Science Test 2024

• Respiratory system


  The system responsible for breathing and gas exchange
• Parts of the respiratory system

  • Mouth/Nose
  • Trachea
  • Bronchi
  • Alveolus
  • Capillaries
• Mouth and Nose

  Air goes through, nose makes air moist and warm to aid gas exchange, hair and mucus trap microorganisms
• Trachea

  Carries air from nose to chest and back, cartilage rings hold it open
• Bronchi


  Tubes carry air from trachea to lungs, branch out, lined with ciliated cells that trap microorganisms and move them out
• Alveolus


  Spongy air sacs, site of gas exchange
• Pleura


  Tough slippery layer surrounding lungs, produces liquid to allow lungs to expand and contract
• Diaphragm


  Sheet of muscle that divides the chest from other organs, helps move air in and out of lungs
• Ribs

  Curved, flat bones that form the thoracic cage to protect lungs and heart
• Gas exchange


  Takes place in the lungs, where the body exchanges oxygen in the air for waste carbon dioxide from the blood
• Steep concentration gradient between the air in alveoli and the blood is required for gas exchange to take place
• Inhaled air

  • Relatively high in O2, relatively low in CO2
• Exhaled air


  • Relatively low in O2, relatively high in CO2
• Thorax


  The chest, where the intercostal muscles and diaphragm change the shape to enable breathing
• Inhalation


  When the diaphragm/intercostal muscles contract, the volume of the thorax increases, causing the pressure in the thorax to decrease, and air moves into the lungs
• Exhalation


  When the diaphragm/intercostal muscles relax, the volume of the thorax decreases, causing the pressure in the thorax to increase, and air moves out of the lungs
• Inhalation - diaphragm flat, exhalation - diaphragm curved
• Breathing


  A physical process using the diaphragm and intercostal muscles to change the size of the lungs
• Circulatory system


  Transports materials around the body, including dissolved food, oxygen, and waste products
• Ventilation


  The movement of air into and out of the lungs
• Function of the circulatory system


  • Transport materials around the body
• Respiration


  The chemical breakdown of glucose in our cells, which releases energy (ATP) from glucose
• Blood


  Pumped around the human body in a closed circuit loop made up of the heart and blood vessels
• When you breathe in

  Diaphragm and intercostal muscles contract, volume of thorax increases, pressure decreases, air moves into lungs
• Components of the circulatory system

  • Heart
  • Blood vessels
• When you breathe out

  Diaphragm and intercostal muscles relax, volume of thorax decreases, pressure increases, air moves out of lungs
• Heart


  • The pump that pumps blood around the body
• Alveoli


  Spongy air sacs in the lungs, site of gas exchange
• Blood vessels


  • Carry blood around the body
• Types of blood vessels

  • Arteries
  • Veins
  • Capillaries
• Alveoli adaptations


  • Large surface area, thin walls (one cell thick), extensive blood supply, large diffusion gradient
• Arteries


  Carry blood AWAY FROM THE HEART towards other organs
• Oxygen diffuses from the alveolus into the blood, and carbon dioxide diffuses from the blood into the alveolus
• Smoking


  Increases risk of lung cancer
• Veins


  Carry blood TOWARDS THE HEART and away from organs
• Breathing rate increases with exercise
• Capillaries


  Carry blood through organs, site of gas exchange
• Breathing rate returns to normal after exercise over time
• Components of blood


  • Red blood cells
  • White blood cells
  • Platelets
  • Plasma
• Red blood cells


  Carry oxygen