myelin sheath

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Transcript myelin sheath

Score: 50% (Exam 30%Report 20%)
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Office hour: 9-10 Tu, Th
Percent Fatty Acid Present in Triglycerides
Fat or Oil
Saturated
Unsaturated
Palmitic
Stearic
Oleic
Linoleic
Animal Origin
Butter
29
9
27
4
Lard
30
18
41
6
Beef
32
25
38
3
Vegatable Origin
Corn oil
10
4
34
48
Soybean
7
3
25
56
Peanut
7
5
60
21
Olive
6
4
83
7
Which fat or oil contains the most double bonds?
Which fats or oils are likely to be liquids at room temperature?
Which fats or oils have the least amount of unsaturated fatty acids?
Other
31
5
2
4
9
7
-
Familiarize yourselves with structure and names of fatty acids
(see hand-out 1)
Wax
Carnuba
Beeswax
Spermacetic
WAXES
Alcohol
CH3(CH2)28CH2-OH
CH3(CH2)28CH2-OH
CH3(CH2)14CH2-OH
Fatty Acid
CH3(CH2)24COOH
CH3(CH2)14COOH
CH3(CH2)14COOH
There are two common phospholipids found
in the bilayer:
Lecithin contains the amino alcohol,
choline.
Cephalins contain the amino alcohols
serine or ethanolamine.
Sphingolipids are named after the spinx in Greek mythology, part woman and part lion, who devoured all who
could not answer her riddles.
Sphingolipids are a second type of lipid found in cell membranes, particularly nerve cells and brain tissues.
They do not contain glycerol, but retain the two alcohols with the middle position occupied by an amine.
The human brain and spinal cord is made up of gray and white regions. The white region is made of nerve
axons wrapped in a white lipid coating, the myelin sheath, which provides insulation to allow rapid conduction
of electrical signals. Multiple sclerosis caused by a gradual degradation of the myelin sheath.
Sphingomyleins are located throughout the body in nerve cell membranes. They make up about 25 % of the
lipids in the myelin sheath that surrounds and insulates cells of the central nervous system.
Glycolipids are complex lipids that contain carbohydrates. Cerebrosides are an example
which contain the sphingosine backbone attached to a fatty acid and a carbohydrate. The
carbohydrates are most often glucose or galactose. Those that contain several carbohydrates
are called gangliosides.
Glucocerebroside has the specific function to be in the cell membranes of macrophages,
(cells that protect the body by destroying foreign microorganisms. Galactocerebroside is
found almost exclusively in the membranes of brain cells.
Prostaglandins
-exist and are synthesized in virtually every cell of the body
-were first discovered and isolated from human semen in the 1930s by Ulf von Euler of Sweden
and because they had come from the prostate gland, he named them prostaglandins
-are like hormones in that they act as chemical messengers, but do not move to other sites, but
work right within the cells where they are synthesized
-are unsaturated carboxylic acids, consisting of of a 20 carbon skeleton that also contains a five
member ring. They are biochemically synthesized from the fatty acid, arachidonic acid.
Inflammatory response (production of pain and fever), Blood clots, Induction of Labor and other
reproductive processes, Inhibit acid synthesis and increase secretion of protective mucus in
the gastrointestinal tract, Increase blood flow in kidneys, Promote constriction of bronchi
associated with asthma.
Triacylglycerol = stored fat
Nut
Plam kernel
Castor oil
Seame
Sunflower seed
Soy
Palm fruit
Report of VLDL, LDL, HDL and essential PUFA
3-5 pages
Due: 12 November before class (definitely not after class)
5% (from 20% of the report points)