The Digestive SystemThe Digestive System

Digestive SystemDigestive System

Alimentary canalAlimentary canal

Accessory digestive organsAccessory digestive organs

6 essential activities6 essential activities

Regulation (mechanical and chemical stimuli)

Extrinsic control

Intrinsic control

Histology of the Alimentary CanalHistology of the Alimentary Canal

The mucus secretionsThe mucus secretions FunctionsFunctions CellsCells

MucosaMucosa3 functions3 functions

Consists of three layers:Consists of three layers: a lining epithelium, lamina propriaa lining epithelium, lamina propria, , and and muscularis mucosaemuscularis mucosae

Lamina PropriaLamina Propria

Muscularis mucosaeMuscularis mucosae

Mucosa: Mucosa: Lamina Propria and Muscularis MucosaeLamina Propria and Muscularis Mucosae

Other layersOther layers

SubmucosaSubmucosa

Muscularis externaMuscularis externa

SerosaSerosa

MouthMouth

Oral or buccal cavityOral or buccal cavity

EpitheliumEpithelium

characteristiccharacteristic

Salivary GlandsSalivary Glands

4 functions 4 functions

3 (pair) Extrinsic salivary glands 3 (pair) Extrinsic salivary glands

Intrinsic salivary glandsIntrinsic salivary glands

Digestive Processes in the MouthDigestive Processes in the Mouth

PharynxPharynx

Food and fluids to the esophagusFood and fluids to the esophagus CellsCells

EsophagusEsophagus

Muscular tube, Muscularis changes enrouteMuscular tube, Muscularis changes enroute

StomachStomach

chymechyme

RegionsRegions

Nerve supply

Blood supply

Muscles of stomach

Microscopic Anatomy of the StomachMicroscopic Anatomy of the Stomach

Epithelial lining Epithelial lining

Gastric pits Gastric pits

Glands of the Stomach Fundus and BodyGlands of the Stomach Fundus and Body

Gastric glandsGastric glands

Parietal

Mucous neck cells

Chief cells

Enteroendocrine cells – secrete gastrin, histamine, endorphins, serotonin, cholecystokinin (CCK), and somatostatin into the lamina propria

Small Intestine: Microscopic AnatomySmall Intestine: Microscopic Anatomy

Plicae circularesPlicae circulares Villi Villi MicrovilliMicrovilli

Structural modifications:Structural modifications:

Cells and structuresCells and structures

LiverLiver

CellsCells

FunctionsFunctions

Hepatic Artery Hepatic Artery and Hepatic Portal Veinand Hepatic Portal Vein

The GallbladderThe Gallbladder

Function of gallbladder

Bile

Function of bile

Gallstones

BileBile

bile salts, bile pigments, cholesterol, neutral fats, phospholipids, and electrolytes

Regulation of Bile ReleaseRegulation of Bile Release

PancreasPancreas

Endocrine functionEndocrine function Islets of LangerhansIslets of Langerhans

Exocrine functionExocrine function Acini CellsAcini Cells

Pancreatic Juice and Pancreatic Juice and enzymesenzymes

Regulation of Pancreatic SecretionRegulation of Pancreatic Secretion

Large IntestineLarge Intestine

CellsCells

FunctionsFunctions

Bacterial FloraBacterial Flora

Digestive phases:Digestive phases:

OverlappingOverlapping

CephalicCephalic

GastricGastric

IntestinalIntestinal

NutritionNutrition

NutrientsNutrients

MineralsMinerals

VitaminsVitamins