Digestive system - A/P

Food pathway?

Mouth → pharynx → esophagus → stomach → small intestine → large intestine (colon) → rectum → anus

Ingestion

Taking food into mouth

Digestion

Breaking down food

Functions of digestive system

Ingestion, propulsion, mechanical digestion, chemical digestion, absorption, and defecation

Uvula

Flap that closes off nasal cavity during swallowing

Salivary glands

Produce saliva with enzymes (like amylase)

Mastication

Chewing (mechanical digestion that increases surface area)

Amylase

Enzyme that breaks down starch/carbohydrates

Pharynx

Throat; passage from mouth to esophagus

Deglutition (swallowing)

Process of moving food from mouth to stomach

Correct order in swallowing

Mouth (voluntary) → pharynx → esophagus (involuntary)

Peristalsis

Wave-like muscle contractions that move food through GI tract

Cardiac sphincter (lower esophageal)

Controls entry of food into stomach

Pyloric sphincter

Controls exit of stomach contents into small intestine

Rugae

Folds in stomach that allow expansion

Mucous cells

Secrete mucus to protect stomach lining

Function of mucus in stomach

Protects lining from acid and enzymes

Intrinsic factor

Protein needed for vitamin B12 absorption

What does pepsin do?

Enzyme that breaks down proteins

Chyme (makeup and flow)

Semi-liquid mixture of food + acid + enzymes and flows from stomach → small intestine

Pancreas

Produces digestive enzymes

CCK (cholecystokinin)

Hormone that triggers bile release + pancreatic enzymes

Bile

Breaks down fats (emulsification)

Colon regions in order

Ascending → transverse → descending → sigmoid colon

Mechanical digestion

Physical breakdown (chewing)

Chemical digestion

Enzymes break molecules into nutrients