If the rollover above isn’t sufficient, here’s some help.
Running from mouth to anus through the middle of ourselves and our cats, the inside of the tube called the digestive tract is not inside the body where vital organs such as the kidneys and the heart reside. The gut wall acts as a barrier between outside and inside.
If a cat swallowed a little marble, it would travel inside that tube, move on through the digestive tract as through a marble run, and eventually get pooped out. The marble would not get inside the body itself, it is too large to fit through the 'gateways' of the gut wall to get into the body, it would remain inside that tube and pass out the other end in the poop.
The bladder would never see that marble, the marble would not exit in the urine. The bladder is inside the body and handles waste products from inside by dumping them into the urine. Poop is waste from the gut, outside the body itself.
This inside/outside business is vital to understanding gut health and constipation so please take a few extra seconds to imagine a repeat marble run until the concept is clear.
Imagine that after that marble exits, instead of landing in the litter box it rolls back up along the cat's belly to the mouth. If that image is uncomfortable for you, feel free to imagine washing the marble first. When the marble reaches the mouth, it is back where it started. Imagine it being swallowed and traveling through the digestive tract again. Never once does it enter the inside of the body, never could it contact the internal organs, no matter how many times this exercise is repeated.
The lining of the digestive tract is an extension of the skin and the skin is an extension of the lining. Skin seamlessly shifts to lining right at the inner lipline, check in a mirror to remind yourself. Checking your own lips may be easier than checking those of your cat, cats being cats.
We tend to think of skin as a sort of wallpaper but the skin, including its gut wall extension, is the largest organ of the body. Skin is not paper thin, it is composed of various complex layers and performs active functions.
For the eater, the gut wall is the first line of defense between the outside world and the inside of the body.
Understanding that the inside of the gut is not inside the body is fundamental to understanding what follows, which is why it is the first lesson.
Swallowing food gets food into the digestive tract, into the gut, not into the body. Before food can be put to use in the body, it needs to be digested and then absorbed into the body.
The same is true for drinking water, swallowing puts water into the digestive tract, not into the body. Water does not require digestion but it does need to be absorbed before it can be put to use for its various purposes in the body.
On to Gut 101 – Full Version . . . . . .
“Cats require purity and simplicity.” – SEM