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

Im Mund beginnt die Lipidverdauung, wenn die Dr&#xFC;sen der Zunge linguale Lipase freisetzen, ein Enzym, das den Prozess des Abbaus gro&#xDF;er Fette wie Triglyceride, die am h&#xE4;ufigsten in der Ern&#xE4;hrung vorkommen, in Gang setzt.
 W&#xE4;hrend die Lipide in Richtung Magen wandern, werden zus&#xE4;tzliche Enzyme, Magenlipasen, ausgeschieden.
 Da Lipide hydrophob sind, neigen sie dazu, sich in diesen w&#xE4;ssrigen Umgebungen zu aggregieren, was verhindert, dass diese Lipasen die Massen abbauen.
 Sobald sie sich im Zw&#xF6;lffingerdarm befinden, beschichten Gallensalze die Fetttropfen und bewirken, dass sich die K&#xFC;gelchen verteilen und eine Emulsion und eine w&#xE4;ssrige Suspension bilden.
 Bei vergr&#xF6;&#xDF;erter Oberfl&#xE4;che k&#xF6;nnen die vorhandenen Lipasen der Bauchspeicheldr&#xFC;se die Triglyceride in kleinere Komponenten, n&#xE4;mlich freie Fetts&#xE4;uren und Monoglyceride, hydrolysieren.
 Diese kleineren Produkte sind nun bereit, vom D&#xFC;nndarm zur weiteren Verarbeitung aufgenommen zu werden.

Wang, Tony Y., Min Liu, Piero Portincasa und David Q.-H. Wang. "Neue Einblicke in den molekularen Mechanismus der intestinalen Fettsäureabsorption." European Journal of Clinical Investigation 43, Nr. 11 (November 2013): 1203–23. [<a href="https://doi.org/10.1111/eci.12161" target="__blank">Quelltext</a>]

verdauung der lipide

Lipide sind gro&#xDF;e Molek&#xFC;le, die in der Regel nicht wasserl&#xF6;slich sind. Da die meisten Verdauungsenzyme des menschlichen K&#xF6;rpers auf Wasser basieren, muss der K&#xF6;rper bestimmte Schritte durchf&#xFC;hren, um Lipide abzubauen und zur Verf&#xFC;gung zu stellen.
 
 <h4>Die linguale Lipase und gastrische Lipase</h4>
 
 Die linguale Lipase ist ein Enzym, das von den Azinuszellen der Unterzungenspeicheldr&#xFC;se abgesondert wird und die Lipidverdauung unterst&#xFC;tzt. Es ist zwar im Speichel vorhanden, spielt aber nur eine minimale Rolle beim Lipidabbau im Mund. Interessanterweise hat die linguale Lipase ein pH-Optimum von 3,5-6,0 und wird erst aktiviert, wenn die gekaute Nahrung in das saure Milieu des Magens gelangt. Die gastrische Lipase ist eine saure Lipase, die von den gastrischen Hauptzellen in der Magenschleimhaut abgesondert wird.
 
 <h4>Saure Lipasen bei erwachsenen Menschen und Neugeborenen</h4>
 
 Die linguale Lipase und die gastrische Lipase umfassen die beiden sauren Lipasen, die im menschlichen Verdauungssystem vorkommen. Diese Lipasen sind im Magen aktiv, werden aber schnell durch die Gallens&#xE4;uren im Zw&#xF6;lffingerdarm inaktiviert. Die gastrische Lipase und linguale Lipase sind gemeinsam f&#xFC;r 10-30% der gesamten Lipidhydrolyse des menschlichen Erwachsenen verantwortlich, wobei die gastrische Lipase dabei den gr&#xF6;&#xDF;ten Beitrag leistet. Aufgrund der niedrigen Konzentrationen der Pankreaslipase und Gallensalzen in Neugeborenen, sind die sauren Lipasen f&#xFC;r die Lipidverdauung kritisch und machen etwa 50% der Lipidhydrolyse in Neugeborenen aus.
 
 <h4>Die Galle</h4>
 
 Die Galle enth&#xE4;lt Gallensalze, Lecithin und von Cholesterin abgeleitete Stoffe, wirkt also als Emulgator im Zw&#xF6;lffingerdarm des D&#xFC;nndarms. Die Emulgierung der Fetttr&#xF6;pfchen im Zw&#xF6;lffingerdarm vergr&#xF6;&#xDF;ert ihre Oberfl&#xE4;che um das Tausendfache und macht sie damit f&#xFC;r die Pankreaslipasen besser zug&#xE4;nglich.

Verdauung der Lipide

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

Lehre

JoVE Core

Biology

Biologie

Genetics

Genetik

Nutrition and Digestion

Ernährung und Verdauung

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

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.

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Die JoVE-Serie erweckt die Biologie durch über 300 prägnante und leicht verständliche animierte Video-Lektionen zum Leben, die Schlüsselkonzepte der Biologie erklären, sowie durch mehr als 150 Videos von Wissenschaftlern in der Praxis, die aktuelle Forschungsexperimente in den Labors von heute zeigen.

Next Generation Science Standards

High School

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.

structural-organization-of-the-human-body-an-overview

Structural Organization of the Human Body: An Overview

It is convenient to consider the body&#39;s structures in terms of fundamental levels of organization that increase in complexity: subatomic particles, ...

Tissues

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Cells with similar structure and function are grouped into tissues. A group of tissues with a specialized function is called an organ. There are four main ...

Mitochondria

The Endoplasmic Reticulum

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1. Obtain, evaluate, and communicate information to explain how differences in cellular structure (mitochondria, cytoskeletal structure, endoplasmic reticulum, cell membrane) lead to differences in the function and organization of the four tissue types (epithelial, connective, muscular, and nervous).

9-12.HA.1.1

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Cells of the Epidermis

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Accessory Structures of the Skin: Sweat Glands

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Accessory Structures of the Skin: Hair and Hair Follicles

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Accessory Structures of the Skin: Nails

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2. Obtain, evaluate, and communicate information to describe how the structures of the integumentary system and its accessory organs contribute to its function. Examples: how the layers of the skin contribute to homeostasis, the role of glands in thermoregulation and in hydration of skin and mucous membranes, the protective functions of hair and nails

9-12.HA.1.2

Thermoregulation

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...

a. Construct an explanation of the relationships between the integumentary system and other organ systems, including the body's mechanisms for maintaining homeostasis. Examples: Explain how changes in vessel diameter and evaporation of water over the skin contribute to thermoregulation (cardiovascular). Explain how sweat is used to excrete nitrogenous waste from the blood (cardiovascular). Explain how the skin and mucous membranes create a barrier against infection (immune system).

9-12.HA.1.2.a

Introduction to the Skeletal System

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Components ...

Classification of Bones

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Joints

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3. Develop and use a model to illustrate how the structures of the skeletal system contribute to its function. Examples: Create a diagram or 3D model to illustrate bone shape, joint types, and bones in the appendicular and axial skeletons. Use models to illustrate the role of the skeletal system in movements around joints, support of a body structure, and protection of soft tissues.

9-12.HA.1.3

bone-formation-by-endochondral-ossification

Bone Formation by Endochondral Ossification

Bone formation, or ossification, begins around the sixth to seventh week of embryonic development. Most bones develop from a cartilaginous template ...

bone-formation-by-intramembranous-ossification

Bone Formation by Intramembranous Ossification

Intramembranous ossification is one of the two processes involved in the development of bones within an embryo. The flat bones of the face, most of the ...

Bone Remodeling and Repair

a. Obtain, evaluate, and communicate information describing the growth and development of the skeletal system.

9-12.HA.1.3.a

The Functions of the Skeletal System

The most apparent functions of the skeletal system are support, protection, and movement. However, bone tissue also performs several other critical ...

Skeleton and Calcium Homeostasis

Calcium is not only the most abundant mineral in bone but also the most abundant mineral in the human body. Calcium ions are needed for bone ...

The Bone Matrix

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Overview of Hematopoiesis

Hematopoiesis, or hemopoiesis, is the production of the formed elements in blood from common progenitors, called hematopoietic stem cells, or HSCs.
During ...

b. Construct an explanation of the relationships between the skeletal system and other organ systems, including the body's mechanisms for maintaining homeostasis. Examples: Explain the role of spongy bone in hematopoiesis (cardiovascular system) and leukopoiesis (immune system). Explain how the storage of minerals in bone contributes to homeostasis.

9-12.HA.1.3.b

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Naming Skeletal Muscles

Skeletal muscle names are based on various factors, such as location, physical traits, and functions.
Often, muscle names indicate their location. For ...

Muscle Coordination and Action

The skeletal muscles can coordinate, oppose, or assist each other to facilitate voluntary body movements.
Depending on their function, a muscle or group ...

Fascicle Arrangement in Skeletal Muscles

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4. Develop and build a three-dimensional model to illustrate the structures of the muscular system, including muscle locations, origins, and insertions, and explain their roles in movement and support. Example: Design and build a model of a lever to illustrate the relationship between bones and muscles and explain their roles in body movement and support.

9-12.HA.1.4

Microscopic Anatomy of Skeletal Muscles

Each skeletal muscle is composed of multiple bundles of elongated multinucleated muscle cells or muscle fibers.
These cells are enclosed by a plasma ...

The Sarcomere

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excitation-contraction-coupling-in-skeletal-muscles

Excitation-Contraction Coupling in Skeletal Muscles

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Relaxation of Skeletal Muscles

The period of muscle contraction primarily influences the duration of stimulation at the neuromuscular junction (NMJ), the presence of free calcium ions ...

a. Model the cellular physiology of skeletal muscle, including how the cell functions in muscle contraction and relaxation. Example: Use straws and paper to create a model of a sarcomere to illustrate how the fibers move during contraction and relaxation.

9-12.HA.1.4.a

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Muscle Stimulation Frequency

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b. Obtain, evaluate, and communicate information to explain muscle fatigue and tone in terms of muscle cell physiology.

9-12.HA.1.4.b

Organization of the Nervous System

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The nervous system can be divided into two major categories&#8212;the ...

functional-divisions-of-the-nervous-system

Functional Divisions of the Nervous System

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peripheral-nervous-system-ganglia-and-nerves

Peripheral Nervous System: Ganglia and Nerves

The peripheral nervous system consists of nerves, ganglia, and sensory receptors.
Each nerve has an outermost connective tissue layer called the ...

5. Obtain, evaluate, and communicate information explaining the relationship between the structures and functions of the central nervous system and the peripheral nervous system.

9-12.HA.1.5

Action Potential

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Action Potential: Phases of Stimulation

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Voltage-gated Ion Channels

a. Use a model to illustrate the role of action potentials in neural transmission. Clarification: Discussions of sodium-potassium pumps and ion channels are not required.

9-12.HA.1.5.a

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b. Construct an explanation of the role of reflex arcs, the central nervous system, and special senses in the response to stimuli to maintain homeostasis and guide behavior. Example: smelling a strong odor initiating a sneeze response using a reflex arc; pupil diameter changing in relation to the amount of light entering the eye Clarification: Discussion of the anatomy and physiology of the sensory organs is not required.

9-12.HA.1.5.b

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The Synapse

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c. Construct an explanation of the role of neurotransmitters in the functions and behavior of the nervous system. Clarification: Discussion of classes of neurotransmitters is not required.

9-12.HA.1.5.c

Lipases and Bile in Fat Breakdown

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