Respiratory System

• Types of gas exchange

  • Skin system (integumentary system)
  • Gills system
  • Tracheal system (spiracles)
  • Lungs system
• Skin system (integumentary system)

  Breath in oxygen through their moist body surface. Example: frog, worm
• Gills system

  The membrane in most aquatic animals, these are able to get oxygen that has been dissolved in water into their blood stream. Example: fish
• Tracheal system (spiracles)

  Gas exchange in some animals like insects takes place in their trachea, which are several air tubes that form a network in their bodies. Example: insects
• Lungs system


  A pair of organs divided into small chambers filled with capillaries and air sacs. Example: land animals, human
• Respiratory system


  The set of organs that allows a person to breathe and exchange oxygen and carbon dioxide throughout the body
• Major tasks of the respiratory system

  • Exchanging air between the body and the outside environment (external respiration)
  • Bringing oxygen to the cells and removing carbon dioxide from them (internal respiration)
  • Biochemical oxidation of glucose and consequent synthesis of ATP in the cell (cellular respiration)
• Parts of the respiratory system

  • Lung
  • Bronchial tubes
  • Nose
  • Mouth
  • Trachea
  • Diaphragm
• Functions of the respiratory system

  • Supplies the body with oxygen and disposes of carbon dioxide
  • Filters inspired air
  • Produces sound
  • Contains receptors for smell
  • Rids the body of some excess water and heat
  • Helps regulate blood pH
• Breathing (pulmonary ventilation)


  1. Inhalation (inspiration) - draws gases into the lungs

  2. Exhalation (expiration) - forces gases out of the lungs
• External respiration


  Air from the outside environment enters the nose or mouth during inspiration (inhalation)
• Parts of external respiration

  • Nose and nasal cavity
  • Paranasal sinuses
  • Pharynx (throat)
  • Larynx
• Parts of the nose

  • Nostril
  • Nasal septum
  • Nasal cavity
  • Oral cavity
  • Mucous membrane
• Pharynx


  Common space used by both the respiratory and digestive systems, commonly called the throat
• Sections of the pharynx

  • Nasopharynx
  • Oropharynx
  • Laryngopharynx
• Larynx


  Voice box, a short, somewhat cylindrical airway that ends in the trachea
• Trachea


  A flexible tube also called the windpipe, extends through the mediastinum and lies anterior to the esophagus and inferior to the larynx
• Lungs


  • Left lung - divided into 2 lobes, smaller than right lung
  • Right lung - divided into 3 lobes, located more superiorly in the body
• Pleura


  The outer surface of each lung and the adjacent internal thoracic wall are lined by a serous membrane
• Pleural cavity


  The potential space between the serous membrane layers
• How lungs work


  1. Air enters lungs through bronchi

  2. Alveoli are where gas exchange takes place between air and blood

  3. Oxygen travels from alveoli into bloodstream

  4. Carbon dioxide travels from bloodstream into alveoli and is exhaled
• Parts involved in how lungs work

  • Branch of pulmonary vein
  • Branch of pulmonary artery
  • Bronchiole
  • Terminal bronchiole
  • Respiratory bronchiole
  • Capillary beds
  • Alveoli
• Breathing


  1. Lungs are sealed in pleural membranes inside chest cavity

  2. Diaphragm contracts and rib cage rises up during inhalation, expanding chest cavity volume and creating partial vacuum to draw in air

  3. Exhalation is often passive, as rib cage lowers and diaphragm relaxes, increasing pressure in chest cavity to push air out
• Proper care of the respiratory system

  • Stop smoking and stay away from secondhand smoke
  • Avoid indoor and outdoor air pollution
  • Avoid exposure to people with flu or other viral infections
  • Exercise regularly
  • Eat a healthy, balanced diet
  • Maintain a healthy weight
  • See your doctor for an annual physical