How our body uses fat
3 Main Sources of Energy:
GLYCOGEN
DIGESTION
GLUCOSE
FAT
Is a simple sugar used as a primmary energy source
It is used by direct ingestion, by digestion of complex sugars and conversion fo glycogen
Mechanical digestion
Goes first; mouth & stomach
Complex carbohydrate
Mainly stored in liver and muscles
Triglyceride: 3 fatty acids and a glycerol molecule
Body's primary long-term source of energy
Solid materials are broken down to release fat.
Fat droplets are formed.
TRANSPORT
Lipoproteins with a monolayer shell have a hydrophobic interior and the ones that have a bilayer have a hydrophilic interior
The surface of lipoprotein contains cholesterol molecules, apolipoproteins and phospholipids
There are many times of lipoproteins
Chylomicron
Chylomicron remnant
VLDL
LDL
HDL
It is released by the liver and contains fats and cholesterol. Fat is eventually turned in LDLs and the excess of cholesterol become HDLs
Bad cholesterol
Good cholesterol
Albumin
It is synthesized in the liver and is the most abundant protein in the blood
Each molecule can carry 7 fatty acids
It can be used as energy or for a conversion to other molecules
Fatty acids bending proteins (FABPs)
Transport fatty acids by encapsulating them
ENDOGENEUS FAT
It is stored mostly in the adipose tissue and the liver regulate the amount in circulation
Liver
Converts fats to sugars and back
Synthesizes many molecules
Absorbs and release fat and cholesterol
Storing fat
After the VLDs become LDLs, the fatty acids are then assembled into triglycerides for storage
Adipose tissue also converts glucose to triglycerides.
Burning fats
Between meals, fatty acids bind to albumin and this give energy to the body
Glycerol is also released and it is used for making glucose
The liver converts glycogen to glucose for producing the energy they need
Mariana Elisa: A01746056
Kenya Bautista García: A01731790
Summary
KETONE BODIES
This group of molecules include acetoacetate and D-ℬ-hydroxybutyrate
During starvation or fasting, acetyl-coenzyme A is overproduced as fatty acid are breaking down
Instead of being fed into the citric acid, some of this coenzymes are converted into ketone bodies in the liver.
During starvation ketone bodies become an importance source of energy to the brain
APA sources:
Satoshi, A. How the body uses fat. Retrieved on April 25th, from: http://media.hhmi.org/biointeractive/click/obesity_processing_fat/27.html
Fat droplets pass through the duodenum
and are absorbed in the small intestine.
Fat is transported to various organs (use/storage)
Bile acids are added to the mix.
Bile acids brake up fat droplets into smaller pieces. (emulsification)
Chemical digestion
Pancreatic digestive juices are added.
Pancreatic lipase, for example, digests triglycerides, converting them each into two fatty acids and a monoglyceride.
Abosption adn Packaging
Fatty acids and monoglycerides are absorved by microvilli, reassembled into triglycerides.
Triglycerides are packed into special particles called chylomicrons are released into lymphatic system and eventually enter the blood.
Chylomicrons activate lipoprotein lipase, which breaks down triglycerides for absorption.
Fat absorbed is stored and later burned for energy.
As triglycerides are removed, chylomicrons shrink in size and become chylomicron remnants, which are absorbed by the liver.
Liver: key organ in lipid metabolism
SUMMARY