Date post: | 16-Jul-2015 |
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CONTENTS
• Etymology
• Definition
• Structure
• Size
• Origin
• Life cycle
• Transportation
• Importance
• Chylomicron retention disease
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ETYMOLOGY OF CHYLOMICRON
The word "chylomicron" has been derived
from two greek words:
• "Chylos“ means milky
• “Mikros" means small
• Chylomicrons= small milky (globules).
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DEFINITION
• A large plasma lipoprotein particle, occurring
as a droplet consisting primarily of
triglycerides and functioning in the transport
of neutral lipids from the intestine to the
tissues by way of the lymph.
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STRUCTURE OF CHYLOMICRONS
• Chylomicrons are considered large
lipoproteins because of lipid, phospholipid
and protein constituents.
• However, the Protein Constituents are
extremely low although their role in the
chylomicrons metabolism remains vital.
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CHYLOMICRON COMPONENTS
Triglycerides 85-92%
Phospholipids 6-12%
Cholesterol 1-3%
protein 1-2%
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SIZE OF CHYLOMICRONS
• According to Scientists, the diameter of these
particles can range from:
• 75 to 1200 nm
• 1200 nm would be largest at its production in
the intestinal cells.
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ORIGIN OF CHYLOMICRONS
• Chylomicrons are formed in the
endoplasmic reticulum of the mucosal
cells within the villi of the duodenum.
• Secreted through the baso-lateral
membrane into the lymphatic system.
• From the lymph to the blood systems
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LIFE CYCLE OF CHYLOMICRONS
Life cycle of chylomicrons consist of three
stages that differ in the constituency of
chylomicrons because some of the protein in
the form of Apolipoprotein will enter the
chylomicron particles as it reaches its
destination via the circulation.
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STAGES OF LIFE CYCLE
The Life Cycle of Chylomicrons can be
illustrated as having three distinct stages.
These stages include:
• The Nascent Chylomicrons
• The Mature Chylomicrons
• The Remnant Chylomicrons
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NASCENT CHYLOMICRONS
• initial form
• formed in the intestinal epithelial cells or
inside the enterocytes.
• released by exocytosis
• central lacteal of vessels to blood via thoracic
duct
• They contain mainly Triglycirides , Cholestrol,
Phospholipids and Apolipoprotien B-48
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MATURE CHYLOMICRONS
• HDL donates apolipoprotein C2 and
apolipoprotein E to the nascent chylomicron,
and convert it to into mature chylomicron.
• Apolipoprotien C2 is the co-factor for
lipoprotien lipase activity.
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REMNANT CHYLOMICRONS
• Once the store of triglycerides become low,the
chylomicron donates it’s Apolipoprotienc2
back to the HDL know it is called remnant
chylomicron
• much smaller in size
• Apolipoprotien B-48 and Apolipoprotien E
• break down via endocytosis
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TRANSPORTATION OF FATS
• CCK will travel into the blood stream reach
the galblader
• Galblader contraction cause the fat to enter
into the bile.
• The bile will the travel down through bile duct
into the duedenum .
• The bile is going to emulsify the fat turn into
small droplets so that it could be absorb.
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CONTINUED…..
• Enter into the enterocytes
• The fat and the cholestrol will be packed into
chylomicron.
• Released from the basal lateral site of
enterocyte.
• Chylomicron will go into the lacteal
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CONTINUED…..
• From lacteal it will travel into the thoracic
duct.
• The chylomicrom will enter into the
circulatory system .
• In blood stream they going to contain two
new Apo Protien :
• Apo C and Apo E
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• When chylomicron
enter into the liver
• APO-E will bind
with the LDL-R
• Chylomicron will
take up by the liver
• And triglycirides
are use by the liver
TRANSPORT OF FATS TO LIVER
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TRANSPORT OF FATS TO ADIPOSE
TISSUE
• Adipose is made up of lipocytes.
• They express the emzye called lipoprotien
lipase.
• Chylomicron will bind to the lipoprotien of
lipase through apo-c
• enzyme is going to cleave the triglycirides into
indidvidual fatty acid and glycerols.
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CONTINUED…..
• Then they absorb into the fats cells.
• The amount of the triglycerides is low
• Chylomicron will lose the APO-C
because of the less amount of
triglycerides.
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IMPORTANCE OF CHYLOMICRONS
• Lipid metabolism
• Fatty nutrients circulation and absorption in
the intestinal cells
• Gather proteins and cholesterols from the
lymphatic system.
• Supply triglycerides and cholesterols to
tissues
11/20/2014 25
CHYLOMICRON RETENTION
DISEASE
• Chylomicron retention disease is a rare
disease.
• It's an inherited disorder that affects the
absorption of dietary fats, cholesterol, and
certain fat-soluble vitamins.
• A lack of chylomicron transport causes
severely decreased absorption (malabsorption)
of dietary fats and fat-soluble vitamins.
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SYMPTOMS
• The signs and symptoms of chylomicron
retention disease appear in the first few
months of life.
• They can include failure to gain weight
• Failure to grow at the expected rate
• Diarrhea
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