Human Digestive System Practice Flashcards

Comprehensive vocabulary flashcards covering the human digestive system, including organ functions, enzymes, hormones, and anatomical terms described in the lecture notes.

Phonation

The modification of sound, which is a role played by the lips.

Mastication

The process of physically breaking down ingested food by the teeth, commonly known as chewing.

Sublingual glands

A pair of salivary glands situated below the tongue.

Submaxillary glands

A pair of salivary glands located behind the jaws.

Parotid glands

A pair of salivary glands located in front of the ears.

Bicarbonate ions

Components of saliva that buffer chemicals in the oral cavity.

Thiocyanate ions

Components of saliva that kill microorganisms.

Salivary amylase

An enzyme in saliva that partially digests polysaccharides (starch and glycogen) into disaccharides (maltose).

Bolus

A small moist mass of food formed after the mechanical and chemical digestive processes in the oral cavity.

Pharynx

A cavity behind the mouth that serves as the common passageway for both the digestive and respiratory tracts.

Epiglottis

A flap of cartilage that lowers during swallowing to close the opening of the trachea.

Oesophagus

A tube approximately $25\,cm$ long in adult humans that connects the pharynx to the stomach.

Cardiac sphincter

Also known as the lower oesophageal sphincter, it opens in response to food pressure and prevents backflow of stomach contents.

Peristalsis

The rhythmic sequence of waves of contraction in the smooth muscles of the walls of the alimentary canal.

Segmentation

The back-and-forth movement in the intestines created by the contraction and relaxation of smooth-muscle rings to mix food with secretions.

Antiperistalsis

The reversal of peristaltic movements that pushes food from the intestines back into the stomach and oral cavity, leading to vomiting.

Hunger pangs

The uncomfortable sensation created by peristaltic movements triggered by low blood glucose levels.

Pyrosis

Also known as heartburn, it is a painful burning sensation in the chest caused by the backflush of acidic chyme into the oesophagus.

Parietal (oxyntic) cells

Cells in the mucosa of the stomach that secrete hydrochloric acid to adjust pH to $2-3$.

Chief cells

Cells in the gastric glands of the stomach that secrete the enzyme pepsinogen.

Gastric juice

The collective name for all secretions produced by the gastric glands.

Chyme

The semi-liquid acidic mass of food content formed in the stomach three to four hours after a meal.

Gastrin

A hormone released by stomach mucosa that stimulates gastric glands to produce and secrete more gastric juice.

Somatostatin

A hormone that stops the release of hydrochloric acid when food moves from the stomach to the small intestine.

Duodenum

The first $20-25\,cm$ portion of the small intestine concerned with the digestion of food.

Enterokinase

An enzyme secreted by the walls of the duodenum that activates trypsinogen into trypsin.

Bile

A secretion from the liver stored in the gallbladder that emulsifies fats into small droplets.

Jaundice

A condition caused by the accumulation of bile pigments in the blood if they are prevented from leaving the digestive tract.

Chyle

The alkaline emulsion produced in the small intestine after the action of intestinal juice enzymes on chyme.

Villi

Numerous finger-like projections in the jejunum and ileum that increase surface area for absorption.

Lacteal

A vessel of the lymphatic system located within each villus of the small intestine.

Chylomicrons

Small protein-coated droplets of triglycerides formed within the epithelial cells of villi during fat absorption.

Vermiform appendix

A vestigial finger-like process arising from the blind end of the caecum.

Vitamin K

A vitamin produced by bacteria like E. coli in the colon that is necessary for the coagulation of blood.

Secretin

A hormone released by duodenal walls stimulated by chyme acidity that triggers the release of pancreatic juice and bile.

Cholecystokinin (CCK)

A hormone secreted by the duodenal walls in response to partially digested proteins and fats to stimulate the pancreas and gallbladder.