Lipids Lecture 10-11 Flashcards
what is the importance of fats in the body?
energy fuel energy stores emergency reserve padding insulation cell membrance raw material
fats provide what percentage of the resting body’s energy and energy used to fuel muscular work
80 to 90 percent
what is the importance of fats in the food?
nutrients transport energy sensory appeal appetite texture satiety
what type of vitamins do fats carry?
fat soluble vitamins A,D,E, K along with phytochemicals and assist in their absorption
what is the body’s chief form of stored energy?
fats
how do fats protect the internal organs form shock?
by serving as a cushioning form inside the body cavity
what forms the major material of cell membrane?
fats
what is cholersterol’s role in the body?
it is the raw material for emulsifiers in bile for the digestion of fat.
what is the relationship between fats and cholesterol in the body?
fat is emulsified by bile in the small intestine
bile shuttles lipids across mucus layer of the digestive tract to the surface of cells
lipids are used to form lipoproteins, like HDL, LDL, VLDL
what is LDL?
transports cholesterol and other lipids to tissues for use
what is HDL?
transports cholesterol from body’s cells to liver for disposal
what is VLDL?
transports triglycerides and other lipids made in the liver to the bodys cells for their use
what is LDL made of?
more lipid, less protein
what is HDL made of?
less lipid, more protein
what is the difference between HDL and LDL?
LDL delivers cholesterol to the tissues; HDL scavenges excess cholesterol and other lipids from the tissues, transports them via the blood stream and deposits them in the liver for disposal
what happens when LDL cholesterol is too high?
it contributes to lipid buildup in tissues, like the linings of the arteries triggering inflammation and leading to heart disease.
LDL is smaller than HDL, T/F?
F, LDL is larger, lighter, and richer in cholesterol; HDL is smaller denser and packaged with more protein
how and when is fat used as fuel for the body?
Fat cells respond to the call for energy by dismantling stored fat molecules (triglycerides) and releasing fatty acids into the blood. Upon receiving these fatty acids, the energy-hungry cells break them down further into small fragments. Finally, each fat fragment is combined with a fragment derived from glucose, and the energy-releasing process continues, liberating energy, carbon dioxide, and water. The way to use more of the energy stored as body fat, then, is to create a greater demand for it in the tissues by decreasing the intake of food energy, by increasing the body’s expenditure of energy, or both.
what are the three classes of lipids?
Triglycerides, phospholipids, and sterols
what are triglycerides?
the chief form of fat in the diet and the major storage form of fat in the body, composed of a molecule of glycerol with three fatty acids attached
what are phospholipids?
glycerol, two fatty acids and a phosphorus molecule
○ Soluble in water and fat
○ Emulsifier (substance that mixes with both fat and H2O and permanently disperses the fat in the water, forming an emulsion
○ Structural and regulatory roles in the cells (phospholipid bilayer)
what are sterols?
ring of carbon, cholesterol roles in the body, plant sterols
- Cholesterol: cell membrane structure, not an essential nutrient.
- Other sterols include vitamin D( made from cholesterol) and steroid hormones (sex hormones).
- Plant sterols in foods inhibit cholesterol absorption (found in nuts, seeds, legumes,fruits and vegetables).
How are fats digested, absorbed, and excreted?
in the mouth and stomach: little fat digestion takes place
in the small intestine: digestive enzymes accomplish most fat digestion in the small intestine. There, bile emulsifies fat, making it available for enzyme action. The enzymes cleave triglycerides into free fatty acids, glycerols, and monoglycerides
at the intestinal lining:
the parts are absorbed by intestinal villi. Glycerol and short chain fatty acids enter directly into the bloodstream
the cells of the intestinal lining convert large lipid fragments, such as monoglycerides and long chain fatty acids, back into triglycerides and combine them with protein, forming chylomicrons (a type of lipoprotein) that travels in the lymph vessels to the bloodstream
in the large intestine:
a small amount of cholesterol trapped in fiber exits with the fiber
little fat digestion happens in the mouth and stomach, T/F?
True
what accomplishes most fat digestion in the small intestine?
digestive enzymes
what emulsifies fat?
bile
what is triglyceride cleaved into?
free fatty acids, glycerol, and monoglycerides
once in the intestinal lining, what absorbs the fats?
intestinal villi, so that glycerol and short chain fatty acids enter directly into the bloodstream
how are chylomicrons formed?
the cells of the intestinal lining convert large lipid fragments, such as monoglycerides and long chain fatty acids, back into triglycerides and combine them with protein
the digestive tract absorbs triglycerides with remarkable efficiency?
yes
how many of the fats are absorbed?
98%, very little fat is excreted by a healthy system
what are the two essential polyunsaturated fatty acids?
linoleic acid and linolenic acid
what is linoleic acid?
Omega-6 fatty acid, Arachidonic acid
what is linolenic acid?
Omega-3 family (DHA and EPA) Heart disease, cancer prevention, cell membranes, brain function and vision
what happens when you have deficient essential fatty acids?
produces skin abnormalities and poor wound healing. In infants, growth is retarded and vision is impaired.
what is an omega 6 fatty acid derived from linoleic acid?
arachidonic acid, this is then turnt into eicosanoids
what are eicosanoids?
biologically active compounds that regulate body functions
what are omega three fatty acids?
● Omega-3 fatty acids are found in the eyes and brain and are essential for normal growth, visual acuity, and cognitive development. Can also play an important role in the prevention and treatment of heart disease
what are omega six fatty acids
have conditionally essential nutrients (a nutrient that is normally nonessential but must be supplied by the diet in special circumstances when the need for it exceeds the body’s ability to produce it)
what are the benefits of omega 3 fatty acids? examples?
heart health, cancer prevention, cell membranes, brain function and vision; EPA and DHA, both synthesized from linolenic acid
what is arachidonic acid synthesized from?
linoleic acid
whats is a derivative of linoleic acid? is this omega 3 or omega 6 fatty acid?
arachidonic acid; omega six
what does an omega 3 eicosanoid do?
relaxes blood vessels and lowers blood pressure
what does an omega 6 eicosanoid do?
it constricts the vessels and increases the pressure
what happens when balance is achieved between EPA and arachidonic acid?
it promotes normal blood pressure
what are the roles of essential fatty acids?
a. ) Provide raw material for eicosanoids (signaling molecules)
b. ) Serve as structural and functional parts of cell membranes.
c. ) Contribute lipids to the brain and nerves.
d. ) Promote normal growth and vision
e. ) Maintain outer structures of the skin, thus protecting against water loss.
f. ) Help regulate genetic activities affecting metabolism
g. ) Participate in immune cell functions.
