Bile and Emulsification | Physiology | Biology | FuseSchool


YUM steak as soon as it enters my mouth

digestion begins I chew to break it down

into manageable chunks my tongue mixes

saliva into the beefy mix and off it

goes through my digestive system you

should already know about the digestive

system if not you may want to watch this

video first we've previously discovered

that different enzymes break down

different food molecules which is quite

important because we saw that digesting

lipids was a little more complicated and

required bile and emulsification to help

along the way which is what we're going

to look at in more detail in this video

before we start let's think about why we

choose to break up our food and why our

stomach muscles churn up the

semidigested mix it increases the

surface area for the enzymes to work on

thus speeding up the rate at which our

body can break down the food to extract

the energy from it that we require now

let's fast-forward to our stomach our

chewed up stomach churned food has a

large surface area and is mixed with the

stomach's gastric juices these are

watery and these together with the

watery saliva secretions of the oral

cavity mean that the food is now in

quite a watery solution this is called

quorum if you've ever added water to a

greasy pan after cooking you'll know

that water and fats and oils or lipids

don't mix too well you end up with oily

droplets pretty much the same thing

happens in our stomach our watery

mixture of quorum contains big globules

of fats and oils which won't be mixed

into the solution this is a problem

because it means that the lipids have a

small surface area for the lipid

digesting lipase enzymes to work on the

lipase enzymes are added in the small

intestine at the same time a special

substance called bile is also added to

the corium the bile increases the

surface area of the big fat globules by

breaking them up into smaller fat

droplets the increased surface area of

the lipid

oklets increases the rate of digestion

of lipids by the lipase enzymes because

more lipid is available for digestion at

any given time lipase enzymes can now

more quickly break the lipids up into

fatty acids and glycerol thanks to the

bile addition the process of increase in

the surface area of the lipids is called

emulsification the bile is produced in

the liver and stored in the gallbladder

it's released down the bile duct into

the small intestine from the gallbladder

not only does the bile increase the

surface area of the lipids it also has

another great quality its alkaline this

helps to neutralize the strong

hydrochloric acid which is added to the

quorum and provides a more optimum pH

for enzymes in the small intestine to

work in to end with a random fact the

bile is green in color and it's this

that makes your poop brown in this video

we've learned that bile is produced in

the liver and stored in the gallbladder

from here it's released down the bile

duct into the small intestine where it

divides big globules of lipids into

smaller droplets this increases the

surface area of lipids available for the

lipid digesting lipase enzymes to work

on if you liked the video give it a

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comment below if you have any questions

why not check out our first graph as

well until next time