Welcome to this lesson on accessory organs. Today you are going to be taking a look at the pancreas, gallbladder and liver, and investigate their role in digestion. Specifically, you will look at:
The pancreas, gallbladder, and liver are identified as accessory organs. This means they play a role in digestion, but they're separate from the digestive tract.
As you move through the lesson, refer to the diagram below as a visual.
The pancreas, labeled in orange, is an organ that releases enzymes which help to break down carbohydrates, lipids, proteins, and nucleic acids within the small intestine. It also plays a role in regulating our blood sugar levels or homeostasis.
A person who has Type 1 or Type 2 diabetes have issues with their pancreas where they're not able to produce insulin, which helps to regulate blood sugar levels.
The pancreas releases enzymes that help break down these materials in in digestion and these pancreatic juices also help to neutralize the acids in chyme. Chyme is a very acidic substance from the stomach and it is very important to neutralize its pH to make it easier on the lining of the small intestine as it passes through it.
The liver, labeled in red, produces bile. Bile is the substance that aids in the digestion and absorption of fats.
In addition to producing bile for digestion, the liver actually has many different roles in the body. Some of them are digestive-related, and some of them aren't. Some other functions of the liver include: stores vitamins and minerals, stores glucose as glycogen, and helps remove toxins such as alcohol from the blood.
It's related to the hepatic portal system, which is a system of blood vessels that diverts blood from the small intestine to the liver.
What happens is nutrient-rich blood is delivered from the small intestine, through the hepatic portal system, up to the liver. From there, nutrients that are in that blood from digestion are either processed, stored, or can be used for synthesis of proteins or by cells to make ATP. The liver will determine what needs to happen with these substances based on our metabolic needs.
If there is too much glucose in that blood that's delivered to the liver, it will store some of that glucose as glycogen. If there's a certain vitamin or mineral that happens to be really high in the blood at that time, it can also store some of those extra vitamins and minerals, such as iron in the liver until it's needed later, as well.
The gallbladder, labeled in green, stores bile and releases it into the small intestine when needed. Bile is produced in the liver but stored in the gallbladder. So when bile is needed-- if there are fats that need to be digested or absorbed-- the gallbladder will release some of this bile through the bile ducts into the small intestine.
This lesson has been an overview of the accessory organs. Specifically, you looked at the structure and function of the pancreas, gallbladder and liver.
Keep up the learning and have a great day!
Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND
A mixed organ (both endocrine and exocrine) that produces and secretes pancreatic juices into the small intestine that aid in the digestion of food.
The largest of the visceral organs, the liver produces bile and secretes it into the gallbladder to be stored. The liver also processes nutrients such as amino acids and carbohydrates and also “detoxifies” the blood.
A secretion created by the liver that is used to aid in the digestion of lipids (fats).
The organ that stores bile until we need to secrete it; bile is transported from the gallbladder into the duodenum through bile ducts.
A system of veins that drain blood from the stomach and intestines to the liver; a portal system consists of two consecutive capillary beds connected by a portal vein(s).