AP Biology Feedback Mechanisms

Which organ systems play a role in homeostasis?

• all of the body systems

• cardiovascular system

• respiratory system

• nervous system

Which two systems work together to maintain homeostasis while transporting oxygen throughout the body and removing carbon dioxide?

• circulatory and respiratory

• respiratory and excretory

• circulatory and digestive

• respiratory and digestive

Identify the initiation event.

Scenario: A person begins to exercise which causes their body temperature to increase. The temperature change is noticed and the person begins to sweat and their body temperature decreases.

• temperature change is noticed

• person begins to sweat

• body temperature decreases

• person begins to exercise

Identify the stimulus event.

• body temperature increases

• person begins to sweat

• temperature change is noticed

• person begins to exercise

Severe blood loss causing an ever-decreasing blood pressure

• positive-feedback mechanism

• negative-feedback mechanism

Tags

NGSS.HS-LS1-3

When you get cut, your skin cells release hormones that signal platelets to come and stop the bleeding. Platelets then release more hormones that signal even more platelets to help stop bleeding. The hormone signals continue until the cut is closed.

• Positive Feedback Response

• Negative Feedback Loop 

Answer explanation

The process described in the question is a Positive Feedback Response. When skin cells release hormones signaling platelets to stop bleeding, and platelets release more hormones to attract even more platelets, it amplifies the response until the cut is closed. This amplification is characteristic of a positive feedback loop, as opposed to a negative feedback loop, which works to maintain stability and balance.

Tags

NGSS.HS-LS1-3

When glucose levels in the blood rise, your brain sends a signal to your pancreas. The pancreas releases insulin, which opens channels in cell membranes to allow glucose to enter the cell, lowering blood sugar levels. 

• Positive Feedback Response

• Negative Feedback Loop 

Answer explanation

The process described in the question is a Negative Feedback Loop. This is because when glucose levels rise, the body responds by releasing insulin to lower these levels. This is a classic example of a negative feedback loop, where the body responds to a change by initiating a response to counteract it and restore balance.

Tags

NGSS.HS-LS1-3

What is the role of a receptor in helping an organism maintain homeostasis? Choose the correct answer

• It receives messages sent by the control center

• It carries out a response to restore internal conditions

• It detects stimuli and sends information to the control center

• It compares current conditions with ideal values for those conditions.

In controlling our body temperature, our body works hard to make corrections to maintain a normal temperature. This is an example of

• negative feedback

• positive feedback

Answer explanation

In controlling our body temperature, our body works to maintain a normal temperature through a process called negative feedback. This mechanism involves the body making corrections to counteract changes in temperature, ensuring a stable internal environment. Positive feedback, on the other hand, amplifies changes rather than counteracting them.

The two types of feedback systems that help organisms maintain homeostasis are:

• positive and negative 

• receptor and effector

• static and dynamic

• minor and major