Chapter 14: Digestive System

• functions of digestive system

  ingestion

  food storage

  digestion

  absorption

  assimilation

  intermediary metabolism

  elimination

  endocrine

  excretion

  bodily defense
• tube within a tube

  mouth

  pharynx

  esophagus

  stomach

  small intestine

  large intestine

  rectum

  anal canal

  anus
• small intestine layers

  duodenum

  jejunum

  ileum
• large intestine

  ascending colon

  transverse colon

  descending colon

  sigmoid colon
• layers: out to in

  peritoneum

  longitudinal smooth muscle

  myenteric plexus

  circular smooth muscle

  submucosal plexus

  submucosa

  muscularis mucosae

  lamina propria

  mucosal epithelium

  lumen
• lips

  oral sphincter

  skeletal muscle
• oral mucosa


  epithelial lining inside mouth

  mostly NKSSE
• three types of oral mucosa

  lining

  masticatory

  specialized
• lining mucosa


  lines inside of mouth
• lining mucosa

  lines inside of mouth

  lips, soft palate, cheeks, floor of mouth

  NKSSE

  papillae hold CT to epithelium

  accessory salivary glands branched in submucosa

  acinar glands: mix of mucous and serous
• masticatory mucosa

  on gingivae and hard palate

  KSSE or PKSSE

  taller dermal papillae
• specialized mucosa

  on tongue's upper surface/side

  NKSSE and KSSE

  skeletal muscle at perpendicular angles

  papillae with taste buds
• four types of papillae

  filiform

  fungiform

  circumvallate

  foliate
• filiform papillae


  most abundant

  smallest

  upper surface of tongue

  conical

  no taste buds

  keratinized on tips

  not well vascularized (White/grey)
• fungiform papillae


  tip of tongue

  mushroom shaped

  NKSSE or slightly KSSE

  vascularized

  single taste bud on top
• circumvallate papillae


  back of tongue

  largest

  surrounded by clefts

  taste buds on sides

  concave at top
• foliate papillae


  side of tongue

  surrounded by clefts

  sides of papilla

  convex round surface

  multiple taste buds on side
• types of cells in taste buds

  gustatory

  sustentacular

  basal
• gustatory cells


  round

  pale nuclei
• sustentacular cells


  support

  long narrow dense nucleus near basal
• basal cells


  circular

  stem cells to regenerate taste buds
• primary salivary glands: 3 types

  parotid

  sublingual

  submandibular
• primary salivary glands


  secrete saliva
• saliva


  water, ions, mucin, antibodies, lysozyme, salivary amylase
• primary salivary glands

  serous acini: serous demilunes

  mucous acini

  myoepithelial cells

  gland capsule

  septae

  lobules

  striated ducts
• enamal


  outer crown

  no haversian

  not vascularized

  high calcium content
• dentin


  less calcium

  less hard

  fills most of space
• cementum


  outer part of tooth below gum line
• pulp cavity


  filled with pulp
• pulp

  vascularized CT
• gingival pocket


  between gums and tooth
• teeth roots

  in alveoli (sockets) or bone
• esophagus


  long tube from glottis to stomach
• mucosa


  NKSSE

  highly folded when relaxed

  esophageal cardiac glands

  thick muscularis mucosae

  top ⅓ skeletal muscle

  bottom ⅔ smooth muscle
• submucosa


  CT more elastic

  esophageal glands
• Mouth gets mucus from salivary glands
• Muscularis externa


  top ⅓ skeletal muscle

  bottom ⅔smooth muscle
• most of esophagus has adventitia, the last 1 cm has serosa covering.
• stomach parts

  cardia

  fundus

  body

  pyloris (antrum)
• gastric mucosa


  folded into rugae

  simple columnar epithelium