Name: lipases and bile in fat breakdown
Uploaded: 2026-08-26T08:20:28.255Z
Duration: 1 min 16 s
Channel: JoVE

K12 Standards

Alabama Course of Study Science

9-12

Human Anatomy and Physiology

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

9-12.HA.1.10

Lipid Digestion

- [Instructeur] In de mond begint de lipidenvertering wanneer de speekselklieren linguale lipase vrijgeven, een enzym dat het proces start waarmee grote vetten, zoals triglyceriden, het meest voorkomende voedingtype, afgebroken worden.
 Terwijl de lipiden naar de maag reizen, worden bijkomende enzymen, gastrische lipasen, afgescheiden.
 Omdat lipiden hydrofoob zijn, hebben ze de neiging zich samen te voegen in waterachtige omgevingen, en voorkomen zo dat de lipasen de massa afbreken.
In het duodenum van de dunne darm, bedekken galzouten de vetdruppels en zorgen ervoor dat de globules zich verspreiden en zo een emulsie cre&#xEB;ren, een waterachtige oplossing.
 Doordat er meer oppervlakte beschikbaar is, kunnen de aanwezige alvleesklierlipasen de triglyceriden hydroliseren tot kleinere componenten, meer bepaald, vrije vetzuren en monoglyceriden.
 Nu zijn deze kleinere producten klaar om geabsorbeerd te worden door de dunne darm voor verdere verwerking.

lipidenvertering

Lipiden zijn grote moleculen die over het algemeen niet in water oplosbaar zijn. Omdat de meeste spijsverteringsenzymen in het menselijk lichaam op waterbasis zijn, zijn er specifieke stappen die het lichaam moet nemen om lipiden af te breken en beschikbaar te maken voor gebruik.

<h4>Taallipase en maaglipase</h4>

Linguale lipase is een enzym dat wordt uitgescheiden door de acinaire cellen van de sublinguale klier en dat de vertering van lipiden bevordert. Hoewel het in speeksel wordt aangetroffen, speelt het slechts een minimale rol bij het afbreken van lipiden in de mond. Interessant is dat linguale lipase een pH-optimum van 3,5-6,0 heeft en pas wordt geactiveerd als het gekauwde voedsel in de zure omgeving van de maag terechtkomt. Maaglipase is een zure lipase die wordt uitgescheiden door de hoofdcellen van de maag in het maagslijmvlies.

<h4>Zure lipasen bij volwassen mensen en pasgeborenen</h4>

Linguale lipase en maaglipase omvatten de twee zure lipasen die in het menselijke spijsverteringsstelsel worden aangetroffen. Deze lipasen zijn actief in de maag, maar worden snel ge&#xEF;nactiveerd door galzuren in de twaalfvingerige darm. Samen zijn maaglipase en linguale lipase verantwoordelijk voor 10-30% van de lipidenhydrolyse die optreedt bij volwassenen, waarbij maaglipase de grootste bijdrage levert. Gezien de lage concentraties pancreaslipase en galzouten in de neonatale fase zijn de zure lipasen van cruciaal belang voor de vertering van lipiden en zijn ze verantwoordelijk voor 50% van de lipidenhydrolyse bij pasgeborenen.

<h4>Gal</h4>

Gal bevat galzouten, lecithine en van cholesterol afkomstige stoffen, waardoor het als emulgator in de twaalfvingerige darm van de dunne darm werkt. Door de emulgering van de vetdruppeltjes in de twaalfvingerige darm wordt hun oppervlakte meer dan duizendvoudig vergroot, waardoor ze beter toegankelijk worden voor pancreaslipasen.

Lipidenvertering

Lipids are large molecules that are generally not water-soluble. Since most of the digestive enzymes in the human body are water-based, there are specific ...

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Education

JoVE Core

Biology

Biologie

Genetics

Genetica

Nutrition and Digestion

Voeding en Spijsvertering

KEY TERMS AND CONCEPTS

BELANGRIJKE TERMEN EN CONCEPTEN

lipases and bile in fat breakdown

Lipases and bile help the body break down lipids, which are large molecules that do not mix well with water. Because most digestive enzymes are water-based, lipids need special steps before the body can use them.

Lingual lipase is an enzyme made by acinar cells in the sublingual gland. It is found in saliva, but it has only a small role in the mouth. Its best pH, or acidity level, is 3.5-6.0, so it becomes active after chewed food reaches the acidic stomach.

Gastric lipase is another acidic lipase. It is secreted by the gastric chief cells in the stomach lining. Lingual lipase and gastric lipase are the two acidic lipases in the human digestive system, and they work in the stomach before bile acids in the duodenum quickly inactivate them.

In adults, these two lipases account for about 10-30% of lipid hydrolysis, or fat breakdown. Gastric lipase contributes the most. In neonates, however, acidic lipases are much more important. Because pancreatic lipase and bile salts are still low, they account for about 50% of lipid hydrolysis.

Bile contains bile salts, lecithin, and cholesterol-derived substances. In the duodenum, the first part of the small intestine, bile acts as an emulsifier. Emulsification breaks large fat droplets into smaller ones and increases their surface area more than a thousand-fold, which helps pancreatic lipases work more effectively.

Lipases and Bile in Fat Breakdown

overview of human digestion

Saliva, Stomach Acid, and Gut Health

The human digestive system is monogastric, which means the stomach has one chamber for digestion. Several other animals also have monogastric digestive systems, including pigs, horses, dogs, and birds. This chapter focuses on the human digestive system. Saliva is a watery fluid released by the salivary glands into the mouth. It is about 99.5% water and also contains electrolytes, mucus, white blood cells, epithelial cells, enzymes, and antimicrobial agents. The enzymes in saliva begin...

anatomy of the intestines

Small and Large Intestine Functions

The small and large intestines complete digestion and absorb nutrients, water, and electrolytes. They are two structurally distinct organs with different shapes and jobs. Together, they move food material from the stomach toward elimination. The small intestine is about 7 meters long and has an inner diameter of only 2.5 cm. Most nutrient absorption happens here, so its inner lining is highly folded and covered with villi, which are finger-like projections. Each villus contains hundreds of...

accessory organs

Digestive Glands and Enzymes

Digestive glands and accessory organs help break down food even though food does not pass through them. They add enzymes and other fluids to the digestive tract to support digestion. The salivary glands release saliva, a fluid that contains water, mucus, and amylase. Amylase is a digestive enzyme that starts breaking down starches and other carbohydrates before food reaches the stomach. The liver, gallbladder, and pancreas also support digestion. They send their secretions into the duodenum,...

carbohydrate digestion

Carbohydrate Breakdown in the Digestive Tract

Carbohydrate digestion breaks food carbohydrates into saccharides, or sugars, that the body can use for energy. It begins in the mouth during mastication, which means chewing. The masticated carbohydrates then pass through the stomach without being broken down further. Digestion starts again in the duodenum, the first part of the small intestine. There, pancreatic alpha-amylase and brush border enzymes on the microvilli help convert complex carbohydrates into monosaccharides. These simple...

protein digestion

Protein Breakdown and Amino Acid Use

Protein digestion starts in the stomach, where strong acid helps unfold protein structure and expose peptide bonds in polypeptide chains. Digestive enzymes then begin breaking those chains into smaller pieces that can be processed by the body. Pepsin is a protease, which means it is a protein-digesting enzyme. It is made in the stomach and works with chymotrypsin and trypsin, enzymes released in the small intestine. These enzymes cut specific links between amino acids and form shorter...

lipid digestion

Lipases and bile help the body break down lipids, which are large molecules that do not mix well with water. Because most digestive enzymes are water-based, lipids need special steps before the body can use them. Lingual lipase is an enzyme made by acinar cells in the sublingual gland. It is found in saliva, but it has only a small role in the mouth. Its best pH, or acidity level, is 3.5-6.0, so it becomes active after chewed food reaches the acidic stomach. Gastric lipase is another acidic...

neural regulation

Brain and Gut Control of Digestion

Brain and gut control digestion through a cephalic phase and the enteric nervous system. The cephalic phase begins when the brain sees or smells food. It sends impulses through cranial nerves to the salivary glands and stomach so the body is ready to eat. This first response is a conditioned, or learned, reaction to familiar foods. Appetite also changes the response. People may make more saliva and hear more stomach rumbling when they think about apple pie than broccoli. The hypothalamus and...

hormonal regulation

Digestive Hormones and Stomach Control

Digestive hormones control when the stomach makes acid and when food moves into the small intestine. They work with the neuroendocrine system, which links nerve signals and hormone release during digestion. In the stomach, proteins are detected by sensory neurons in the enteric nervous system. This stimulates the pyloric gland to release gastrin. Gastrin then helps trigger histamine release, and together they start hydrochloric acid production. The acid helps break food down into chyme. As the...

key terms and concepts

Learn how lingual lipase, gastric lipase, and bile help break down fats. See how emulsification in the duodenum increases surface area for digestion.

Lipases and Bile in Fat Breakdown | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

Next Generation Science Standards

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Life Science

HS-LS1-2

Florida Department of Education

SC.912.L.14

SC.912.L.14.46

new-york-state-science-learning-standards

New York State Science Learning Standards

Structure and Function

HS-LS1-2.

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Lipases and Bile in Fat Breakdown

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