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Elderly M, stomach cancer/gallbladder removal/feeding tube in alimentary…

- - - - Ingests
      - Begins mechanical breakdown (chewing)
      - Initiates propulsion (swallowing)
      - Starts digestion (polysaccharides)
    - - Oropharynx then laryngopharynx
        
        Allows passage of foods, fluids, & air
        
        Pharyngeal constrictors encircle wall of pharynx
        
        Major function = propulsion - momentarily inhibits respiration
    - - Runs from laryngopharynx to stomach, conduit of food
      - Collapsed when not involved in food propulsion
      - Gastroesophageal sphincter keeps cardial orifice (entrance to stomach) closed when no food
      - Major function = propulsion - involuntary/controlled by swallowing center in brain stem
        
        Peristalsis (wave-like constriction/relaxation) moves food to stomach
    - - Temp. storage where chem. breakdown of protein begins; converts food to chyme
        
        Stomach can expand from 50mL to 4L (food)
        
        Major Stomach Regions:
        
        Cardia - surrounds cardial orifice
        
        Fundus - dome shaped, beneath diaphragm
        
        Body - midportion
        
        Pyloric Region - continuous w/ duodenum through pyloric valve (sphincter that controls stomach emptying)
        
        Greater Curvature - convex lateral surface
        
        Lesser Curvature - concave medial surface
        
        Greater & Lesser Omentums help attach stomach to surrounding surfaces
        
        Mucosal barrier protects stomach; made of bicarb mucus, epithelial tight junctions, & damaged cells replaced rapidly by stem cells (complete turnover every 3-6 days)
        
        Stomach Processes:
        
        Store food
        
        Peristalsis/propulsion of food to small intestine
        
        Mechanical breakdown food (churning)
        
        Protein digestion
        
        Absoption into blood of some drugs (lipid soluble)
    - - Small Intestine (peritoneal)
        
        Major organ of digestion/absorption
        
        Duodenum - retroperitoneal, connects to stomach
        
        Jejunum - posterior, ~8ft long, middle section
        
        Ileum - posterior, ~12ft long, connects to LI via ileocecal valve
        
        MALT/Peyer's patches in ileum aid in immune protection
        
        Ileocecal valve opens to admit chyme to LI when force of segmentation/motility of ileum increased
        
        Digestive Process in SI
        
        Chyme = partially digested carbs/proteins, undigested fat; mixed with bile/pancreatic juice to raise pH; takes 3-6 hours to absorb all nutrients/most water
        
        Bile/digestive enzymes imported from pancreas/liver; brush border enzymes from SI perform final digestion
        
        Chyme mixed w/ enzymes/bile via segmentation following a meal
        
        Between meals, peristaltic waves move remnants/debris through SI; ~2 hours from duodenum to ileum
        
        Nutrient absoption via huge surface area (tennis court); modifications.
        
        Circular folds - spiral chyme through lumen, increase nutrient absorption
        
        Villi - fingerlike projections with lacteal capillaries for absorption
        
        Microvilli - fuzzy brush border w/ brush border enzymes which aid in final digestion carbs/protein/nucleic acids
      - Large Intestine (peritoneal/retroperitoneal)
        
        Cecum - first part LI
        
        Appendix - part of MALT immune system
        
        Colon, subdivided into:
        
        Ascending - up right side
        
        Transverse - across abdominal cavity
        
        Descending - down left side abdominal cavity
        
        Sigmoid - S shaped, travels through pelvis
        
        Rectum - 3 rectal valves prevent feces passing w/ gas
        
        Anal canal - final segment LI, w/ internal sphincter (smooth muscle/involuntary) & external sphincter (skeletal muscle/voluntary)
        
        LI = thick mucosa (simple columnar epithelium); abundant deep crypts with mucus-producing goblet cells
        
        Bacterial flora in LI enter from SI or anus to colonize w/ beneficial bacteria/suppress pathogenic bacteria
        
        Fermentation of indigestible carbs/mucin results in flatus
        
        Synthesizes B complex/some vitamin K needed by liver to produce clotting factors
        
        Major function of LI = propulsion of feces to anus & defecation
        
        Residue remains in LI 12-24 hours
        
        No digestion occurs except what enteric bacteria digest
        
        Absorbs vitamins made by bacterial flora, most remaining water, & electrolytes (NaCl)
        
        Defecation reflex initiated by mass movements (peristalsis) forcing feces towards rectum
    - - Mucosa - innermost, lines lumen
        
        Functions = secretion, absorption, & protect against infection
        
        Simple columnar epithelium & mucus-secreting cells = pharynx, stomach, small intestines, large intestines
        
        Stratified squamous epithelium = mouth, esophagus, & anus
      - Submucosa - areolar connective tissue
        
        Contains blood/lymphatic vessels
        
        Abundant elastic tissue for shape retention
      - Muscularis - smooth muscle layer
        
        Inner circular muscle layer
        
        Outer longitudinal layers
        
        Sphincters for valves
      - Serosa - outermost, visceral peritoneum
        
        Adventitia in esophagus (holds e. to surrounding structures)
        
        Retroperitoneal organs have both serosa and adventitia
  - - - Primary Dentition - 20 deciduous/baby teeth, 6-24 months to 6-12 years
      - Mastication - chewing to tear/grind food into small fragments
      - Permanent Teeth - 32 deep rooted teeth, 6-12 years for life
      - Classified by shape
        
        Incisors - chisel, cutting
        
        Canines - fang, tear/pierce
        
        Premolars - broad crowns/rounded cusps, grind/crush
        
        Molars - broad crowns/rounded cusps, best grinders
    - - Bundles skeletal muscle
      - Gripping, repositioning, mixing food while chewing
        
        Creates bolus (mix food/saliva)
      - Initiates swallowing - deglutition
      - Provides sense of taste
    - - Stores/concentrates bile by absorbing water/ions
      - Honeycomb folds allow it to expand as it fills
      - Muscular contractions release bile
        
        Bile released through major duodenal papilla into duodenum (SI)
    - - Digestive function - production of bile
        
        Bile transported via common hepatic duct, which unites w/ cystic duct from gallbladder to form bile duct
      - Largest gland in body (3lb) w/ 4 lobes
        
        Liver cells = hepatocytes, produce ~900mL bile daily
        
        Bile functions in fat emulsification & absorption
    - - Exocrine function = secrete pancreatic juice (digestive enzymes)
        
        Pancreatic Enzymes = proteases (proteins); amylases (carbs); lipases (lipids); nucleases (nucleic acids)
      - Endocrine function = secrete insulin/glucagon via pancreatic islet cells
    - - Salivary Glands
        
        Minor Salivary Glands - in oral cavity
        
        Keep mouth moist
        
        Major Salivary Glands - outside oral cavity
        
        Consists of parotid, submandibular, & sublingual
        
        Produce most saliva
        
        Saliva is 97-99.5% water, includes enzyme amylase
        
        Cleans mouth
        
        Dissolves food chemicals
        
        Moistens food for compaction
        
        Begins starch breakdown (amylase)
        
        Two types secretory cells
        
        Serous - produce watery secretion/enzymes/ions
        
        Mucus - produce mucus to lubricate oral cavity/food
      - Gastric Glands
        
        Produce gastric juice (digestion)
        
        Gastric Gland Cells:
        
        Parietal Cells; secretes
        
        HCl - denatures protein, activates pepsin, breaks down plant cell walls, kills bacteria
        
        Intrinsic Factor - needed for B12 absorption in small intestine; essential for life
        
        Lack of intrinsic factor = pernicious anemia
        
        Chief Cells; secretes
        
        Pepsinogen, activated to pepsin by HCl & pepsin (positive feedback)
        
        Enteroendocrine Cells; secrete
        
        Chemical messengers, both paracrine (histamine) & hormonal (gastrin)
      - Duodenal Glands
        
        Submucosa of duodenum, secrete alkaline mucus to neutralize acidic chyme
      - Intestinal Crypts
        
        Tubular glands scattered between villi in SI
        
        Enterocytes produce intestinal juice to aid in absorption of nutrients from chyme
        
        Goblet cells secrete mucus
        
        Enteroendocrine cells source of enterogastrones (CCK & secretin)
        
        Paneth cells secrete antimicrobial agents (defensins & lysozymes)