homeostasis and response

• What is homeostasis?

  Maintaining a stable internal environment
• Why is homeostasis important for cells?

  Cells need stable conditions to function properly
• What do automatic control systems regulate?

  Internal environment conditions
• What are the three components of automatic control systems?

  Receptors, coordination centres, and effectors
• How does negative feedback work?

  It counteracts changes to restore normal levels
• What is the first step in negative feedback?

  Receptor detects a stimulus
• What happens when the level is too high?

  Effector produces a response to decrease it
• What happens when the level is too low?

  Effector produces a response to increase it
• How do effectors respond to coordination centre stimulation?

  They continue until the stimulus stops
• What is the role of the nervous system?

  To respond to stimuli and coordinate behavior
• What does the Central Nervous System (CNS) consist of?

  Brain and spinal cord
• What do sensory neurons do?

  Carry information to the CNS
• What do motor neurons do?

  Carry impulses from the CNS to effectors
• What are effectors?

  Muscles and glands responding to impulses
• How do receptors function?

  They detect stimuli
• What happens when light receptors detect bright light?

  Pupil becomes smaller to protect the retina
• What is accommodation in the eye?

  Changing lens shape to focus light
• What occurs when focusing on near objects?

  Ciliary muscles contract, lens becomes fat
• What occurs when focusing on distant objects?

  Ciliary muscles relax, lens becomes thin
• What is hyperopia?

  Long-sightedness due to lens shape
• How can hyperopia be corrected?

  Using glasses with a convex lens
• What is myopia?

  Short-sightedness due to lens shape
• How can myopia be corrected?

  Using glasses with a concave lens
• What are the components of the reflex arc?

  1. Sensory neurone detects stimulus
  2. Impulses travel to the CNS
  3. Relay neurone processes information
  4. Motor neurone sends impulses to effector
  5. Effector produces a response
• What are the methods used to study the brain?

  1. Studying brain damage
  2. Electrically stimulating the brain
  3. MRI scans
• What are the functions of different brain regions?

  • Cerebral cortex: consciousness, intelligence, memory, language
  • Medulla: controls unconscious activities like breathing and heartbeat
• What are the risks of brain investigation and treatment?

  • Physical damage to the brain
  • Increased problems with brain function
• What is the role of the iris in the eye?

  • Controls the diameter of the pupil
  • Regulates light entering the eye
• What is the function of the optic nerve?

  • Carries impulses from the retina to the brain
• What is the role of the ciliary muscles and suspensory ligaments?

  • Control the shape of the lens for focusing
• What happens to the pupil in dim light?

  • Radial muscles contract, circular muscles relax
  • Pupil widens to allow more light
• What happens to the pupil in bright light?

  • Circular muscles contract, radial muscles relax
  • Pupil narrows to protect the retina
• What is the function of the retina?

  • Contains receptor cells sensitive to light intensity and color
• What are the consequences of too much caffeine?

  • Can cause unpleasant side effects
  • Should be avoided after testing
• What is the purpose of measuring reaction time?

  • To assess how quickly a person responds to stimuli
• What factors can affect reaction time?

  • Age
  • Gender
  • Drugs
• How can reaction time be measured using a ruler?

  • Drop a ruler and catch it
  • Measure the distance it fell
• How can reaction time be measured using a computer?

  • Click mouse or press key upon seeing a stimulus
  • Provides precise measurements in milliseconds
• What is the role of the brain in behavior?

  • Controls and coordinates all actions and responses
• What is the significance of studying brain damage?

  • Helps identify functions of damaged brain areas