respiratory system

• Cellular Respiration


  1. Uses O2 to turn glucose into ATP (CO2 is a byproduct)

  2. Occurs in the mitochondria
• Organismal respiration

  Exchange of gases between cells of an organism and the environment
• Main Organs

  • Nasal cavity
  • Pharynx
  • Epiglottis
  • Larynx (voice box)
  • Trachea
  • Bronchi
  • Bronchioles
  • Diaphragm
• Air flow

  1. Air enters through the nose or the mouth, passes through nasal cavity, enters the pharynx

  2. If no food is being ingested, the epiglottis allows air to move into the larynx
• The Larynx

  Air entes the larynx, where the vocal cords are, exhaled air causes them to vibrate, producing sound
• Bronchi and Bronchioles

  1. Air moves into the trachea that divides into two bronchi (singular bronchus)

  2. Each bronchi branches out into many several bronchioles
• The Alveoli

  • Microscopic air sacs where gas exchange occurs by diffusion
  • The thin walls of the alveoli and blood capillaries give a small distance for oxygen and carbon dioxide to diffuse across making gas exchange efficient
• Gas exchange

  1. Diffusion of gases across the alveoli

  2. CO2 gets exchanged with O2, with help of blood flowing through nearby capillaries

  3. Oxygenated blood returns to the heart, which then pumps it to the body
• Breathing


  Air is inhaled actively and exhaled passively
• The Diaphragm


  • Sheet of skeletal muscle located beneath the lungs
  • Air flow is controlled by the diaphragm
  • Air moves in ——> diaphragm contracts downward
  • Air moves out ——> diaphragm relaxes upwards
• Sinusitis


  • Inflammation of the sinuses
  • Causes: infections, allergies, deviated septum
  • Symptoms: facial pain / pressure, congestion
• Laryngitis


  • Inflammation of the larynx
  • Causes: infections, overuse of voice, allergic irritation
  • Symptoms: hoarseness, weak voice, sore throat
• Asthma


  • Narrowing of bronchioles
  • Causes: genetics, allergies, infections, air pollution
  • Symptoms: wheezing, chest pain, breathlessness
• Emphysema


  • Damage to the walls of the alveoli
  • Chronic and incurable
  • Cause: smoking
  • Symptoms: shortness of breath, coughing
• Lung Cancer

  • Uncontrolled growth of abnormal lung cells
  • Causes: smoking, exposure to pollutants
  • Symptoms: difficulty breathing, fatigue, coughing blood
• C6 H12 O6 + 6O2 ——> 6H2O + 6CO2 + 36 ATP