producing insulin
- - - - produces mucus for reduction of friction and protections
      - epithelium; nonkeratinized stratified squamous in mouth, esophagus, and anus, protection against friction
      - lamina propria; contains blood and lymphatic vessels, and lymph node for nourishment and immunity
      - muscularis mucosae; two thin layers of smooth muscles
    - - areolar connective tissue containing major blood vessel
      - many elastic fibers to retain shape
      - submucosal plexus; autonomic nerve supply
      - glands and lymphatic tissue
    - - two layers of smooth muscles to
        allow peristalsis and segmentation
        
        Inner Circular Layer- squeeze, decrease size of lumen; in some areas act as sphincter or values
        
        Outer Longitudinal Layer- shortens intestine
      - mouth, pharynx, superior esophagus, and anal sphincter - voluntary muscle
      - also external anal sphincter is skeletal muscle
    - - outer covering of the GI tract
      - serous membrane - composed of thin layer of areolar connective tissue and simple squamous epithelium
      - produces serous fluid for lubrication