Question

The presence of a full bladder triggers the bladder to contract. As a little urine is released, this causes more contractions, which will completely empty the bladder. This is an example of: a. homeostatic regulation d. positive feedback b. uroregulation e. reverse feedback c. negative feedback

Short answer

Positive feedback

Step-by-step solution

- Understand the Scenario

First, understand what is being described: the presence of a full bladder causes it to contract, releasing some urine. The release of some urine causes more contractions until the bladder is completely empty.

- Identify the Feedback Mechanism

Determine the type of feedback mechanism based on the description. A process that amplifies or increases the response is usually called positive feedback, whereas a process that reduces or dampens the response is negative feedback.

- Match with Given Options

Compare the scenario with the given answer choices: homeostatic regulation, positive feedback, uroregulation, reverse feedback, and negative feedback. Identify which description matches the process where the response amplifies the initial stimulus.

- Choose the Correct Answer

Positive feedback is the mechanism where the response to a stimulus increases the change. Here, as urine is released, the contractions increase, fitting the definition of positive feedback.

Key concepts

Feedback Mechanisms

Feedback mechanisms are processes that help the body maintain balance. They regulate functions by either amplifying (positive feedback) or reducing (negative feedback) the initial stimulus. This is key to many bodily functions.

In physiology, positive and negative feedback have distinct roles:

• Positive Feedback: This mechanism increases the effect of the original stimulus. It pushes processes to complete, often in a rapid and self-amplifying cycle. For example, the release of oxytocin during childbirth increases contractions.


• Negative Feedback: This mechanism counteracts changes, bringing them back to a set point to maintain stability. An example is the regulation of blood glucose levels.

The bladder contraction described is a clear example of positive feedback. The initial release of urine triggers more contractions until the bladder is entirely empty.

Bladder Contraction

Bladder contraction is an essential process in the urinary system. When the bladder is full, it triggers a series of contractions to empty itself.

This involuntary process is driven by the nervous system. Here’s how it works:

• The bladder muscles stretch when filled with urine, sending signals to the brain.


• The brain then sends back signals to start muscle contractions.


• As some urine is released, this action triggers further contractions.

Because each small release of urine leads to stronger subsequent contractions, the entire bladder eventually empties. This self-amplifying process is a classic example of positive feedback in action.

Homeostasis

Homeostasis is the body's way of maintaining a stable internal environment. It's crucial for keeping bodily functions in balance, despite changes in external conditions.

This regulation involves:

• Receptors: Detect changes in the environment.


• Control Center: Processes the information and decides the response (often the brain).


• Effectors: Carry out the response to adjust the internal condition.

An important point is that homeostasis often relies on negative feedback mechanisms. However, positive feedback mechanisms, like the bladder contraction, play a specific role in processes that need to be completed once initiated, such as childbirth or blood clotting.

By understanding these concepts, students gain insight into how the body self-regulates, ensuring survival and functionality in different situations.