Digestive System and Enzymes Review

These flashcards cover key terms and concepts related to the digestive system, including sphincters, enzymes, and the actions of specific cells.

Sphincters

Muscular rings that control the passage of substances in the digestive system.

Cardiac sphincter

The sphincter that relaxes to allow food to enter the stomach.

Pepsinogen

An inactive precursor of pepsin that is secreted by chief cells in the stomach.

Hydrochloric acid (HCl)

An acid secreted by parietal cells, necessary for protein digestion and activating pepsinogen.

Intrinsic factor

A substance produced by parietal cells that is essential for the absorption of vitamin B12.

Pepsin

An active enzyme that breaks down proteins into peptides in the stomach.

Gastric lipase

An enzyme produced by chief cells that digests lipids.

Macula densa

Cells located in the nephron that sense sodium concentration and help regulate kidney function.

Net filtration pressure

The difference between hydrostatic pressure and osmotic pressure in the kidneys, influencing filtration.

Mesangial cells

Specialized cells in the kidney that provide structural support and can regulate blood flow.

Colloidal osmotic pressure

The pressure exerted by proteins in the blood that pulls water into the circulatory system.

Amylase

An enzyme that initiates starch digestion in the mouth.

Lactase

An enzyme that breaks down lactose into glucose and galactose.

D vs L glucose

Stereo isomers of glucose, differing in molecular configuration.

Brush border enzymes

Enzymes located on the microvilli of the small intestine that further digest carbohydrates and proteins.

Chyme

The semi-fluid mass of partly digested food that is expelled by the stomach into the small intestine.

Iron reduction

The conversion of dietary iron to a more absorbable form (Fe2+) by stomach acid.

Nucleic acid enzymes

Enzymes that digest nucleic acids, produced by the pancreas.

Somatostatin

A hormone that inhibits the release of other hormones, secreted by delta cells in the pancreas.

Enteroendocrine cells

Cells in the gastrointestinal tract that release hormones regulating digestive processes.