Canine and Feline Gastrointestinal Anatomy and Physiology Flashcards

Vocabulary flashcards focusing on gastrointestinal anatomy, cell types, enzymes, and digestive physiology concepts in dogs and cats.

Autoenzymatic Digestion

Hydrolytic digestion carried out by enzymes produced directly by the host animal.

Alloenzymatic Digestion

Fermentative digestion carried out by enzymes derived from microbial populations.

Gut-Associated Lymphoid Tissue (GALT)

The body's largest immune organ, located in Peyer's patches, which samples and processes antigens to generate B cells and secretory IgA.

Pre-Gastric Fermentation

Fermentation occurring proximal to hydrolytic/enzymatic digestion, found in species such as ruminants, pseudoruminants, hippopotamuses, marsupials, and herbivorous monkeys.

Post-Gastric Fermentation

Fermentation occurring distal to hydrolytic/enzymatic digestion, observed in dogs, cats, humans, pigs, rodents, rabbits, and large herbivores.

Carnassial Teeth

Specialized teeth (the $3\text{rd}$ premolar) found in carnivores that function like scissors to slice flesh.

Parietal Cells

Gastric mucosal cells that secrete hydrochloric acid ($HCl$) to denature proteins and maintain a stomach pH between $1.5$ and $2.5$.

Chief Cells

Gastric mucosal cells responsible for secreting gastric lipase and pepsinogen, an inactive zymogen precursor.

Foveolar Cells

Gastric cells that produce mucus to protect the stomach epithelium from pepsin and gastric acid.

Ghrelin

A short-term feeding signal secreted by P/D1 cells that increases appetite, stimulates food consumption, and decreases energy expenditure.

Enterocytes

Absorptive cells accounting for approximately $90\text{ }\text{percent}$ of small intestinal epithelial cells, functioning as the primary organ site of nutrient absorption.

Goblet Cells

Secretory cells making up about $5\text{ }\text{percent}$ of small intestinal cells that secrete mucus for protection and lubrication.

Paneth Cells

Innate immune secretory cells at the crypt base of the small intestine that secrete antimicrobial proteins such as lysozyme and defensins, having a slow turnover of $3\text{ weeks}$.

Endopeptidases

Proteolytic enzymes, including trypsin, chymotrypsin, and elastase, that break internal amino acid peptide bonds.

Exopeptidases

Proteolytic enzymes, including carboxypeptidase A and B, that cleave terminal amino acid bonds.

Trypsin

A pancreatic endopeptidase that specifically cleaves basic amino acids, namely Arginine and Lysine.

Chymotrypsin

A pancreatic endopeptidase that specifically cleaves aromatic amino acids, namely Phenylalanine, Tyrosine, and Tryptophan.

Elastase

A pancreatic endopeptidase that specifically cleaves aliphatic amino acids, including Glycine, Alanine, Valine, Leucine, and Isoleucine.

SGLT-1

Sodium-dependent glucose transporter-1, an active transporter on the apical/luminal surface of enterocytes that absorbs glucose and galactose.

GLUT5

A transporter on the apical/luminal surface of enterocytes that absorbs fructose.

GLUT2

A basolateral hexose transporter that moves glucose, galactose, and fructose out of the enterocyte into the blood vessel.

Colipase

A pancreatic secretion that changes the conformation of pancreatic lipase and opens its active site to enable proper fat breakdown.

Taurine

An amino acid derivative exclusively used by dogs and cats to conjugate bile acids, which they cannot substitute with glycine.

Short-Chain Fatty Acids (SCFA)

Fermentative end-products of carbohydrate breakdown, consisting primarily of acetate ($\text{approximately }60\text{ }\text{percent}$), propionate ($\text{approximately }25\text{ }\text{percent}$), and butyrate ($\text{approximately }15\text{ }\text{percent}$).

Branched-Chain Fatty Acids (BCFA)

End-products making up $20\text{ }\text{percent}$ of total SCFA during protein fermentation, formed through the deamination of branched-chain amino acids.