Digestive System

Orbicularis Oris

Closes lips, purses and protrudes lips

Buccinator

Compresses cheek

Temporalis

Cheek jaw

Masseter

Prime mover of jaw closure, elevates mandible

Central incisors

Front teeth used for cutting and biting food

Lateral incisors

Assist central incisors in cutting food

Canines

Pointed teeth used for tearing food

First premolars

Crush and grind food; transitional teeth between canines and molars

Second molars

Further grind food to increas surface area for digestion

Third molars

Wisdom teeth; assist in grinding

Hard palate

Bony anterior roof of mouth; separates oral and nasal cavities

Soft palate

Muscular posterior roof; closes off nasopharynx during swallowing

Uvula

Extension of soft palate; helps prevent food from entering nasal cavity

Parotid gland

• Largest salivary gland; produces enzyme rich saliva (amylase) to begin starch digestion

• Innervated by glossopharyngeal nerve

Submandibular gland

• Produces mixes (serous + mucous) saliva; major contributor to resting saliva

• Innervated by facial nerve

Sublingual gland

• Produces mostly mucus for lubrication of food

• Innervated by facial nerve

nasopharynx

Air passage only (not involved in digestion)

oropharynx

Passageway for both food and air

Laryngopharynx

Directs food to esophagus and air to larynx

Esophagus

Muscular tube that transports food to stomach via peristalsis

Stomach

Stores food, mechanically churns it, and begins protein digestion with acid and enzymes

Rugae

Folds in stomach lining that allow expansion when food enters

Cardiac sphincter

Prevents backflow of stomach contents into esophagus

Pyloric sphincter

Controls release of chyme from stomach into duodenum

Liver

Produces bile, processes nutrients, detoxifies substances

Right lobe of liver

Largest lobe of liver

Left lobe

smaller lobe; separate by falciform ligament

Caudate lobe

Small lobe on posterior side of liver

Quadrate lobe

Small lobe on inferior surface of liver

Portal triad

Hepatic portal vein

proper hepatic artery

bile duct

Hepatic portal vein

Brings nutrient rich blood from digestive organs to liver

Proper hepatic artery

Supplies oxygenated blood to liver

Common bile duct

Carries bile to duodenum

Cystic duct

Connects gallbladder to bile duct

Common hepatic duct

drains bile from liver

Gallbladder

Stores and concentrate bile

Pancreas

Produces digestive enzymes and bicarbonate to neutralize stomach acid

Pancreatic duct

Carries pancreatic juice to duodenum

Major duodenal papilla

Entry point where bile and pancreatic enzymes enter duodenum

Small intestine

Main side of digestion and nutrient absoprtion

Villi

Finger-like projections that increase surface area for absorption

Lymphatic duct

Absorbs fats into lymphatic system

Capillary (model)

Absorbs nutrients like glucose and amino acids into blood

Intestinal crypts (Crypts of Liberkuhn)

Glands that secrete intestinal juice and antimicrobial substances (lysozyme)

Longitudinal muscle layer

Moves food forward via peristalsis

Circular muscle layer

Contriscts lumen to push food along

Muscaularis mucosa

Creates small local movements of mucosa to aid absorption

Duodenum

First part; receives bile and pancreatic enzymes

Pilcae circulares

Circular folds that slow movement and increase absorption

jejunum

Primary site of nutrient absorption

Ileum

Final section; absorbs remaining nutrients and bile salts

Ileocecal juntion

Valve between small and large intestine; controls flow of contents.

large intestine

Absorbs water and forms feces

Cecum

First part of large intestine; receives contents from ileum

Vermiform appendix

Contains lymphoid tissue; immune function

Ascending colon

Moves contents upwards on right side

Transverse colon

Moves contents across abdomen

Descending colon

Moves contents downward on left side

Sigmoid colon

S-shaped section leading to rectum

Rectum

Stores feces before elimination

Anal canal

Final passageway for defecation

Teniae coli

Three longitudinal muscle bands that create haustra

Haustra

Pouchlike segments that allow expansion