homeostasis and response

• What is the definition of homeostasis?

  Regulation of internal conditions for optimum function
• Why do enzymes require stable conditions?


  They cannot work well if conditions change
• What are the three internal conditions homeostasis regulates in the human body?

  Blood glucose concentration, body temperature, water levels
• What are the key features of automatic control systems in the body?

  • Involves nervous system or hormones
  • Detects changes via receptor cells
  • Processes information in a Coordination Center
  • Sends instructions to effectors (muscles or glands)
  • Carries out responses to maintain homeostasis
• What is a stimulus in the context of homeostasis?

  A change to the environment
• What role do receptor cells play in homeostasis?

  They detect changes in the environment
• What is the function of the Coordination Center?

  Processes information from receptor cells
• What is an effector in the context of homeostasis?

  A muscle or gland that carries out responses
• How does the body respond to a fall in blood glucose concentration during exercise?

  Homeostasis mechanisms restore glucose levels
• What components are involved in the homeostasis process?

  1. Stimulus
  2. Receptor
  3. Coordination Center
  4. Effector
  5. Response
• Where can you find more questions on homeostasis?

  In the vision workbook linked above
• What is homeostasis?

  Keeping internal conditions as constant as possible
• What are the components of an automatic control system?

  Stimulus, receptor, coordination center, effector, response
• What are the two parts of the nervous system?

  Central nervous system and peripheral nerves
• What does the central nervous system consist of?

  Brain and spinal cord
• What is the role of receptors in the nervous system?

  Detect stimuli and send impulses
• What are neurons?

  Nerve cells that transmit electrical impulses
• What is the function of effectors?

  Bring about a response
• What are the two types of effectors mentioned?

  Muscles and glands
• How does the nervous system help humans?

  Enables reaction to surroundings and behavior coordination
• What happens when you touch a hot object?

  The reflex arc is activated
• What is the reflex arc?

  A pathway for reflex actions
• What is the first step in the reflex arc when touching a hot object?

  The stimulus is detected by a receptor
• What type of neuron carries impulses to the central nervous system?

  Sensory neuron
• What is a synapse?

  A junction between neurons
• What happens at the synapse between sensory and relay neurons?

  A chemical is released to trigger an impulse
• What triggers an electrical impulse in the relay neuron?

  A chemical released from the sensory neuron
• What happens after the relay neuron in the reflex arc?

  The impulse triggers a motor neuron
• What is the role of the motor neuron in the reflex arc?

  Transmits impulses to the effector
• What is the effector in the reflex arc when touching a hot object?

  A muscle that contracts
• What is the response when you touch a hot object?

  Pulling the hand away
• How do reflexes differ from other actions in terms of brain involvement?

  Reflexes do not involve conscious brain decisions
• What are the stages of the reflex arc?

  1. Stimulus detected by receptor
  2. Impulse travels along sensory neuron
  3. Chemical released at synapse to relay neuron
  4. Impulse travels along relay neuron
  5. Chemical released at synapse to motor neuron
  6. Impulse travels down motor neuron to effector
  7. Effector (muscle) contracts, pulling away
• Why are reflexes important?

  They help protect us from danger
• What are the roles of the central nervous system in homeostasis?

  • Acts as a coordination center
  • Processes information from receptors
  • Sends impulses to effectors for response
• What is the function of the cornea?

  • Starts the focusing of light rays
  • Transparent front of the eye
• What is the colored part of the eye called?

  The iris
• What is the role of the lens in the eye?

  To focus light rays onto the back of the eye
• What is accommodation in the context of the eye?

  Changing the lens shape to focus
• What is the back of the eye called?

  The retina