Lecture Notes: Nervous System vs. Endocrine System

Key Concepts

• Homeostasis:
  • Also known as regulation.
  • Involves maintaining stable conditions in the body.
  • Examples include maintaining heartbeat, breathing, and digestion.

Nervous System

• Structure:
  • Composed of nerves or neurons.
  • Sends electrochemical messages quickly throughout the body.
• Function:
  • Responds to stimuli (changes in the external or internal environment).
  • Example Responses:
    • Hearing a phone ring and turning head.
    • Seeing a giant bug and moving back.
    • Stubbing a toe and crying out in pain.
    • Touching a hot handle and pulling hand away.

Endocrine System

• Structure:
  • Consists of glands that secrete hormones.
• Function:
  • Sends chemical messages (hormones) through the bloodstream slowly.
  • Hormone messages last longer compared to nervous system messages.
• Examples of Stimulus and Response:
  • Insulin Release:
    • Stimulus: Glucose enters bloodstream.
    • Response: Pancreas releases insulin, which tells liver to store glucose.
  • Growth Hormones:
    • Stimulus: Pituitary gland releases growth hormones.
    • Response: Gradual body growth over time.

Comparison of Systems

• Similarities:
  • Both systems are involved in homeostasis or regulation.
  • Both send messages around the body to initiate responses.
• Differences:
  • Nervous system sends fast electrochemical signals via neurons.
  • Endocrine system sends slow, long-lasting hormonal messages via the bloodstream.