Biology Questions and Answers

(Greg DeLong) #1

Biology Questions and Answers


Monosaccharides, amino acids, mineral


salts and watintestinal epithelium aner are absorbed by thed collected by (^)
capillary vessels of the intestinal villi.
From the capillaries,mesenteric circulation, a nutrients go to thesystem of
vessels that drains the intestinal loops.
The blood of the mesenteis drained to the portal heric circulationpatic vein and (^)
some nutrients are processed by the
liver. From thgathered by the hepatic veins thate liver, nutrients are (^)
discharge its blood content into the
inferior vena cava.inferior vena cava then gains the right Blood from the (^)
chambers of the heart anthe lungs for oxygenation. From d is pumped tothe
lungs the blood then returns to the
heart where it is pumped to the tissuesdistributing nutrients and oxygen.



  1. What is the special route
    that lipids follow during
    digestion? What are
    chylomicrons?


Triglyceridwithin micelles sufes emulsified bfer the action y the bileof
lipases that break them into fatty acids
and glycerol. Fattycholesterol are absor acids, glycerol abed by the nd
intestinal mucosa. In the interior of the


mucosal cells fatty acids anform again triglycerides that togd glyceetherrol (^)
with cholesterol and phospholipids are
packed proteins ain smallnd called chylomicro vesicles covered byns. The (^)
chylomicrons are released in minuscule
lymphatic vessels not in blood vesselsand they gain the lymphatic circulation. (^)
So the lymphatic system plays an
important rollipids. e in the absorption of
The lymphatic circulation drains its
content to thIn that manner chylomicroe venous blood circulation.ns reach the
liver where their lipid content is
processeunder the form of protein-containind and released in the bloodg (^)
complexes called lipoproteins, like HDL,
VLDL and LDL.



  1. What are the so-called
    “good” and “bad” cholesterol?


Lipoproteins are complexlipids (triglycerides and cholesterol) anes made of (^) d
proteins. The lipoproteins present
different densities according relationship between their protein ato the (^) nd
lipid quantities since lipids are less
dense than proteins. Low-dlipoproteins (LDL) are those ensitywith a low (^)
protein/lipid rlipoproteins (Helation; hDL) have a highigh-density
protein/lipid relation; another group is
the very low-dwith very low protein/lipid ensity lipoproteins (VLDL)relation.
LDL is knbecause it transportsown as “bad cholesterol” cholesterol from (^)
the liver to the tissues and so induces
the formation oinside blood vessels, a cof atheroma pndition callelaques (^) d
atherosclerosis (do not confuse with
arteriosclerosis)circulatory obstructions like that can lead to severeacute
myocardial infarction, cerebrovascular
accidents and thrombas “good cholesterol” since it transposis. HDL is knownorts
cholesterol from the tissues to the liver
(to be eliminateelevation of the HDL blood level reducesd with the bile) and (^)
the risk oftransforms into LDL aft atherosclerosis.er losin (VLDLg
triglycerides in the blood).
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