Homeostasis Overview Quiz

Homeostasis Overview

• Homeostasis is the body's ability to maintain a relatively stable internal environment despite external changes.
• Homeostasis is crucial for normal bodily function.
• Internal and external changes are part of normal metabolism.
• The body must respond appropriately to these changes.

Homeostasis Example: Eating Breakfast

• Eating breakfast causes an internal change (food in the stomach).
• Specialized proteins are involved in processing the food.

Homeostasis Example: Temperature Regulation

• Body temperature needs to remain within a normal range (97-99°F or 36-38°C).
• A rise in environmental temperature can cause a rise in body temperature.
• The body responds to maintain its normal temperature range (e.g., sweating).

Homeostatic System Components

• Receptor: Monitors changes in the internal or external environment.
• Control center: Processes information from the receptor and sends signals to the effector.
• Effector: Causes a response that opposes or enhances the stimulus.

Homeostatic Regulation Mechanism

• Homeostatic regulation involves three components: receptor, control center, and effector.
• Receptor detects change.
• Control center processes information.
• Effector responds to maintain homeostasis.
• This process is continual.

Homeostatic Regulation Example: Body Temperature When Too Warm

• Receptors in the skin detect changes in body temperature.
• The control center is the brain.
• Effectors are blood vessels and sweat glands to regulate temperature.

Negative Feedback Mechanism

• Responses reverse the initial stimulus.

• Keeps the body within normal limits.

• Example: sweating to cool the body when it's too warm.

• Example: controlling body temperature.

• When the temperature rises above a set point, responses (like sweating) are activated to lower the temperature.

• The opposite happens when temperature drops below the set point.

Negative Feedback Example: Metabolic Rate

• Hypothalamus and pituitary gland detect changes in metabolic rate.
• When metabolic rate decreases, they signal the thyroid gland to produce thyroxine, increasing the metabolic rate.
• When metabolic rate increases, they reduce the signal to the thyroid gland to reduce thyroxine.

Positive Feedback Mechanism

• Responses enhance the initial stimulus.
• Less common in the body than negative feedback.
• Can lead to runaway reactions.
• Example: child birth or some instances of fever—triggers are reinforced until an appropriate termination event.

Positive Feedback Example: Fever

• Bacteria disrupt the body's thermostat in the hypothalamus.
• Body temperature rises; metabolic rate increases and further increases temperature.
• This continues until white blood cells destroy the bacteria, interrupting the cycle.

Positive Feedback Example: Nerve Impulses

• Threshold electrical potential triggers a much larger action potential.
• Blood clotting is another example of positive feedback.

Homeostasis in the Body

• Several organ systems work together to maintain homeostasis. (examples included in the provided image)

Home Heating System vs. Negative Feedback

• A thermostat, sensors, and the furnace are part of a non-biological homeostatic system
• If the temperature increases or decreases, the system reacts to maintain the setpoint.