reperatory

• Respiratory system

  The system responsible for breathing and gas exchange
• Where do the products of respiration end up?

  • Carbon dioxide enters the blood and is transported to the lungs where it is released into the air
  • Water is either used in the body or is excreted through the kidneys. The kidney's filter the blood that contains the water molecules.
• Parts of the respiratory or gas exchange system

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


  • Air goes through
  • Nose makes air moist and warm, gas exchange easier
  • 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 cilliated cells that trap microorganisms that might infect lungs, moves them out
• Alveolus

  • Spongy air sacs
  • Site of gas exchange
• Pleura

  • Tough slippery layer surrounding lungs
  • Produce liquid, and slide, allowing lungs to get bigger and smaller
• Diaphragm


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


  • Curved, flat bones, form the thoracic cage
  • Protect lungs and heart
• Gas exchange

  Process where body exchanges oxygen in the air for waste carbon dioxide from your blood
• Why do we breathe?
• Inhaled air

  Relatively high in O2, low in CO2
• Exhaled air

  Relatively low in O2, high in CO2
• Changing air in lungs– keeps gradient steep – fast/efficient gas exchange
• Pressure


  Air will move from an area of high pressure to an area of low pressure
• The thorax


  • The chest
  • Intercostal muscles and diaphragm change shape of the thorax
• Breathing mechanics - Inhalation

  When the diaphragm/intercostal muscles contract, the volume of the thorax increases, this causes the pressure in the thorax to decrease. Air moves into the lungs.
• Breathing mechanics - Exhalation

  When the diaphragm/intercostal muscles relax, the volume of the thorax decreases, this causes the pressure in the thorax to increase. Air moves out of the lungs.
• Inhalation and exhalation


  • Inhalation-Diaphragm flat
  • Exhalation-Diaphragm curved
• Breathing


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


  The movement of air into and out of the lungs
• Respiration


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

  Diaphragm and intercostal muscles contract, volume of thorax increases, pressure decreases, air moves into lungs
• When you breathe out

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


  Site of gas exchange
• Alveoli - function

  • Ensures that: Oxygen diffuses from the alveolus into the blood (capillary)
  • Carbon dioxide diffuses from the blood (capillary) into the alveolus
• What causes the gases to diffuse in the direction they do?
• Alveoli - Adaptations


  • Large surface area - many alveoli are present in the lungs with a shape that increases surface area
  • Thin walls - alveolar walls are one cell thick providing gases with a short diffusion distance
  • Extensive blood supply - ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs
  • A large diffusion gradient - breathing ensures that the oxygen concentration in the alveoli is higher than in the capillaries so oxygen moves from the alveoli to the blood. Carbon dioxide diffuses in the opposite direction.