Question

Trace the path ofa molecule of lipid from the point of ingestion until it reaches the lumen of the right atrium of the heart (in circulation). Describe the anatomical structures this molecule passes on its journey (alimentary canal organs/regions/structures, accessory organs, valves, epithelial tissues, relevant transport vessels it passes through)

Answer 1

Almost entire portion of fat in the diet consists of triglycerides which are made of three fatty acid molecules and a single glycerol molecule.The saliva contains no lipase however the gastric juice from stomach contains gastric lipase which convertd some fats into monoglycerides and fatty acids.Fat is largely digested in the small intestine and then bile salts breakdown fat droplets into small ones by reducing the surface tension of these fat droplets,this process is called emulsification.Lipase is present in Pancreatic juice and is largely the main digestive enzyme for fat.Intestinal lipase also helps in fat digestion.Finally all fats are converted into fatty acids,glycerol and monoglycerides.

And then fatty acids and glycerol and fat soluble vitamins are absorbed via simple diffusion.Fatty acids are insoluble in water and therefore are created into water soluble droplets called micelles with the help of bile salts and later are converted into chylomicrons and are released into intestinal cells into the lymph called lacteals.

After that fat is stored in fat deposits in the body and is readily available as source of fuel.

I have clubbed the two questions and answered them together.