Digestive System

Digestive System
Presentation lecture from:deltacollege.edu

Components
* Gastrointestinal (GI) tract
o Oral cavity
o Pharynx
o Esophagus
o Stomach
o Small intestine
o Large intestine
* Accessory digestive organs
o Teeth
o Tongue
o Salivary glands
o Liver
o Gallbladder
o Pancreas

Digestive system functions
* Digestion
o Breakdown of food
* Propulsion – movement along the GI tract
* Secretion – acid, bile, digestive enzymes, mucus
* Absorption of nutrients
* Elimination

Oral cavity
* Lined by stratified squamous epithelium
* Gingivae – gums
* Salivary glands

Teeth
* Crown
* Neck
* Root(s)
* Anchored in alveoli in maxilla and mandible

Peritoneum
* Serous membrane lining the abdominopelvic cavity
* Intraperitonealt
* Retroperitoneal

Peritoneal folds
* Falciform ligament
* Lesser omentum
* Mesentery
* Greater omentum
* Mesocolon

General microscopic plan of the GI tract
* Mucosa
* Submucosa
* Muscularis
* Adventitia or serosa

Esophagus
Stomach
Stomach - microscopy
* Mucosa
* Submucosa
* Muscularis
* Serosa (visceral peritoneum)

Small intestine
Small intestine microscopy
* Increased surface area
* Mucosa
* Submucosa
* Muscularis
* Serosa (mesentery)

Large intestine
* Cecum
* Ascending colon
* Transverse colon
* Descending colon
* Sigmoid colon
* Rectum
* Anus

Liver
* Location: upper right abdomen, below diaphragm
* Intraperitoneal (covered by visceral peritoneum)
* Falciform ligament – fold of peritoneum anchored to anterior abdominal wall
* Gall bladder on inferior surface
* Lesser omentum between liver and stomach

Liver – microscopy
* Liver lobules – structural and function units
* Central vein
* Portal triads – branches of bile duct, hepatic portal vein, hepatic artery
* Cords (sheets) of hepatocytes
* Hepatic sinusoids
* Kupffer cells (macrophages)

Exocrine pancreas
* Located posterior to greater curvature of stomach
* Retroperitoneal
* Pancreatic acini – groups of secretory cells – secrete digestive enzymes
* Pancreatic duct – empties into duodenum

Exocrine pancreas
Digestive system

* Components
* Functions
* Oral cavity
* Peritoneum
* Microscopic plan
* Esophagus
* Stomach
* Small intestine
* Large intestine
* Liver
* Pancreas

Digestive system.ppt