HOMEOSTASIS + RESPONSE

• What is the main focus of homeostasis?

  Regulation of internal conditions
• Why do cells require a constant temperature and pH?

  To maintain optimum conditions for function
• What do control systems in the body monitor?

  Composition of blood and tissues
• What are the components of control systems in the body?

  Receptors, coordination centres, effectors
• What is the role of receptors in control systems?

  Detect stimuli in the environment
• What is the function of coordination centres?

  Receive and process information from receptors
• What do effectors do in control systems?

  Bring about responses to restore levels
• How does the nervous system help humans?

  Enables reaction to surroundings and behavior coordination
• What are neurones responsible for?

  Passing information as electrical impulses
• What does the central nervous system (CNS) consist of?

  Brain and spinal cord
• What is the role of reflex actions?

  Automatic and rapid responses
• What are the components of a reflex arc?

  Sensory neurone, synapse, relay neurone, motor neurone
• Why are reflex actions important?

  They allow quick responses without conscious thought
• What does the brain control?

  Complex behaviour
• What is the structure of the brain made of?

  Billions of interconnected neurones
• What are the main regions of the brain?

  Cerebral cortex, cerebellum, medulla
• How do neuroscientists study brain function?

  By studying patients with brain damage
• What is the challenge in treating brain disorders?

  The complexity and delicacy of the brain
• What is the function of the eye?

  To detect light intensity and colour
• What is accommodation in the eye?

  Changing lens shape to focus
• How do ciliary muscles help in focusing on near objects?

  They contract to thicken the lens
• What happens to the suspensory ligaments when focusing on a distant object?

  They are pulled tight
• What are common defects of the eye?

  Myopia and hyperopia
• How are myopia and hyperopia treated?

  With spectacle lenses
• What is the role of the thermoregulatory centre?

  To monitor and control body temperature
• What happens when body temperature is too high?

  Blood vessels dilate and sweat is produced
• What occurs when body temperature is too low?

  Blood vessels constrict and shivering occurs
• What is the endocrine system composed of?

  Glands that secrete hormones
• How do hormones affect target organs?

  They produce effects after being carried by blood
• What is the role of the pituitary gland?

  Secretes hormones in response to body conditions
• What are some uses of plant hormones?

  Control growth and responses to light
• What is auxin used for in agriculture?

  Weed killers and rooting powders
• How does ethene affect fruits?

  Controls ripening during storage
• What do gibberellins do in plants?

  End seed dormancy and promote flowering
• What are the key components of homeostasis?

  • Regulation of blood glucose concentration
  • Control of body temperature
  • Maintenance of water levels
• What are the functions of the eye's structures?

  • Retina: detects light
  • Optic nerve: transmits visual information
  • Sclera: protects the eye
  • Cornea: refracts light
  • Iris: controls pupil size
  • Ciliary muscles: adjust lens shape
  • Suspensory ligaments: hold lens in place
• What are the mechanisms for temperature regulation in the body?

  • Vasodilation: blood vessels widen to cool down
  • Sweating: evaporative cooling
  • Vasoconstriction: blood vessels narrow to retain heat
  • Shivering: muscle contractions to generate heat
• What are the roles of the human endocrine system?

  • Secretes hormones into the bloodstream
  • Regulates various body functions
  • Coordinates long-term changes in the body
• How do plant hormones affect growth?

  • Auxins: promote growth and control direction
  • Gibberellins: initiate seed germination and flowering
  • Ethene: regulates fruit ripening
• What are the effects of myopia and hyperopia?

  • Myopia: distant objects appear blurry
  • Hyperopia: near objects appear blurry