Stomach Anatomy

• Openings– Gastroesophage

al: To esophagus

– Pyloric: To duodenum

• Regions– Cardiac– Fundus– Body– Pyloric

Stomach Histology:• Layers

– Serosa or visceral peritoneum: Outermost

– Muscularis: Three layers• Outer longitudinal• Middle circular• Inner oblique

– Submucosa– Mucosa

Stomach Histology• Rugae: Folds in

stomach when empty

• Gastric pits: Openings for gastric glands– Contain cells

Small Intestine anatomy and Histology• Site of greatest amount

of digestion and absorption

• Divisions – Duodenum– Jejunum– Ileum: Peyer’s patches or

lymph nodules• Modifications

– Circular folds or plicae circulares, villi, microvilli

• Cells of mucosa– Absorptive, goblet,

granular, endocrine

Small Intestine Secretions

• Mucus – Protects against digestive enzymes and stomach

acids• Digestive enzymes

– Disaccharidases: Break down disaccharides to monosaccharides

– Peptidases: Hydrolyze peptide bonds– Nucleases: Break down nucleic acids

• Duodenal glands – Stimulated by vagus nerve, secretin

secretin increases water and bicarbonate secretion from duodenal (Brunner's) glands

Duodenum

Liver

• Lobes– Major: Left and right– Minor: Caudate and

quadrate

Blood and Bile Flow

Pancreas

Small Intestine anatomy

Large Intestine

• Cecum– Blind sac, vermiform appendix attached

• Colon– Ascending, transverse, descending, sigmoid

• Rectum– Straight muscular tube

• Anal canal– Internal anal sphincter (smooth muscle) – External anal sphincter (skeletal muscle) – Hemorrhoids: Vein enlargement or inflammation