Digestion Lecture Notes

Vocabulary flashcards about Digestion.

Mechanical Processing

The mechanical processing of food in the mouth reduces particle size and exposes surface area to digestive enzymes.

Motility

The movement of food along the digestive tract through muscle contractions.

Secretion

The process where digestive enzymes and gastric juices are released into the gut.

Digestion

The breakdown of nutrients within the gut by enzymes into absorbable units.

Absorption

The uptake of nutrients from the gastrointestinal tract into the body.

Excretion

The elimination of undigested food from the body in faeces.

Enzymatic Digestion

Digestion by enzymes produced by our body.

Fermentative Digestion

Digestion by enzymes produced by microbes in our gut.

Mucosa

Layer closest to the surface of the gut, containing endocrine and exocrine glands.

Submucosa

Layer containing a nerve plexus and major blood and lymph vessels.

Muscularis Externa

Layer containing circular and longitudinal muscles for moving food through the gut.

Serosa

The outer layer that connects the gut to the rest of the body.

Exocrine Glands

Secrete digestive enzymes and gastric juices into the gut.

Endocrine Cells

Produce hormones that go into our blood to modify the rate of digestion.

Enteric Nervous System

The intrinsic nervous system of the gut.

Neurotransmitters

Chemicals that transmit signals between cells.

Saliva

Important for lubricating food for swallowing and contains amylase to digest starches.

Amylase

An enzyme in saliva that helps to digest starches.

Pavlov

A physiologist who discovered the conditional reflex through experiments with dogs.

Esophagus

A tube that moves food from the mouth to the stomach.

William Beaumont

A surgeon who experimented on Alexis St. Martin to study digestion.

Alexis St. Martin

A man with a hole (fistula) in his stomach who was the subject of experiments by William Beaumont.

Fistula

A hole in the stomach.

Stomach

A short-term reservoir for food that mixes and grinds food into liquids.

Pyloric Sphincter

Controls food release into the small intestine.

Acid Secreting Cells

Cells in gastric pits that produce hydrochloric acid.

Zymogen

An inactive form of an enzyme.

Pepsinogen

A zymogen that is converted into pepsin.

Pepsin

An active enzyme that digests protein, activated by hydrochloric acid.

Helicobacter Pylori

A bacteria is the main cause of stomach ulcers.

Duodenum

The first part of the small intestine.

Jejunum

The middle part of the small intestine.

Ileum

The last part of the small intestine.

Villi

Small, finger-like projections in the small intestine that increase surface area for absorption.

Microvilli

Microscopic projections on the cells of the villi that further increase surface area for absorption.

FODMAPs

Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.

Xenical

A weight loss drug that inhibits the production of lipase, reducing fat digestion.

Cecum

A small blind sack at the start of the large intestine.

Appendix

An organ attached to the cecum.

First Pass Metabolism

Process where the liver modifies nutrients and toxins before sending them around the body.