Anatomy & Physiology 12 - Digestion Vocabulary #2

Nuclease

Nuclease

Hydrolytic enzymes that react with nucleic acids; they are components of both pancreatic juice and intestinal juice

Pancreas

Gland posterior to the stomach that produces the hormones glucagon and insulin as well as pancreatic juice

Amylase

An enzyme that breaks down starches into maltase; Produced by the salivary glands and pancreas

Pancreatic Juice

Exocrine secretion containing amylase, trypsin, nucleases, sodium bicarbonate, and water; water is used as a lubricant and is essential component of hydrolytic reactions; sodium bicarbonate neutralizes the stomach acid; the release of this secretion is triggered by a hormone in the duodenum

Pepsin

An enzyme that breaks down proteins into smaller peptides in digestion; it is activated from its inactive form (pepsinogen) by the HCl in gastric juice

Pepsinogen

Pre-cursor of pepsin that is activated by HCl

Peptidase

Enzymes that break down peptides into amino acids; ensures that amino acids can be absorbed by the small intestine

Peristalsis

Wave-like involuntary muscle contractions that move food through the digestive tract

Pharynx

Portion of the digestive tract between the mouth and the esophagus which serves as a passageway for food

Physical Digestion

Mechanical breaking down of food that occurs in the mouth, stomach, duodenum

Proteases

Protein-digesting enzymes that are produced in pre-cursor form to prevent activity in the cells; pepsinogen & trypsinogen

Pyloric Sphincter

Muscular ring that relaxes to allow small amounts of stomach chyme into the duodenum

Rectum

Last portion of the large intestine that compacts and stores feces until it is defecated

Salivary Amylase

AKA ptyalin; Enzyme in saliva that digests starch (& glycogen) producing maltase; it is denatured in the stomach and digested as with any other protein that is swallowed

Salivary Gland

Set of three exocrine glands that deliver mucus (water) & salivary amylase to the mouth

Salivary Juice

Produced in the mouth in consists of salivary amylase and mucus (water); Starts to break down carbohydrates into simpler sugars and moistens food making it easier to chew and swallow

Small Intestine

Longest part of the digestive tract located between the stomach & the large intestine; consists of the duodenum, ileum, and jejunum; Specialized for digestion, transport, and absorption

Sodium Bicarbonate

Buffering component of pancreatic juice that maintains the pH of the chyme at about 8.4 which is optimal for the function of pancreatic enzymes

Stomach

Muscular organ located between the esophagus and small intestine; Functions include food storage, physical digestion, and chemical digestion

Swallowing

Reflexive action that moves a food bolus through the esophagus

Trypsin

Enzyme component of pancreatic juice that is produced as the precursor trypsinogen and activated by enterokinase; Breaks down large peptides (5-7 AA) to smaller peptides (2-3 AA)

Villus

Fingerlike projection of the inner surface of the small intestine that consist of blood capillaries & lacteals; Functions in absorbing the products of digestion (nutrients)