Critical Thinking #1
Pleurisy affects the membranes that surround the lungs which would be the serous membranes. Their normal role is to create a lubricating fluid that prevents friction. John’s condition is probably so painful because the lubricating fluid is not being secreted and therefore friction is occurring. The pain he is experiencing is probably a result of the friction.
Critical Thinking #4
Dehydration and thirst is the cause of a negative feedback. When the body does not have enough water, a sensor detects the imbalance and sends signals to the brain and through the body telling it to obtain more fluids and once it becomes rehydrated and the body goes back to homeostasis, the thirst goes away.