digestive system

• functions of the digestive system


  ingestion

  food storage

  digestion

  absorption

  assimilation

  intermediary metabolism

  elimination

  endocrine

  excretion

  bodily defense
• general mucosa

  lamina propria

  muscularis mucosae
• general lamia propria

  loose CT

  has blood vessels, nerves, macrophages, lymphocytes, plasma cells
• general muscularis mucosae

  one or two thin layers of smooth muscle

  some skeletal muscle in esophagus
• general submucosa

  loose CT

  blood vessels, nerves, lymphatics

  submucosal plexus
• general submucosal plexus

  part of enteric NS

  supplies glands
• general muscularis externa

  smooth muscle

  inner circular layer

  myenteric plexus

  outer longitudinal layer

  coordinated contraction = peristalsis
• general myenteric plexus 


  part of enteric NS

  supplies the muscle
• general adventitia

  outside peritoneal cavity

  fibrous CT (blends with nearby CT)
• general serosa

  in peritoneal cavity

  visceral peritoneum

  simple squamous mesothelium

  deeper fibrous CT layer
• oral mucosa

  lining mucosa

  NKSSE
• masticatory mucosa

  on gingivae (gums) and hard palate

  KSSE or PKSSE

  dermal papillae tall/deep
• specialized mucosa

  on tongue's upper surfaces and sides

  mix of NKSSE and KSSE

  keratinization varies
• tongue is covered with

  papillae

  taste buds
• the tongue has underlying skeletal muscles at perpendicular angles.
• filiform papillae

  most abundant

  smallest

  cover upper surface of tongue

  concial

  lack taste buds

  keratinized on upper tips

  not well vascularized (white / gray)
• fungiform papillae

  on upper surface of tongue

  most are at tip of tongue

  mushroom shaped

  NKSSE or slightly KSSE

  vascularized (red)

  single taste bud on top
• circumvallate papillae


  at back of tongue

  largest

  surrounded by clefts

  taste buds on sides of papilla
• foliate papillae

  on sides of tongue

  surrounded by clefts

  taste buds on sides of papilla
• taste buds

  lightly stained

  oval

  3 cell types
• cell types of taste buds


  gustatory cells

  sustentacular cells

  basal cells
• gustatory cells

  sensory

  has microvilli

  chemical stimuli
• sustentacular cells

  support

  has microvilli
• basal cells (of the taste bud)


  small stem cells producing the other two types of cells
• primary salivary glands

  parotid

  sublingual

  submandibular
• saliva

  water, mucus, enzymes, antibodies and electrolytes
• serous acini

  watery secretion with enzymes and antibodies

  basophilic

  granular cytoplasm
• mucous acini

  pale with smooth cytoplasm

  nuclei closer to basement membrane

  secretion is viscous
• serous demilunes

  serous cells forming cap over mucous cells
• myoepithelial cells

  assist in moving secretion into ducts
• gland capsules send septa into gland and divides it into lobules.
• striated ducts

  radial striations

  nuclei in the middle of the cell
• enamal

  hardest material in the body
• cementum

  bone like material

  lacks haversian system and blood vessels of bone
• peridonal ligaments

  connects cementum with alveolar bone

  acts as periosteum
• dentin

  70% calcium salts
• tooth roots

  found in alveoli (sockets) or bone
• pulp cavity

  filled with vascular loose CT

  has dental pulp
• esophagus

  long muscular tube from pharynx to stomach

  relaxed is high folded

  closed by sphincter muscles at each end
• esophagus mucosa

  NKSSE

  highly folded when relaxes

  esophageal cardiac glands in lamina propria

  thick muscularis mucosae