Name: digestive glands and enzymes
Uploaded: 2026-08-26T08:20:11.781Z
Duration: 1 min 58 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

Accessory Organs

- [Instructeur] Bijkomende spijsverteringsorganen scheiden enzymen en andere stoffen af in het primaire spijsverteringskanaal om de spijsvertering te vergemakkelijken.
 De eerste daarvan zijn de speekselklieren in de mond die amylase afscheiden.
 Dit enzym begint met de afbraak van zetmeel en andere koolhydraten.
De overige organen scheiden spijsverteringsenzymen af in de twaalfvingerige darm, waar de meeste vertering plaatsvindt.
 De lever en de galblaas werken samen om gal te verdelen, een stof die door de lever wordt geproduceerd, maar door de galblaas wordt opgeslagen en afgegeven.
 Gal is een mengsel van water, galzouten, cholesterol en bilirubine, een afvalproduct van hemoglobine afbraak.
Galzouten zijn zowel hydrofoob als hydrofiel, wat helpt om grote vetbolletjes te emulgeren tot kleinere.
 Lipase uit de alvleesklier kan dan de voedingsvetten hydrolyseren tot vetzuren en glyceriden.
 De extra alvleesklierenzymen, trypsine en chymotrypsine, verdelen prote&#xEF;nen in peptiden die door carboxypeptidase in aminozuren worden gekataboliseerd.
Amylase, dat koolhydraten verteert, komt ook vrij door de alvleesklier.
 Ten slotte scheidt de alvleesklier bicarbonaat af in de twaalfvingerige darm om het chymus, een mengsel van voedsel en maagzuur, te neutraliseren en darmen te beschermen tegen de zuurgraad.

hulporganen van het spijsverteringsstelsel

Hulporganen van het spijsverteringsstelsel zijn organen die deelnemen aan de vertering van voedsel, maar er niet rechtstreeks mee in contact komen, in tegenstelling tot de mond, maag of darm. Hulporganen van het spijsverteringsstelsel scheiden spijsverteringssappen af in het spijsverteringskanaal om de afbraak van voedsel te bevorderen.
Speekselklieren
Speekselklieren scheiden speeksel af&#x2014;een complexe vloeistof die onder andere water, slijm en amylase bevat. Amylase is een spijsverteringsenzym dat al begint met het afbreken van zetmeel en andere koolhydraten voordat deze de maag bereiken.
Lever, galblaas en alvleesklier
De lever, galblaas en alvleesklier zijn de andere hulporganen die bij de spijsvertering betrokken zijn. De lever en galblaas scheiden gal af, terwijl de alvleesklier via de alvleeskliergang spijsverteringsenzymen afscheidt in de twaalfvingerige darm. De lever en galblaas werken samen om gal af te geven aan de twaalfvingerige darm. De lever produceert gal, maar deze wordt opgeslagen in de galblaas om zo nodig te worden afgescheiden.
Gal is een mengsel van water, galzouten, cholesterol en bilirubine. Galzouten bevatten hydrofobe gebieden en hydrofiele gebieden, waardoor ze zowel met vetten als met water kunnen interageren. Zo breken ze grote vetdruppels af tot kleinere&#x2014;een proces dat emulgering wordt genoemd. Bilirubine is een afvalproduct dat ontstaat wanneer de lever hemoglobine afbreekt uit rode bloedcellen. De globine en het ijzer worden hergebruikt, terwijl het heem wordt omgezet in bilirubine en via de gal wordt uitgescheiden. De aanwezigheid van bilirubine geeft ontlasting haar bruine kleur.
Galstenen zijn ophopingen van galbestanddelen die zich in de galblaas of de ermee verbonden galwegen vormen. Cholesterolstenen bestaan voornamelijk uit cholesterol in de gal. Pigmentstenen worden gevormd uit bilirubine. De meeste stenen ontstaan ongemerkt; als een steen echter vast komt te zitten in de galweg, kunnen ernstige symptomen optreden, zoals ontsteking van de galblaas of alvleesklier, koorts, braken en geelzucht. Een cholecystectomie&#x2014;het verwijderen van de galblaas&#x2014;is de voornaamste behandeling, en de verwijdering ervan heeft slechts geringe langetermijnbijwerkingen.
Alvleesklier
De alvleesklier scheidt verschillende enzymen af. Lipase breekt triglyceriden af tot vetzuren en monoglyceriden. Trypsine en chymotrypsine kataboliseren eiwitten tot peptiden. Carboxypeptidase breekt deze peptiden vervolgens af tot afzonderlijke aminozuren. De alvleesklier geeft ook amylase af om eventueel resterende koolhydraten te verteren.

Hulporganen van het spijsverteringsstelsel

Accessory organs are those that participate in the digestion of food but do not come into direct contact with it like the mouth, stomach, or intestine do. ...

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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

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, the first part of the small intestine, through channels called the biliary tree. The liver makes bile, and the gallbladder stores it until it is needed.

Bile is made of water, bile salts, cholesterol, and bilirubin. Bile salts have both hydrophobic and hydrophilic regions, so they can interact with fat and water. This lets bile emulsify large fat globules into smaller droplets. Bilirubin is a waste product that forms when the liver breaks down hemoglobin from red blood cells. The globin is recycled, and the heme, which contains iron, leaves the body in bile. Bilirubin also gives feces its brown color.

Gallstones are bile masses that can form in the gallbladder or in nearby bile ducts. Cholesterol stones are made mostly of cholesterol from bile, while pigment stones contain bilirubin. Many stones cause no symptoms, but a stone that blocks a bile duct can lead to serious problems such as gallbladder or pancreas inflammation, fever, vomiting, and jaundice. The main treatment is cholecystectomy, which is the removal of the gallbladder, and it usually has few long-term side effects.

The pancreas releases several enzymes into the small intestine. Lipase breaks smaller fat droplets into fatty acids and triglycerides. Trypsin and chymotrypsin break proteins into peptides, and carboxypeptidase breaks those peptides into individual amino acids. The pancreas also releases amylase to digest any remaining carbohydrates.

Digestive Glands and Enzymes

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 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 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...

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 the salivary glands, liver, gallbladder, and pancreas add enzymes and bile to digest carbohydrates, fats, and proteins.

Digestive Glands and Enzymes | 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.14.45

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New York State Science Learning Standards

Structure and Function

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Digestive Glands and Enzymes

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