BIO 241 HISTOLOGY REVIEWBIO 241 HISTOLOGY REVIEWDigestive SystemDigestive System

Dr. Tim BallardDr. Tim Ballard

Department of Biology and Marine BiologyDepartment of Biology and Marine Biology

Basic histological plan of the GI tractBasic histological plan of the GI tract

EsophagusEsophagus

Arrow = epithelium of trachea M = mucosa SB = submucosaME = muscularis externa A = adventitia

EsophagusEsophagus

Arrow = epithelium ME = muscularis externa Arrowheads = Blood vessels in the submucosa

EsophagusEsophagus

Arrow = duct of mucous secreting gland in the submucosa

mucous gland

stratified squamous epithelium

EsophagusEsophagus

stratified squamous epithelium

muscularis externa

inner circularouter

longitudinal

adventitia

submucosa

StomachStomach

Fundic StomachFundic Stomach

Arrowhead = muscularis mucosae Arrow = muscularis externa

Arrowhead = neck mucous cells

Typical gastric glandTypical gastric gland

parietal cellschief cells

Arrow = muscularis mucosae ME = muscularis externa

Stomach wallStomach wall

parietal cells

chief cells

submucosa

Arrow = gastric glands Arrowheads = lymphocytes

Pyloric stomachPyloric stomach

Curved Arrow = villus Arrow = Brunners gland Arrowhead = lymphatic tissue

Duodenum Duodenum

mus

cular

is

exte

rna

intestinal gland

V = villi S = submucosa PC = plica circularis M = mucularis mucosa arrowheads = intestinal glands

Ileum Ileum

Ileum Ileum

Arrow = Peyers patches Arrowhead = mesentery

villus

Arrow = smooth muscle of taenia coli

Colon Colon

mucosa

no villi

submucosa

muscularis

Colon Colon

goblet cells

simple columnar cells

LiverLiver

Arrowhead = capsule Arrows = interstitial c.t. Curved arrow = central vein

lobule

portal triad

Liver – portal triadLiver – portal triad

A = Hepatic artery B = Portal vein C = bile duct

simple cuboidal epithelium

Liver – hepatocytes and sinusoidsLiver – hepatocytes and sinusoids

A = central vein B = Portal tract

Look for sinusoids as the spaces between cords of hepatocytes

Liver – bile canaliculiLiver – bile canaliculi

Arrowhead = endothelium of central vein

sinusoidLook for canaliculi between

adjacent rows of hepatocytes

Pancreas -- lobulesPancreas -- lobules

Arrow = Islets of Langerhans Arrowhead = septa

lobule

lobule

lobule

lobule

Pancreas -- acinusPancreas -- acinus

interlobular duct

connective tissue

acini