Download Histology of the digestive system

Histology of the digestive
system
Gastrointestinal tract (GI tract)
1. Mouth:
a. Internal: nonkeratinized stratified squamous
epithelium
b. Middle: buccinator muscles, bone
2. pharynx: skeletal muscle; nonkeratinized
stratified squamous epithelium
3. esophagus:
a. nonkeratinized
stratified squamous
epithelium
b. skeletal
(superior); smooth
muscle (inferior)
4. esophagus to anal canal
Deep to superficial
• Mucosa
– Epithelium: touches food
• Nsse – protection
• Simple columnar (stomach/intestines)–
secretion/absorption
• exocrine cells (mucus)
• endocrine cells (hormones)
– Lamina propria (conn.)- blood/lymph vessels,
MALT
– Smooth muscle – makes folds, inc. SA
• Submucosa
– Binds mucosa to muscularis
– Blood/lymph vessels/neurons
• Muscularis
– Skeletal muscle until middle esophagus
(swallowing); external anal sphincter
– Smooth muscle
• Inner: circular fibers
• Outer: longitudinal fibers
• Serosa: connective and simple squamous
epithelium (reduce friction)
pancreas
• Small clusters of
glandular epithelial
– 99%: called acini
(exocrine function –
secrete pancreatic
juice for digestion)
– 1%: called pancreatic
islets (endocrine
function)
liver
• Consists of many lobules
– Contains epithelial cells called hepatocytes arranged
irregularly around a central vein. Capillaries, called
sinusoids, are highly present and contain fixed
phagocytes (to removed WBCs and RBC, bacteria,
etc)
gallbladder
• Mucosa is simple columnar epithelium