CHYLOMICRONS

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PRESENTED BY

Nosheen Afzal (Bi141014)

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CONTENTS

• Etymology

• Definition

• Structure

• Size

• Origin

• Life cycle

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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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STRUCTURE OF CHYLOMICRON

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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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ANY QUESTION?

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