Terminology

Accessory Organs - A

Organs which aid in digestion

• Salivary glands (secrete saliva, which contains enzymes that start breaking down carbohydrates)

• Liver (Produces bile and emulsifies fat)

• Gallbladder (Stores bile and releases into small intestine)

• Pancreas (Produces and secretes pancreatic juice, containing digestive enzymes and bicarbonate ions into small intestine)

Gastrin - P

Helps increase mucosal production in the pyloric region. Parasympathetic impulses from the vagus nerve tell certain stomach cells to produce gastrin, increasing their secretory activity. This works alongside the supression of somatostatin by releasing acetylcholine, which is the hormone that inhibits acid secretion. It also stimulates cell growth in the mucosa of the stomach and intestines, except where gastrin is produced, replacing mucosal cells that are damaged.

Parotid Gland - A

Largest of the salivary glands; lies anterior and somehwat inferior to cheek; secretes clear, watery fluid rich with amylase into the mouth

Alimentary Canal - A

Passage from mouth to anus which food passes through; includes the esophagus, stomach, and intestines

Layers:

• Mucosa/Mucus membrane: Innermost; formed of surface epithelium, connective tissue, and smooth muscle

• Submucosa: Contains loose connective tissue, as well as glands, vessels, and nerves

• Muscular layer: 2 layers of muscle, one goes lengthwise and one changes diameter

• Serosa/Serous layer: Outer covering of tube, composed of the visceral peritoneum, which secretes serous fluid

Haustra - A

Pockets in the large intestine which give it it’s bubbled shape.

Pepsin - P

Secreted by chief cells, and helps break down almost all types of dietary protein. Starts off as pepsinogen, and then is activated by hydrochloric acid and turned into pepsin. Works best in acidic environments.

Amylase - P

Enzyme which begins the process of changing complex sugars (starches) into simple sugars during digestion.

Hepatic Duct - A

Lobules converge to form multiple ducts, which also converge to form the hepatic duct

Pepsinogen - P

Secreted by chief cells, and turns into pepsin after being activated by hypochloric acid.

Anus - A

Opening at the end of the large intestine, after the rectum; mucosal membrane folds into anal columns; two sphincter muscles, one voluntary and one involuntary

Hepatic flexure - A

Right colic flexure; between transverse colon to descending colon

Peptidase - P

Splits peptides into amino acids; found in small intestine

Ascending Colon - A

Initial part of the colon; absorbs water and key nutrients to solidify the rest as stool; from posterior abdominal wall to just inferior of liver

Hepatopancreatic Ampulla - A

Small ampulla between common bile duct and pancreatic dinner

Peristalsis - A

Wavelike motion which propels the food through the alimentary canal; begins when food expands the tube

Bicarbonate ions - P

Raises the internal pH of the stomach, after acidic juices complete digestion; regulates the pH in the small intestine

Hepatopancreatic Sphincter - A

Sphincter that regulates flow of hepatic and pancreatic substances to the small intestine; located in the duodenum

Pharynx - A

Space between mouth and esophagus; connects the nasal and oral cavities with the larynx and esophagus

Bile - A

Liquid made of mostly bile salts; made by liver and stored in gallbladder; helps with digestion; breaks down fats into fatty acids; contains bile salts, bile pigments, cholesterol, and electrolytes

Ileocecal Sphincter - A

Between small intestine’s ileum and large intestine’s cecum; relaxed by peristalsis

Plicae Circulares - A

Folds in the duodenum which are crescent-shaped; do not disappear when distended (stretched out)

Body of the Stomach - A

J-shaped organ that digests food; produces enzymes and acids to pass on food into small intestine

Ileum - A

Small intestine after the jejunum.

Proteins - A

Important for muscle growth; amino acids; takes longer than carbohydrates to break down

Bolus - A

Mass of food that is in a tube-like structure of the body, like food in the digestive tract

Internal anal sphincter - A

Involuntary sphincter controllling the excretion of feces

Pyloric Sphincter - A

Location in the pylorus, controls gastric emptying

Carbohydrates - P

Sugars; short-term energy; vegetables, bread; simple and complex carbohydrates

Intestinal flora - P

Gut microbiota; helps with absorbing nutrients

Pylorus - A

Lower area of stomach, circular muscles thicken to create the pyloric sphincter.

Carboxypeptidase - P

Protein splitting (proteolytic) enzymes from the pancreatic juice; activated by the enzyme tryspin.

Intrinsic Factor - P

A factor of the gastric juice; it helps with vitamin B₁₂ absorption from the small intestines.

Rectum - A

After the sigmoid colon; next to colon; ends right before the coccyx, where it becomes the anal canal

Cardia of the Stomach - A

Area near the esophogeal opening, has the cardiac sphincter;

Jejunum - A

Proximal two-fifths of the “free” small intestine (after the duodenum); thicker diameter, more vascular, and more active than the ileum.

Rugae - A

Deep ridges in the inner mucosal and semimucosal membranes of the stomach.

Cecum - A

Beginning of the large intestine, connection between large and small intestines

Lactase - P

Splits lactose into glucose, fructose, and galactose; found in small intestine

Secretin - P

Stimulates the pancreas to secrete a large quality of fluid when acidic chyme enters the duodenum; the pancreatic juice has very few digestive enzymes, but a high concentration of bicarbonate ions.

Chemical Digestion - A

Use of enzymes to break down and absorb nutrients from the bolus’ of foods.

Large Intestine - A

Larger diameter than small intestines; final organ of the digestive system; contains cecum, colon, rectum, and anus.

Serous - P

Cells which produce a watery fluid, that contains the enzyme amylase

Chief Cells - P

Release pepsinogen, which is activated by either pepsin cells or hydrochloric acid from parietal cells to create pepsin. This helps break down proteins.

Lingual Frenulum - A

Small tissue which connects the tongue to the bottom of the mouth.

Sigmoid Colon - P

S-shaped colon which turns turns into the rectum

Cholecystokinin - P

Released in the intestinal phase of gastric secretion; when food enters the small intestine, the hormone cholecystokinin is released, decreasing gastric motility (ability to move by oneself). Released by the upper small intestines; stimulates the release of bile from gallbladder

Lipase - P

Breaks down fats into fatty acids and glycerol

Small Intestine - A

Where the main absorption occurs

Chyme - A

Paste of food particles and gastric juices; pushed little by little into the small intestine; created by the mixing movements in the stomach

Liver - A

Largest internal organ; 4 lobes; functional units are hepatic lobules;

Soft Palate - A

Back part of the roof of your mouth

Chymotrypsin - P

Protein splitting enzyme, found in pancreatic juice; activated by trypsin.

Lower Esophageal Sphincter - A

Closes connection between esophagus and stomach, preventing regurgitation from stomach; relaxed by peristalsis; aka cardiac sphincter

Splenic flexure - A

Left turn between ascending colon and transverse colon.

Colon/Large Intestine - A

Final part of GI tract; carries from small intestine to anus

Maltase - P

Splits maltose into glucose, fructose and galactose; found in small intestine

Stomach - A

J-shaped, pouch-like organ; upper left portion of abdominal cavity; has rugae (thick folds) in the inner layer; recieves food from esophagus, mixes with gastric juice, iniates digestion of proteins, carries on limited absorption, and moves food into small intestine.

Common Bile Duct - A

Formed by union of hepatic and cystic ducts; usually closed, causes bile to back up into gallbladder; fills gallbladder with bile

Mastication - P

Process of chewing and grinding the food in the mouth using the teeth and jaws; helps create a bolus of food.

Sublingual Gland - A

Smallest of major salivary glands; inferior to the tongue; many ducts; majority mucous; thick and stringy

Cystic Duct - A

Separate duct which is connected with teh common bile duct

Mechanical Digestion - P

Physically breaking down food into smaller particles, for it to go through chemical digestion better.

Submandibular Gland - A

Located in the floor of the mouth, inside lower jaw; opens near the lingual frenulum; mostly serous, with few mucous cells

Defecation - P

Elimination of indigestible parts of food; after digestion

Mesentery - A

Folds of tissue which connect the small intestines to the abdominal wall; has blood vessels.

Submucosa - A

Layer beneath the mucosa

Descending Colon - P

Between descending colon and sigmoid colon

Microvilli - A

Increase surface area in small intestines

Sucrase - P

Splits sucrose into glucose, fructose and galactose; found in small intestine

Duodenum - A

First 12 inches of the small intestines

Mouth - A

First portion of alimentary canal; mechanically breaks down the food

Teeth - A

Aid in mastication; found in the mouth; hardest structures of body

Emulsification - P

The process of breaking down fat molecules; Bile salts help break down the fats into smaller chunks, which increases total surface area and allow lipases to digest them more efficiently.

Mucosa - A

Innermost layer of GI tract

Teniae Coli - A

Bands of thickened smooth muscle around the length of the large intestine; aids with peristalsis

Enterokinase - P

Turns trypsinogen into trypsin

Mucus/Goblet Cells - P

Secrete mucus, which helps bind food particles and acts as a lubricant during swallowing.

Tongue - A

Strong muscular organ; covered in mucous membrane; mixes food particles with saliva; contains papillae which have taste buds

Esophagus - A

Straight, collapsible tube that takes the food from mouth to stomach; has mucosal glands throughout; peristalsis moves food along the esophagus

Muscular - P

Helps contractions, like peristalsis, to move food across the GI tract

Transverse Colon - P

Longest and most moveable part of the large intestine

External anal sphincter - A

Voluntary sphincter which controls the excretion of feces.

Palatine Tonsils - A

On either side of the tongue; beneath the epithelial lining of mouth; protect body against infections

Trypsin - P

Protein splitting enzyme released by pancreas, Released as the inactive trypsinogen, but activated by the enzyme enterokinase (secreted by small intestines); trypsin then activates chymotrypsin and carboxypeptidase

Fats - P

Triglycerides, monoglycerides; difficult to break down

Pancreas - A

Organ which releases pancreatic juice; found inferior to the stomach

Trypsinogen - P

Inactive version of trypsin, released by pancreas; activated by the enzyme enterokinase, which is secreted by the small intestines.

Fundus - A

Superior to cardiac region, temporary stoarage and may balloon to hold swallowed air

Pancreatic Duct - A

Connects with bile duct to bring bile from pancreas to gallbladder.

Uvula - A

Projection in the middle of mouth

Gallbladder - A

Storage of bile between meals; releases it into duodenum when stimulated by cholecystokinin

Pancreatic Juice - A

Secreted by pancreas; high in bicarbonate ions, making it alkaline (base); contains enzymes that digest carbohydrates, fats, proteins, and nucleic acids;

• Pancreatic lipase - Breaks down fat

• Trypsin, chymotrypsin, and carboxypeptidase - Breaks down protein

• 2 types of nucleases - Break down nucleic acids

Vermiform appendix - A

Narrow tube with closed end of the cecum; contains lymphatic tissue and microbiota.

Gastric Juice - A

Combination of digestive enzymes and hydrochloric acid; contains pepsin, which is first created by chiefs cells as pepsinogen, and reacts with hydrochloric acid from parietal cells to create pepsin, it helps break down almost all types of proteins, and works best in an acidic environment (like hydrochloric acid)

Parietal Cells - P

Release hydrochloric acid, which contributes to the gastric juice. This hydrochloric acid provides an acidic environment for pepsin to work better. It also creates activates pepsinogen into pepsin.

Villi - A

Fingerlike projections that increase surface area.