RESPIRATORY SYSTEM

• Major Tracts of the respiratory system

  • Upper Respiratory Tract
  • Lower Respiratory Tract
• Upper Respiratory Tract


  • Paranasal Sinuses - Frontal and Sphenoid
  • Nose – Nasal Cavity, N. Conchae, N. Vestibule
  • Pharynx
  • Larynx – Epiglottis, Thyroid Cartilage, Cricoid Cartilage
  • Minor parts- Oral cavity, Tongue, Esophagus, vocal cords
• Lower Respiratory Tract


  • Trachea – Carina of Trachea
  • Main Bronchi
  • Lungs – Left and Right
  • Lobar Bronchus – Superior, Inferior, Middle
  • Lingular Division Bronchi
• Bronchi Branching


  Once Bronchi branch into Bronchioles they are identified as distinct structures
• Bronchi Branching Structures


  • Intralobular Bronchiole
  • Terminal Bronchiole
  • Respiratory Bronchiole
• Oxygen Diffusion


  1. Oxygen diffuses alveolus into the capillaries

  2. Capillaries are permeable to oxygen

  3. ~ 5% of the oxygen will be dissolved in the blood plasma

  4. ~ 95% of the oxygen will bind to hemoglobin in red blood cells
• There is a structure Called Pores of Kohn
• Pores of Kohn


  Alveolar pores
• Breathing and Lung Mechanics

  • Ventilation
  • Inspiration
  • Expiration
• Forms of Breathing


  • Quiet Breathing
  • Active or Forceful Breathing
• Inspiration (Inhalation) during normal quiet breathing

  1. Inspiration is initiated by contraction of the diaphragm

  2. Diaphragm moves downward toward the abdomen

  3. Enlarges lung volume

  4. Decreases lung pressure

  5. Air moves from high pressure to low pressure, so air flows INTO the lungs
• Inspiration (Inhalation) during forceful breathing


  1. Inspiration is assisted by the intercostal muscles

  2. Intercostal muscles contract, the rib cage moves upward and outward

  3. Enlarges lung volume

  4. Decreases lung pressure

  5. Air moves from low pressure to high pressure, so air flows INTO the lungs
• Expiration (Exhalation) during normal quiet breathing

  1. Expiration is initiated by RELAXATION of the diaphragm

  2. Diaphragm moves UPWARD toward the thorax (chest)

  3. Decreases lung volume

  4. Increases lung pressure

  5. Air moves from high pressure to low pressure, so air flows OUT OF the lungs

  6. Expiration is normally a passive process and does not require muscles to work
• Expiration (Exhalation) during forceful breathing

  1. Expiration is initiated by the RELAXATION of the intercostal muscles

  2. Intercostal muscles relax, the rib cage moves downward and inward

  3. Decreases lung volume

  4. Increases lung pressure

  5. Air moves from high pressure to low pressure, so air flows OUT OF the lungs
• Secondary processes of respiration

  • Stimulation of Breathing
  • Respiration control centers
  • Chemoreceptors
• Respiration control centers


  The medulla which sends signals to the muscles involved in breathing, and the pons which controls the rate of breathing
• Chemoreceptors


  Receptors in the medulla and in the aortic and carotid bodies of the blood vessels that detect changes in blood pH and signal the medulla to correct those changes
• Air will move in or out of the lungs

  Depending on the pressure in the alveoli
• The body changes the pressure in the alveoli


  By changing the volume of the lungs
• As volume increases


  Pressure decreases
• As volume decreases


  Pressure increases
• Bronchial tree refers to the network of airways within the lungs.
• The bronchi are two tubes that branch off from the trachea into the lungs.
• The trachea is the windpipe, which connects to the larynx.
• Alveolar ducts are small tubes that connect the terminal bronchiole with the alveoli.
• At the end of these small branches are clusters of tiny sacs called alveoli.
• The right lung has three lobes (upper, middle, lower) while the left lung has only two (upper, lower).
• Each lung has its own bronchus, which divides into smaller branches called bronchioles.
• Respiration is the process by which oxygen enters the body through breathing and carbon dioxide leaves the body during exhalation.
• BRONCHIOLES SPLIT TO FORM ALVEOLI, HELPING>


  LARGE SURFACE AREA FOR GAS EXCHANGE
• ALVEOLAR SURFACE IS MOIST SO..

  GAS CAN BE ALLOWED TO DISSOLVE IN WATER FOR DIFFUSION.
• THE WALL OF THE ALVEOLI IS ONE CELL THICK B/C

  EFFICIENT GAS DIFFUSION
• NETWORK OF BLOOD CAPILLARIES ARE SURROUNDED BY ALVEOLI


  TO ALLOW THE CARBON DIOXIDE TO BE BROUGHT TO ALVEOLI

  OYXGEN TO BE TAKEN AWAY
• FOUR RESPIRATION PROCESSES

  • VENTILATION (BREATHING): AIR IN, AIR OUT
  • EXTERNAL RESPIRATION: GAS EXCHANGE BTWN AIR & BLOOD
  • INTERNAL RESPIRATION: GAS EXCHANGE BTWN TISSUES & BLOOD
  • CELLULAR RESPIRATION: OXYGEN USE TO CERATE ATP, CARBON DIOXIDE AS WASTE.
• TWO PHASES OF VENTILATION

  • INSPIRATION
  • EXPIRATION