the nervous system and the eye

• What is the role of the nervous system in humans?

  It enables humans to react to their environment and coordinate their behavior.
• What are the components of the central nervous system (CNS)?

  The CNS consists of the brain and spinal cord.
• How does the CNS coordinate the response of effectors?


  It coordinates the response by sending signals to muscles or glands.
• What type of responses are reflex actions?

  Reflex actions are automatic and rapid responses that do not involve conscious thought.
• What detects a pain stimulus?

  Receptors detect a pain stimulus.
• How do impulses travel from receptors to the CNS?

  Impulses travel along a sensory neurone to the CNS.
• What happens to an impulse after it reaches the CNS?

  An impulse passes through a relay neurone before reaching the motor neurone.
• What is the role of the effector in a reflex action?

  The effector, usually a muscle, responds to the impulse, such as withdrawing a limb from pain.
• How do neurones communicate with each other?

  Neurones communicate via synapses, which are gaps between neurones.
• What are the main areas of the brain and their functions?

  • Cerebral cortex: responsible for memory and language
  • Cerebellum: coordinates movement
  • Medulla: controls automatic actions such as heartbeat and breathing
• How do neuroscientists study the brain?

  They study patients with brain damage and electrically stimulate different parts of the brain.
• What makes investigating brain disorders difficult?

  The complexity and delicacy of the brain make it challenging to investigate and treat brain disorders.
• What is the function of the retina in the eye?

  The retina contains receptor cells that are sensitive to brightness and color of light.
• What does the optic nerve do?


  The optic nerve carries impulses from the retina to the brain.
• What is the sclera's role in the eye?

  The sclera forms a tough outer layer of the eye.
• What is the function of the iris?

  The iris controls the size of the pupil and the amount of light reaching the retina.
• How do ciliary muscles and suspensory ligaments work together?

  They change the shape of the lens to focus light onto the retina.
• What is accommodation in the eye?

  Accommodation is the process of changing the shape of the lens to focus on near or distant objects.
• What happens to the ciliary muscles and suspensory ligaments when focusing on a near object?

  • Ciliary muscles contract
  • Suspensory ligaments loosen
  • Lens becomes thicker and refracts light more strongly
• What happens to the ciliary muscles and suspensory ligaments when focusing on a distant object?

  • Ciliary muscles relax
  • Suspensory ligaments are pulled tight
  • Lens becomes thinner and refracts light less strongly
• What are the two common defects of the eyes related to light focusing?

  Myopia (short sightedness) and hyperopia (long sightedness).
• How are eye defects generally treated?

  They are treated with spectacle lenses that refract light rays to focus on the retina.
• What are some new technologies for treating eye defects?

  New technologies include contact lenses, laser surgery to change the shape of the cornea, and replacement eye lenses.
• What is the gap between two neurones called?

  The gap is called a synapse.
• Why do pupils become smaller in bright light?

  Pupils become smaller to reduce the amount of light entering the eye and protect the retina.
• What is the role of the ciliary muscles in focusing on objects?

  Ciliary muscles adjust the shape of the lens to focus on near or distant objects.
• How do myopia and hyperopia affect vision?

  Myopia causes difficulty seeing distant objects, while hyperopia causes difficulty seeing near objects.
• What is the purpose of corrective lenses for eye defects?

  Corrective lenses refract light rays so that they focus on the retina.
• What is the significance of new technologies in eye treatment?

  New technologies improve the effectiveness of treatments for eye defects.