Respiratory System

• Respiration


  The process of gas exchange between the air and an organism's cell
• Types of respiration


  • External respiration
  • Internal respiration
  • Cellular respiration
• External respiration


  Involves inhalation and exhalation of gases
• Internal respiration


  Involves gas exchange between the blood and body cells
• Cellular respiration: Involves the conversion of food to energy
• Respiratory system


  Set of organs that allows a person to breathe and exchange oxygen and carbon dioxide throughout the body
• Respiratory surfaces


  • Structures that different animals use for gas exchange while taking into consideration their environment
  • Area where gas exchange takes place
  • Made up of cells and needs a moist environment
  • Must have large and thin surface area to facilitate easier and faster diffusion of gases
• Types of gas exchange

  • Diffusion
  • Cutaneous respiration
  • Tracheal system
  • Gills
• Diffusion


  • Molecule movement from high concentration to low
  • Present in unicellular organisms such as amoeba and paramecium
  • Allows lower concentration to pass in and out of the unicellular organism
  • Exchange of gases takes place through plasma membrane by simple diffusion
• Cutaneous respiration


  • Gaseous exchange through the skin
  • Breathing through the skin of the organism
  • Animals with this feature has moist and slimy skin which allows gases to easily pass through by diffusion
  • Osmosis = a type of diffusion in which salt forces the water out of an object or organism
• Tracheal system


  • Oxygen and carbon dioxide are exchanged through a network of tubes called tracheae
  • Present in insects as their respiration is separate from the circulatory system
  • Spiracles = used by insects to breathe through openings in the thorax and abdomen, instead of nostrils
• Gills


  • Fishes exchange gases by pulling oxygen-rich water through their mouths and pumping it through their gills
  • Present in aquatic animals
  • Gill filaments = where capillary blood flows in the opposite direction to the water which causes counter current exchange
  • Operculum = protects the gills from harm
• Parts of the human respiratory system

  • Upper respiratory tract
  • Lower respiratory tract
• Nose (external nares)


  • Detects odors in the air and is a resonating chamber for speech
  • Nasal septum = divides the nose into two halves
  • Paranasal sinuses = where air is warmed
  • Cilia = responsible for filtering out foreign bodies
  • Vestibule = Defends from bacteria or other harmful particles
  • Olfactory region = contains highly sensitive cells responsible for the sense of smell
• Pharynx (throat)


  • Common space used by both digestive and respiratory system
  • Acts as a passageway for air to enter the larynx and lungs, and for food and liquid to enter the esophagus
  • Plays a role in speech
  • About 5 inches long
  • Mucosa = lines the inside of the pharynx
  • Skeletal muscle = primarily used for swallowing
• Sections of the pharynx

  • Nasopharynx
  • Oropharynx
  • Hypopharynx
• Nasopharynx


  Contains pharyngeal tonsils (adenoids) = aids in the body's immune defense
• Oropharynx


  Back portion of the mouth that contains palatine tonsils
• Hypopharynx


  Bottom section of the pharynx where the respiratory tract divides into the esophagus and the larynx
• Epiglottis


  • Flap of cartilage located in the throat behind the tongue and in front of the larynx
  • Responsible for sending air, foods, and liquids in their proper system
• Trachea (windpipe)


  • Extends through the mediastinum and lies anterior to the esophagus and inferior to the larynx
  • Contains cartilage rings = reinforces and provide rigidity to the tracheal wall to ensure that the trachea remains open at all times
  • Hyaline cartilage = "C" shaped cartilage which is strong and rigid
• Bronchus


  • Entry point of the lungs
  • Bronchi = two branches of the trachea when it divides
  • Each bronchus branches to a separate lung and subdivides into increasingly smaller branches called bronchioles
  • Bronchospasms = type of spasm of the bronchi, experienced by people with asthma which causes wheezing
  • Bronchioles = smallest branches
• Alveoli


  • Cluster of very small grape-like sacs at the end of the bronchial tree
  • Where oxygen is exchanged with carbon dioxide
  • Intimately associated with capillaries that allow blood cells to filter through one at a time
• Larynx (voice box)


  • Produces sounds
  • Conducts air into the lower respiratory tract
  • Contains vocal cords = vibrates and make sound when air moves against them
  • Adam's apple (laryngeal prominence) = helps protect the walls and the frontal part of the larynx, including the vocal cord, more prominent in males due to testosterone which also causes them to have a deeper voice
• Lungs


  • Core of the respiratory system
  • Two elastic spongy material that expands when filled with air
  • Cone shaped and is divided into lobes
  • Can float in water
  • Primary purpose is gas exchange
• Lobes of the lungs

  • Left lung (superior and inferior lobes)
  • Right lung (superior, middle, and inferior lobes)
• Pleura


  • Serous membrane that folds back on itself to form a two-layered membranous pleural sac and lines the outer surface of each lung and the adjacent internal thoracic wall
  • Visceral pleura = tightly covers the outer surface of each lung
  • Parietal pleura = lines the internal thoracic walls, the lateral surfaces of the mediastinum, and the superior surface of the diaphragm
• Pleural cavities


  • Potential space between the serous membrane layers
  • Pleural fluid = a thin serous fluid that circulates the pleural cavities and acts a lubricant ensuring minimal friction during breathing
  • Pleural effusion = pleuritis with too much fluid
• Aerobic respiration: is a cellular respiration that requires oxygen
• Anaerobic respiration: is a cellular respiration that does not require oxygen