Science

• Nervous system


  Made up of the brain, the spinal cord, and the nerves
• Brain


  A mass of nerve cells located in the head
• Spinal cord


  Extending from the brain
• Nerves


  Extend from the brain and spinal cord to the different parts of the body
• Brain


  • Protected by the skull and layers of tissues called meninges
  • Surrounded by cerebrospinal fluid that cushions the brain and spinal cord against shock
• Major parts of the brain

  • Cerebrum
  • Cerebellum
  • Medulla oblongata or brain stem
• Cerebrum


  Largest structure in the brain, responsible for controlling speech, memory, emotions, intelligence, reasoning, thinking, and sensations
• Right hemisphere


  Controls the left side of the body
• Left hemisphere


  Controls the right side of the body
• Lobes of the cerebrum

  • Frontal lobe - movement and speech
  • Parietal lobe - touch and taste
  • Occipital lobe - sight
  • Temporal lobe - hearing and smell
• Cerebellum


  Second largest part of the brain, specifically responsible for balance, posture, and movement coordination
• Medulla oblongata or brain stem


  Found at the base of the brain, connects the brain to the spinal cord, controls basic life functions such as heartbeat, breathing, and digestion, concerned with reflex actions
• Excretion


  The process by which waste materials are removed from the body
• Waste materials excreted from the body

  • Carbon dioxide (lungs)
  • Undigested food/feces (large intestine and rectum)
  • Excess water and salt (through pores in the skin)
• Urinary system


  The system responsible for excreting most of the liquid wastes from the body
• Main parts of the urinary system

  • Kidneys
  • Ureters
  • Urinary bladder
  • Urethra
• Urine


  The liquid waste of the body filtered through the urinary system
• Kidneys


  • Two bean-shaped organs on each side of the body
  • Main organs of the urinary system
  • Filter and clean the blood to remove waste substances and ensure only useful substances stay in the blood
  • Remove excess water, salts, urea, and other wastes from the blood
  • Each kidney has thousands of filters called nephrons that filter the blood about 300 times a day
• Blood filtration by kidneys

  1. Blood is carried to the kidneys

  2. Kidneys filter excess water and waste from the blood

  3. Blood goes back to the heart

  4. Blood goes to the lungs to receive oxygen

  5. Blood returns to the heart to be pumped and distributed to different parts of the body
• Kidney structure


  • Medulla
  • Cortex