The Human Digestive System

Flashcards about the human digestive system.

Topics covered in the lecture

Parts and functions of the digestive system, the pathway of food, digestive processes, care of the digestive system, and interaction with other bodily systems.

Mechanical Digestion

Physical breakdown of food by teeth and tongue in the mouth, and churning in the stomach and small intestine.

Chemical Digestion

Enzymatic reactions that improve digestion of carbohydrates, proteins, and lipids.

Enzymes

Chemicals that speed up the rate of chemical reactions in the body.

Gastrointestinal (GI) tract

Direct link between organs, composed of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and rectum.

Mouth function

Mechanically break down food into small pieces and mixes it with saliva (containing salivary amylase for starch digestion).

Epiglottis

Flap-like structure that prevents food from entering the trachea.

Esophagus function

Secretes mucus and moves food to the stomach using peristalsis.

Lower Esophageal Sphincter (LES)

Muscular ring that controls the flow of food from the esophagus into the stomach and prevents reflux.

Stomach function

J-shaped muscular bag that stores and breaks down food, mixes it with digestive juices, and contains acid to kill bacteria.

Chyme

Food found in the stomach.

Proteases

Enzymes that chemically digest proteins (e.g., pepsin).

Small Intestine

Where main fat digestion occurs, specifically in the duodenum.

Bile

Yellow-green fluid secreted by the liver, stored in the gall bladder, that emulsifies fats.

Emulsification

Breaking of fats into smaller droplets.

Villi

Finger-like projections in the small intestine that increase surface area for absorption.

Microvilli

Further increase surface area for absorption in the small intestine.

Lipase

Enzymes that chemically digest fats in the small intestine.

Large Intestine

Accepts what small intestines don’t absorb; no digestion occurs here.

Beneficial bacteria (gut flora/microbiota)

Break down carbohydrates and proteins

Rectum

Short-term storage for feces before expulsion.

Anus

Opening at the end of the rectum for solid waste to leave the body.

Anal sphincter

Ring of muscle that controls the release of stool during defecation.

Accessory Organs of Digestive System

Liver, gall bladder, and pancreas.

Liver function

Produces bile to help break down fat and filters out toxins and waste.

Gall Bladder function

Stores bile from the liver and releases it into the small intestine.

Pancreas function

Produces digestive enzymes and regulates blood sugar by producing insulin.

Ingestion

The act of taking food into the mouth.

Propulsion

The movement of food through the digestive tract by swallowing and peristalsis.

Mechanical Digestion

Physical breakdown of food into smaller pieces.

Chemical Digestion

Breakdown of complex food molecules into simpler substances using enzymes and digestive juices.

Absorption

Nutrients from digested food are taken into the bloodstream or lymph.

Assimilation

Absorbed nutrients used by body cells for energy, growth, and repair.

Egestion (Defecation)

Removal of undigested and unabsorbed food as feces.