I've read through my book and am having trouble understanding the chapter when they talk about the following topics can someone explain it to me thanks
How do lipids move
through the body so they can be digested and absorbed?
How are lipids stored in the
body?
http://au.answers.yahoo.com/question/index.php?qid=20070501141906AAkUhbE
To better understand how lipids move through the body, let's start by discussing the process of lipid digestion and absorption.
1. Digestion: When you consume foods that contain lipids (such as fats and oils), the digestion process begins in the stomach. However, the majority of lipid digestion occurs in the small intestine. The liver produces a substance called bile, which is stored in the gallbladder and released into the small intestine when lipids are present. Bile helps break down large lipid molecules into smaller droplets, a process called emulsification. This emulsification increases the surface area of lipids, making it easier for digestive enzymes called lipases to break them down further into smaller components like fatty acids and glycerol.
2. Absorption: Once the lipids are broken down into smaller components, they can be absorbed into the bloodstream. The small intestine is lined with finger-like projections called villi, which are covered in microvilli (tiny projections). These structures greatly increase the surface area available for absorption. The small lipid components, along with other nutrients, are absorbed into the cells lining the small intestine through diffusion and active transport mechanisms.
3. Transport: After absorption, lipids are reconstituted back into triglycerides (the main form of fat in the body) within the absorptive cells of the small intestine. These triglycerides, along with other lipids, cholesterol, and fat-soluble vitamins, are then combined with proteins to form lipoproteins. Lipoproteins transport lipids through the bloodstream because lipids are not water-soluble and cannot move freely.
Now, let's address how lipids are stored in the body:
Once absorbed, lipids are primarily stored in two ways:
1. Adipose tissue: Excess lipids are converted back into triglycerides and stored in specialized fat cells called adipocytes within adipose tissue. Adipose tissue serves as the main energy storage site in the body. When more energy is consumed than is needed, triglycerides are synthesized and stored in adipose tissue. When energy is required, these stored triglycerides are broken down again into fatty acids and glycerol to be used as fuel.
2. Other storage sites: Lipids can also be stored in other tissues and organs, such as the liver and muscle cells. In the liver, excess lipids are converted into triglycerides and stored until needed. Within muscle cells, lipids are stored in structures called lipid droplets, which can serve as an energy source during prolonged physical activity.
I hope this explanation clarifies how lipids move through the body, get digested, absorbed, and stored. If you have any further questions, feel free to ask!