Ok. Lets pretend you see a habitat in the wood. You see the food chain of all the animals. mouse, fox, bear, human. Lets say a zoo decides to get rid of their foxes and dumps them in this forest. Then, instead of 20, you have 30 foxes. All of the mice are gone in a matter of weeks. So the Foxes start to slowly drop out. Then, theres not much for the bears to eat, so the bears start dying. Then, the humans can't hunt bears. It sets the whole chain of the forest off. Next, the humans will switch to dears, and all the dears will be killed off... etc... etc... Make sense? Got a question? Message me for more details and more questions!
Let's Take for example the activation of renin-angiotensin system, renin is secreted by the kidney, then it will convert the angiotensinogen (previously dry by the liver) into angiotensin I, then it will be converted into angiotensin II by the enzyme conversion at the level of the lungs, and finally angiotensin II will act at the level of the vessels to exert the vasoconstriction.
This example shows the harmony between the different organs (the kidneys, the liver, the lungs and the vascular system) for the functioning of the renin-angiotensin system.
