BIO 131 CH 22 Respiratory System

• Respiratory system


  Organ system that takes in air and expels it from the body
• Respiration


  Ventilation of the lungs (breathing)
• Functions of the respiratory system

  • Gas exchange
  • Communication
  • Olfaction
  • Acid-base balance
  • Blood pressure regulation
  • Blood and lymph flow
  • Platelet production
  • Blood filtration
  • Expulsion of abdominal contents
• Conducting zone


  Passages that serve only for airflow (no gas exchange)
• Respiratory zone


  Regions that participate in gas exchange
• Upper respiratory tract


  Airway from nose through larynx
• Lower respiratory tract


  Regions from trachea through lungs
• Nose


  Warms, cleanses, and humidifies inhaled air; detects odors; and serves as a resonating chamber that amplifies voice
• Nose


  • Extends from nostrils (nares) to posterior nasal apertures (choanae)
  • Facial part is shaped by bone and hyaline cartilage
• Nasal septum


  Divides nasal cavity into right and left nasal fossae
• Vestibule


  Small, dilated chamber just inside nostrils, lined with stratified squamous epithelium
• Vibrissae


  Stiff hairs that block insects and debris from entering nose
• Nasal conchae (turbinates)


  Three folds of tissue that project from lateral walls toward septum
• Meatus


  Narrow air passage beneath each concha
• Respiratory epithelium


  Ciliated pseudostratified columnar epithelium
• Goblet cells


  Produce most of the mucus, supplemented by mucous glands in lamina propria
• Ciliated cells


  Have motile cilia that propel the mucus posteriorly toward pharynx to be swallowed
• Olfactory epithelium


  Involved in the sense of smell, located at roof of each nasal fossa
• Olfactory glands


  Secrete serous fluid to assist diffusion of odor molecules to receptors on the cilia
• Erectile tissue (swell body)

  Extensive venous plexus in epithelium of inferior concha that swells with blood to restrict airflow through that fossa
• Pharynx


  Muscular funnel extending about 13 cm (5 in.) from posterior nasal apertures to larynx, divided into three regions
• Nasopharynx


  Posterior to nasal apertures and above soft palate
• Oropharynx


  Space between soft palate and epiglottis
• Laryngopharynx


  Posterior to larynx, from epiglottis to cricoid cartilage
• Larynx


  Cartilaginous chamber about 4 cm (1.5 in.) long, primary function is to keep food and drink out of airway
• Larynx


  • Epiglottis
  • Vestibular folds
  • Vocal cords (vocal folds)
  • Glottis
• Extrinsic muscles


  Superficial layer of muscles connecting larynx to hyoid bone, elevate larynx during swallowing
• Intrinsic muscles


  Deeper layer of muscles that pull on corniculate and arytenoid cartilages, causing them to pivot
• Trachea


  Tube that connects larynx to bronchi
• Trachea


  • Rigid tube 12 cm (4.5 in.) long and 2.5 cm (1 in.) in diameter
  • Supported by 16 to 20 C-shaped rings of hyaline cartilage
  • Trachealis muscle spans opening in rings
• Mucociliary escalator

  Mechanism for debris removal, mucus traps inhaled particles and upward beating cilia moves mucus to pharynx to be swallowed
• Adventitia


  Outermost layer of trachea, fibrous connective tissue that blends into adventitia of other, nearby organs
• Tracheotomy


  To make a temporary opening in the trachea and insert a tube to allow airflow
• Intubation


  When a patient is on a ventilator, air is introduced directly into trachea
• Lung


  Conical organ with a base, apex, costal surface, mediastinal surface, and hilum
• Lungs


  • Right lung has three lobes, left lung has two lobes
  • Bronchial tree - a branching system of air tubes in each lung
• Main (primary) bronchi


  Arise from fork of trachea
• Lobar (secondary) bronchi


  A lobar bronchus serves each lobe of the each lung
• Segmental (tertiary) bronchi


  10 in right lung, 8 in left lung
• Bronchopulmonary segment


  Functionally independent unit of lung ventilated by segmental bronchus