Nervous System and Homeostasis

• What is the function of the nervous system?

  It enables organisms to react to surroundings and coordinates behaviour
• What are the two parts of the central nervous system?

  Brain and spinal cord
• Why are reflex actions described as rapid and automatic?

  They do not involve the conscious part of the brain
• Why are reflex actions important?

  For survival and to prevent damage to the body
• Give the pathway of a nervous response.

  Stimulus → receptor → coordinator → effector → response
• Give the function of the cerebral cortex.

  Outer layer of the brain playing an important role in consciousness
• Give the function of the medulla oblongata.

  Part of the brain above the spinal cord that controls breathing and heart rate
• Give the function of the cerebellum.

  Part at the back of the brain involved in coordinating muscle activity
• Why is it difficult to treat brain disorders?

  The brain is very complex and delicate
• What is a synapse?

  Gap between two neurones allowing impulses to cross
• What is the function of neurones?

  Carry electrical impulses around the body
• What is homeostasis?

  Maintenance of a constant internal environment
• Give three internal conditions controlled in homeostasis.

  Body temperature, blood glucose, water levels
• Give three things all control systems include.

  Receptors, coordination centres, and effectors
• What is accommodation?

  Process of changing the shape of the lens to focus on near/distant objects
• Give two common defects of the eyes.

  Myopia and hyperopia
• How can eye defects be treated?

  Spectacle lenses, contact lenses, laser surgery
• Where is body temperature monitored and controlled?

  Thermoregulatory centre in the brain
• What happens if body temperature is too high?

  Blood vessels dilate (vasodilation) and sweat is produced
• What happens if body temperature is too low?

  Blood vessels constrict (vasocontriction) and shivering occurs