Physiologic Reactions

Physiologic Reactions

• Definition: Physiologic reactions are the body's responses to internal or external stimuli, involving various systems and processes.

• Types of Physiologic Reactions:

  • Homeostasis: The body's ability to maintain stable internal conditions despite changes in external environments.

    • Example: Regulation of body temperature through sweating or shivering.

  • Fight or Flight Response: A critical reaction first described by Walter Cannon, preparing the body to either fight a threat or flee from danger.

    • Involves the release of hormones like adrenaline which increase heart rate and energy supply.
    • Example: Elevated heart rate and blood flow to muscles during a stressful event.

• Involvement of Systems:

  • Nervous System: Immediate reactions through electrical signals in response to stimuli.

    • Central nervous system processes information and triggers responses.

  • Endocrine System: Slower, hormonal responses that affect longer-term body functions.

    • Hormones like cortisol regulate energy and stress responses over longer periods.

• Examples of Reactions:

  • Increased Heart Rate: A physiological reaction when experiencing fear, excitement, or exercise.

    • Mechanism: Sympathetic nervous system activation increases pacing of the heart.

  • Dilated Pupils: Reactions to low light or heightened arousal, improving vision.

    • Controlled by the autonomic nervous system, adjusting focus based on environmental needs.

• Importance: Understanding physiologic reactions helps in fields like medicine, psychology, and sports to devise better health strategies and enhance human performance.