Lesson 2: Homeostasis: Negative & Positive Feedback

Question 1

What is homeostasis?

Answer 1

The ability to maintain a stable internal environment in response to environmental changes.

Homeostasis is crucial for the physiological constancy of the body despite external fluctuations.

Question 2

What are some examples of homeostasis in the human body?

Answer 2

• Blood pH
• Blood pressure
• Body temperature
• Blood glucose levels

Specific ranges include: Blood pH (7.35-7.45), Blood pressure (120/80), Body temperature (36.4-37.6°C), Blood glucose (70-100 mg/dL).

Question 3

What are the three functional components of homeostatic control systems?

Answer 3

• Receptor (detects change)
• Control center (processes information)
• Effector (produces an appropriate response)

The effector typically refers to a muscle or gland that responds to the control center’s command.

Question 4

True or False: Homeostatic control systems involve a feedback system.

Answer 4

True

Feedback systems are essential for maintaining homeostasis by invoking responses that alter original stimuli.

Question 5

Fill in the blank: A feedback system involves a _______ from one part of the body invoking a response from another part.

Answer 5

stimulus

This response acts to alter the original stimulus.

Question 6

What does the control center in a homeostatic system do?

Answer 6

Processes information from the receptor.

The control center is crucial for determining the appropriate response to maintain homeostasis.

Question 7

What type of feedback may body systems be regulated by?

Answer 7

Negative feedback

Negative feedback systems help to counteract changes and maintain stability in the internal environment.

Question 8

What is the primary mechanism that controls homeostasis?

Answer 8

Feedback mechanisms

Feedback mechanisms are essential for maintaining stable internal conditions in an organism.

Question 9

What does negative feedback do?

Answer 9

Diminishes or counteracts the stimulus to re-establish homeostasis

Negative feedback is crucial for returning the body to its normal state.

Question 10

What are control centers in the context of negative feedback?

Answer 10

Areas, such as the hypothalamus in the brain, that monitor and control body conditions

Control centers are vital for regulating various physiological parameters.

Question 11

What is the role of receptors in negative feedback?

Answer 11

Detect unacceptable levels and signal the appropriate control center

Receptors are responsible for sensing changes in the internal environment.

Question 12

What happens when a receptor detects a condition like low temperature?

Answer 12

It stimulates the brain to initiate an adaptive response, such as shivering

This response helps to restore normal body temperature.

Question 13

What is an adaptive response?

Answer 13

A behavior directed by the control center to regain a normal state

Adaptive responses are crucial for survival and maintaining homeostasis.

Question 14

What occurs once a normal state is regained in negative feedback?

Answer 14

The receptor stops signaling the control center

This cessation prevents unnecessary responses and conserves energy.

Question 15

How does negative feedback maintain glucose levels in the blood?

Answer 15

The concentration of glucose averages out to be a stable level over time

This illustrates how the body regulates vital parameters within specific ranges.

Question 16

True or False: Negative feedback only occurs when conditions are exactly at the desired level.

Answer 16

False

Negative feedback operates within a range, rather than at a single fixed point.

Question 17

Fill in the blank: Negative feedback results in a _______ response.

Answer 17

counteractive

This type of response helps to maintain stability in the body’s internal environment.

Question 18

What is a classic example of negative feedback provided in the text?

Answer 18

Temperature control in your house

This analogy helps to illustrate how negative feedback mechanisms function.

Question 19

What is the primary role of a thermostat in homeostasis?

Answer 19

To detect temperature changes and regulate the heating system

The thermostat acts as a receptor that senses when the temperature drops and sends a signal to the furnace.

Question 20

What happens when the house temperature drops?

Answer 20

The thermostat detects low temperature and sends a signal to the furnace

This initiates a negative feedback loop to restore normal temperature.

Question 21

What is negative feedback?

Answer 21

A process that counteracts a change to return to a set point

It helps maintain homeostasis by reducing the effect of the original stimulus.

Question 22

What is a stimulus in the context of homeostasis?

Answer 22

A change in the environment that triggers a response

For example, a drop in temperature is a stimulus that activates the thermostat.

Question 23

Fill in the blank: In negative feedback, the _______ is the component that receives the stimulus.

Answer 23

receptor

Question 24

What is the function of the control center in negative feedback?

Answer 24

To process the information received from the receptor and determine the appropriate response

The control center is often a part of the nervous or endocrine systems.

Question 25

What is an effector in the context of negative feedback?

Answer 25

The component that acts to restore normalcy after a stimulus ## Footnote In the temperature example, the furnace acts as the effector.

Question 26

True or False: Positive feedback amplifies changes in the system.

Answer 26

True

Question 27

List two examples of negative feedback in the human body.

Answer 27

* Regulation of blood glucose levels * Regulation of body temperature

Question 28

What does the term 'normalcy' refer to in homeostasis?

Answer 28

The stable internal conditions the body aims to maintain ## Footnote Normalcy is the state of equilibrium for physiological parameters.