1. Histology of Digestive Tract
   1. 4 layers
      1. Mucosa
         1. innermost tunic; 3 separate layers
            1. mucous epithelium
            2. lamina properia
            3. muscularis mucosa
      2. submucosa
         1. beneath the mucosa
            1. contains nerves, blood vessels, lymphatic vessels, and small glands
      3. muscularis
         1. muscular layer
            1. inner layer of circular smooth muscle
            2. outer layer of longitudinal smooth muscle
      4. Serosa or Adventitia
         1. Parts of DT located within the peritoneal cavity have serosa as outermost layer (visceral peratoneum)
            1. visceral perotenium: thin layer of connective tissue and simple squamous epithelium
         2. When he outer layer of DT derived from adjacent connective tissue connective tissue, it is called adventitia
2. Peritoneum
   1. walls and organs of abdominal cavity are lined with continuous serous membrane (peritoneum)
      1. very smooth and secrete serous fluid; provides lubrication and it reduce friction
         1. visceral peritoneum: merges with portion that covers interior surface of the wall of abdominal called parital peritoneum
         2. parietal peritoneum: serous membrane also surround other organs of the body
   2. all digestive organs within abdominal cavity are held in place by structure called mesentary
      1. mesenteries are continuous, double layer of epithelial tissue
3. lips, cheeks, and palates
   1. lips and cheeks are important in mastication and speech
      1. manipulate food and hold it in place along oral cavity
         1. lips (labia)
            1. form interior boundary of vestibule
            2. each lip has a central mucosal fold called labial frenulum
         2. cheeks
            1. lateral wall of oral cavity
         3. palate
            1. roof of oral cavity
            2. soft palate
            3. posterior non-bony part
            4. consists of skeletal muscle and connective tissue
            5. hard palate
            6. anterior bony part
         4. uvula
            1. posteior projection from soft palate
         5. fauces
            1. posterior boundary of oral cavity
4. tongue
   1. large muscular organ that occupies most of the oral cavity proper when mouth is closed
      1. a groove called terminal sulcus divides tongue into two parts
         1. body
            1. found within the oral cavity and is relatively free, except for the floor of mouth which the labial frenulum holds it in place
         2. root
            1. within the oropharynx and contains a few scattered taste buds and the lingual tonsils
   2. muscles of the tongue
      1. intirinsic muscles
         1. wintin tongue itself
         2. largely responsible for changing shape of tongue
      2. extrinsic muscle
         1. protude and retract the tongue, move it from side to side, and change shape
         2. outside of tongue but are attached to it
   3. importance of tongue
      1. moves food in the mouth and holds food in place of mastication
      2. major role in swallowing
      3. location of taste buds
      4. primary organs of speech
5. teeth (dentition)
   1. funtions of teeth
      1. masticate
      2. assists in speech
   2. Adults usually have 32 teeth
      1. 20 + 12 (molars)
   3. 4 quadrants
      1. right upper
      2. left upper
      3. right lower
      4. left lower
   4. types of teeth
      1. incosors
         1. front (cutting)
      2. canine
         1. pointed and sharp (tearing)
      3. premolar
         1. transition of canine to molar
      4. molar
         1. grinding teeth
   5. Tooth structure
      1. crown
         1. part of the tooth that is exposed; covered by enamel
      2. neck
         1. small region between crown and root
      3. root
         1. largest regon of tooth
         2. anchors the tooth in the bone
6. Salivary Gland
   1. three pairs
      1. parotid (largest)
         1. anterior to ear
      2. Submandibular (Most)
         1. beneath mandible
      3. Sublingual (smallest)
         1. beneath tongue
   2. saliva makes ions and immunoglobulins A, mucin (lubricant, salivary amylase
      1. mucin
         1. takes something dry, make it wet for easier travel through DT
      2. salivary amylase
         1. breakdown of sugar and carbohydrate
7. pharynx
   1. oropharynx
   2. laryngopharynx
8. Esophagus
   1. transport food from pharynx to stomach
   2. passes into abdominal cavity through esophageal hiatus of diaphram
   3. anterior of vertebral column
   4. deglutition: process of swallowing
      1. initiation phase
         1. movement of tongue
         2. voluntary
      2. pharangeal phase
         1. involuntary
         2. skeletal!!
         3. superior, medial, and inferior
      3. esophegial phase
         1. involuntary
         2. involves smooth muscles!!!
9. Functions of Digestive System
   1. Ingestion
      1. intake of solid and liquid
         1. mastication (chewing) to begin process of digestion
   2. Propulsion
      1. movement of material from end end of DT to the other
         1. Swallowing: bolus from teh oral cavity into esophagus
         2. Perastalsis: propels food through digestive tract
   3. Secretion
      1. lubrication; easier for food to go down the DT
         1. Mucus: coats and protects DT from abrasion, stomach acid, and digestive enzyme
         2. Secretion contains large amount of water
         3. Enzymes secreted break down large food into smaller can be absorbed by intestinal wall
   4. Digestion
      1. breakdown of larger food into their individual component
         1. mechanical digestion: involves mastication and mixing of food
         2. chemical digestion: digestive enzyme secreted along DT
   5. Absorption
      1. Movement of molecules out of DT into blood or into lymphatic system
         1. nutrients are taken
   6. Elimination of Waste
      1. waste products of digestion are removed from the body
         1. feces are stored and then dumped (defacation)
10. order of the food travels
    1. Digestive tract (DT)
       1. mouth
       2. pharynx
       3. esophagus
       4. stomach
       5. Small intestine
       6. Large intestine
    2. Accessory Organs
       1. teeth
       2. tongue
       3. salivary gland
       4. liver
       5. pancreas
       6. gallbladder
11. stomach
    1. Openings
       1. cardiac sphincter (gastroesophageal)
       2. pyloric sphincter
          1. sphincter going out
    2. regions (4)
       1. Cardiac
       2. Fundus
       3. body
       4. Pyloric
    3. Bolus enter stomach and turns into chyme by acid
    4. histology of Stomach
       1. serosa (visceral peritoneum)
          1. outermost tunic of stomach
          2. consists outer layer of squamous epithelium and inner layer of connective tissue
       2. Muscularis
          1. outer longitudinal
          2. middle circular
          3. inner oblique
             1. generate strong stomach contractions that physically break down ingested food into smaller pieces
       3. Submucosa
       4. Mucosa
12. Small Intestine
    1. primary role in the inegestion and absorption of nutrients(90%)
    2. 3 subdivisions
       1. Duodenum
          1. mixing bowl
          2. region connected to stomach
       2. jejunum
          1. site of most chemical digestion and absorption
       3. ileum
          1. right before going to Large intestine
    3. Transverse folds (plicae circulares) and small progections (intestinal villi) increae surface area for absorption
    4. Intestinal juices moistens chyme, help buffer acid, and holds enzyme and products of digestion in solution
13. Liver
    1. Lobes
       1. Major
          1. left
          2. right
             1. bigger lobe
       2. Minor
          1. Caudate
             1. associated with the inferior vena cava
          2. Quadrate
             1. associated with gallbladder
    2. round ligament separates the lobes
    3. functions of liver
       1. produce digestive enzyme (bile)
14. Ducts
    1. Left and right hepatic ducts
       1. drains out each of the lobe
    2. common hepatic duct
       1. merging/combining of the two lobe
    3. cystic duct
       1. drains out the gallbladder
    4. common bile duct
       1. drains out both common hepatic (liver) and cu=ystic duct (gallbladder)
    5. main pancreatic duct
       1. dijestice juices from the pancreas
    6. hepatopancreatic ampulla
       1. digestive juices from gallbladder, liver, pancreas
    7. Major duodenal papialla
       1. opening
       2. get mixed up and slide it to small intestine
15. Pancreas
    1. regions
       1. head
          1. closest to duodenum
       2. body
       3. tail
    2. Both an endocrine and exocrine gland
       1. endocrine
          1. Pancreatic islets produce glucegon and insulin
       2. exocrine
          1. acini produce digestive enzyme
    3. behind stomach by the spleen
16. Large intestine (aka colon)
    1. 4 portions
       1. ascending
       2. transverse
       3. descending
       4. sigmoid
          1. S- shape
    2. Rt and Lt colic flexures divides portion
       1. Rt colic flexure is also known as hepatic flexure
       2. Lt colic flexure is also known as spleenic flexure
    3. haustra and tenia coli assist with movement and absorption of bolus
       1. haustra - little bubbles
       2. tenia coli- cord-like structure along the LI; continue parystalsis
17. frenulum: a cord-like structure that connects lips and tongue to tissue of the mouth
18. vestibule: space between cheek and teeth
19. oral cavity proper: space between teeth
20. within center of tooth, in neck and root, is pulp cavity/chamber (where nerve and blood supply)
21. each quadrant has one central and one lateral incisor; one canine; first and second premolar; and first, second, and third molar (third molar wisdom teeth)
22. difference between pharangeal and esophegial