37.3 The Respiratory System by vbf10787


									    37.3 The Respiratory System
• Respiration….2 meanings we learn
  – Cellular Respiration: release of energy from food
    in presence of oxygen
  – Organism Respiration: process of gas exchange
    between organism and the environment
     Human Respiratory System
• Basic function is O2 and CO2 exchange
  between blood, air, and tissues
• Pharynx: passageway for air and food
• Larynx: contains vocal cords
• Trachea: wind pipe
  – Epiglottis covers entrance when swallowing
• Bronchi: passageways branching to each lung
• Bronchioles: small passageways in each lung
• Alveoli: air sacs that are site of gas exchange
               Air pathway…
• nose/mouthpharynxlarynxtracheabronchi
  bronchioles alveoli
                 Cilia and Mucus
• Air must be warm, moist, and filtered
• Mucus
   – Moistens air, traps inhaled particles
• Cilia
   – Sweep trapped particles away from lungs, towards
      • Swallowed or spit out
                    Gas Exchange
• 150 million alveoli
  – Lots of surface area…why important?
• Diffusion of O2 and CO2 across capillaries
  – Diffussion….what is it, why does it work here?
• Inhale
  – Diaphram contracts, rib cage moves up
  – Vacuum created, air rushes in to fill it
• Exhale
  – Diaphram relaxes, rib cage lowers
  – Pressure in lungs increases, air rushes out
              Breathing cont…
• Works only because chest is sealed
  – Puncture breaks seal, keeps vacuum from forming
     • “sucking chest wound”
             Breathing controls
• Medulla oblongata regulates
  – Monitors CO2 level
  – As CO2 increases, your urge to breath increases
  – Usually not dependent on O2
• Carbon Monoxide, airplanes, free diving…..
     Tobacco and respiratory sys
• Tobacco contains nicotine, CO, and tar
• Nicotine and CO paralyze cilia
  – Smoker cough
              Smoking Diseases
•   30 % of smokers live to 80
•   55% of nonsmokers live to 80
•   Chronic bronchitis, emphysema, lung cancer
•   Emphysema: loss of elasticity of lung tissue
    – What would this do?
               Diseases cont…
• Lung cancer: 160,000 diagnosed each year
  – Spreads rapidly, few survive 5 years
• Heart disease: smoking doubles risk
  – Smoking causes blood pressure to rise
     • What is high blood
      pressure called???

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