I have read that if I were to inject animal blood into myself my body would reject it and the results could be disastrous. 

Why is it that I can eat animal meat without causing an immune reaction yet I can’t introduce animal cells into my blood stream?

 

thanks for reading!

33 minutes ago, Tryingtounderstand said:

I have read that if I were to inject animal blood into myself my body would reject it and the results could be disastrous. 

Why is it that I can eat animal meat without causing an immune reaction yet I can’t introduce animal cells into my blood stream?

 

thanks for reading!

From the point of view of the body, the contents of the digestive system are alien, and their processing and absorption into the blood stream is tightly controlled by first denaturing the contents and sterilising the bugs. By injecting anything directly into your bloodstream, you are bypassing those controls. In terms of functioning, the contents of the digestive system are actually outside the body... if that makes sense.... the digestive system tube is surrounded by protective mechanisms acting as gatekeepers.

Edited July 21, 20187 yr by StringJunky

Yes, it's similar to the situation where animals kill and eat venomous snakes. 

They can eat the venom without any harmful effects, but if they got bitten by the snake, the venom would kill them. I remember that there is a trick question, how many poisonous snakes are there in the world? The answer is two (I think). One is a japanese grass snake. Can't remember the other. They will both kill you or make you very ill if you eat them. All of the other dangerous snakes, the ones that can kill you with a bite are VENOMOUS snakes. They aren't poisonous to eat.

The digestive system has evolved to extract the good stuff, and defend you from the bad. Although of course, there are plenty of natural poisons that CAN kill human when eaten.

On 21/07/2018 at 3:53 PM, mistermack said:

Yes, it's similar to the situation where animals kill and eat venomous snakes. 

They can eat the venom without any harmful effects, but if they got bitten by the snake, the venom would kill them. I remember that there is a trick question, how many poisonous snakes are there in the world? The answer is two (I think). One is a japanese grass snake. Can't remember the other. They will both kill you or make you very ill if you eat them. All of the other dangerous snakes, the ones that can kill you with a bite are VENOMOUS snakes. They aren't poisonous to eat.

The digestive system has evolved to extract the good stuff, and defend you from the bad. Although of course, there are plenty of natural poisons that CAN kill human when eaten.

This is because the venom penetrates the stomach lining with acidity, and, gets into your blood stream undigested, yes?

On 8/3/2018 at 4:34 PM, Brett Nortj said:

This is because the venom penetrates the stomach lining with acidity, and, gets into your blood stream undigested, yes?

I'm not aware of snake venoms that can do that. I was talking about the abundant plant and animal poisons that have evolved to protect the owner from being eaten, like frog and toad poison, or the long list of plant poisons.

Snake venom didn't evolve to do that. It's actually modified saliva, I believe, and can't really be too harmful to the digestive system, or it would kill the snakes that produce it. 

If the predator who ate the snake had ulcerated guts, it might get into the blood and kill that way I guess.

On 8/3/2018 at 4:34 PM, Brett Nortj said:

This is because the venom penetrates the stomach lining with acidity, and, gets into your blood stream undigested, yes?

No.
You have entirely missed the point.