Large Intestine | Colon

hi Ron dr. Mike here in this video we're

gonna take a look at the large

intestines large intestines is only

around about 1.5 meters long and you'll

find that the small intestines lead to

the large intestines so they're not

longer than the small intestines but

they are wider now I've drawn up an

image here highlighting the large

intestines as you can see and the large

intestines are made up of the cecum the

appendix the a sending colon the

transverse colon the descending colon

the sigmoid colon the rectum and then

the anus now what you'll find is

something we've spoken about before

spoken about the liver sitting in this

upper right quadrant here then you can

see we've got the duodenum remember

that's the first part of the small

intestines this C shaped duodenum you

can see that here's the first portion

and the second portion and the third

portion and then the fourth portion is

here which means the rest of the small

intestines the ileum and the jejunum

jejunum and ileum will be sitting right

here in this window so you can see that

large intestines frame the small

intestines now it goes from the duodenum

to the jejunum and then the ileum and

this is where the ileum finishes at the

ileocecal valve so goes from ileum to

seek him now the cecum is this blind

ended pouch couple centimeters long and

wide and it's quite small for humans but

for other animals like rats or even cows

the cecum is quite large and the reason

why is because the cecum evolutionarily

is there for us to be able to help

digest indigestible foodstuffs often in

digestibility being grasses for example

and what you'll find is if you open up

the stomach of a cow or even a rat

you'll find the cecum is huge because

it's storing all these different

macromolecules and trying to digest it

how is it digesting it well it's

utilizing enzymes but also utilizing the

bacteria that's present in the vermiform

appendix which is the little worm and

the little worm is around about the size

of the finger maybe a little bit smaller

and what you'll find is we think that it

is one of those vestigial organs meaning

we can chop it off get rid of it it's

not a problem that's true but it doesn't

mean it doesn't play a role the role

that the appendix plays is that of


the gut when we've lost our gut flora so

this may mean due to some sort of

gastrointestinal upset you've may have

had significant bouts of diarrhea or

even had significant amounts of

antibiotics this may have killed off

your gut flora the vermiform appendix

plays an important role in squirting out

more bacteria to help repopulate your

gut that's so that's quite important so

guys from the cecum then to the a

sending : now your what you'll find is

that the a sending column sitting behind

here is going to be our right kidney

then we've got the transverse colon and

then behind here is going to be the left

kidney and then we'll get the descending

colon to the rectum and then it's got

sigmoid colon rectum and then anus now

you can see that the cecum is sitting at

the letter right iliac crest and or at

least the iliac fossa so that's going to

be part of that hip bone right and then

you can see the sigmoid colon sits in

the left iliac fossa now if we look at

the appendix how can you identify the

appendix we know it's it's somewhere in

this bottom right area how do we

identify it there's something called

McBurney's point no McBurney's point is

you take the anterior superior iliac

spine so this is this part here and take

your umbilicus which is your belly

button and you go two-thirds of the way

in between so around about there and

that is going to be where your appendix

it's and again that's called McBurney's

point all right if we have a look

superiorly you can see you get the

pancreas and you can see the tail of the

pancreas it's within the spleen we're

going to liver up here and you've got

the abdominal aorta where it's branching

and then you get the vena cava as well

all right let's go and have a look at

the tube the large intestines as a

hollow tube its function is

predominately there for absorption of

water and production of fecal material

and pushing along that fecal material

you can see a couple of things first

thing is that there's these what look

like pouches that are formed along the

large intestines they're called Hofstra

and they're circulations circulations is

because big long tube this big long tube

has three longitudinal muscle groups

called NEA coli running the length of

them and this tenia coli the

longitudinal muscle is actually shorter

than the length of the two

which means it forms these circulations

or bunching up corn Hofstra what's the

function of these hosta or they helped

push material through under peristalsis

again the tenure coli what that does is

produce the Hofstra and help produce

peristalsis you can see that you've got

these what look like fat deposits called

epiploic appendices and they are

basically peritoneum filled up with fat

why they there we don't actually know we

know they can become inflamed and the

symptoms are very similar to that of

appendicitis so what we've got is

basically a quick summary of the anatomy

of the large intestines and also what's

going on at the tube of the large