Why is the small intestine so long
Small intestine and food absorption | Physiology | Biology | FuseSchool
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can you believe your digestive system is
as long as a bus yep
it's about nine meters long all wrapped
up inside your body a lot of things go
on in your digestive system not just
digestion what else do you think happens
digestion goes hand-in-hand with
absorption which happens in your small
intestine which is what we're going to
look at in this video
digestion is the breakdown of food from
large insoluble molecules into small
molecules which can be used by your body
digestion involves many organs before it
reaches the small intestine for more
information on the roles of these organs
in the digestive system watch this video
enzymes and other chemicals such as bile
break down food for more on the role of
enzymes and bile in digestion watch
these videos as they move through the
digestive system carbohydrates are
broken down into sugars proteins are
broken down into amino acids and fats
are broken down into fatty acids and
glycerol but the job of the digestive
system doesn't stop a digestion for our
body to make use of these small soluble
molecules we need to absorb them into
our bloodstream this happens in a small
intestine the small intestine is made up
of lots of tiny finger-like projections
called villi the villi increased the
surface area of the small intestine the
larger the surface area the more
absorption that can take place each
villus has a tiny blood vessel called a
capillary and another vessel called a
lac till the food molecule is passed
from the villi of the small intestine
into either the blood capillary or the
lacteal once absorbed into the blood
vessel in the small intestine the
digestive food molecules can then be
transported around the body to where
they are needed so why did those large
molecules need to be broken down in the
first place the small intestine is kind
of like a sieve it has small holes in it
small molecules are able to pass through
those holes or large molecules cannot so
carbohydrates proteins and fats
all too large to pass through the holes
in the small intestine but sugars amino
acids fatty acids and glycerol are all
small enough to pass through sugars and
amino acids pass through the holes into
the blood capillary while fatty acids
and glycerol pass into the lacteal of
the villi these small molecules move by
diffusion moving from a high to a low
concentration for example the small
intestine has a high concentration of
sugar molecules whereas the blood
supplying the small intestine has a low
concentration of sugar so the sugar
moves down its concentration gradient
from a high concentration in the small
intestine through the holes in the villi
into the blood capillary where it's in
low concentration sugar amino acids
fatty acids and glycerol or use
diffusion to move into the blood within
the small intestine so after digestion
breaks down large molecules into small
molecules absorption of the small
molecules happens inside our small
intestine by diffusion into the blood
vessels what an amazing system if you
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if you have any questions why not check
out our first graph as well until next
time
