When you finished running the bases, you are sweating and you feel thirsty. what body systems are interacting in this case?

The nervous system makes you thirsty. The integumentary system makes you sweat.

Explanation:

The hypothalamus is part of the nervous system and controls vegetative functions, such as hunger, thirst and body temperature. When you run a race, your body starts to lose fluids due to sweat. At that moment the nervous system (through the hypothalamus) trying to maintain homeostasis in your body signals that you are thirsty.

As already mentioned above, when you participate in a race you start to sweat. This is a reaction of the integumentary system, through the skin, releasing fluids to regulate your body temperature.