RESPIRATORY SYSTEM

• • Olfactory receptors are located in the mucosa on the superior surface
• ·Cavities within bones surrounding the nasal cavity

  • Frontal bone
  • Sphenoid bone
  • Ethmoid bone
  • Maxillary bone
• Function of the sinuses

  • Lighten the skull
  • Act as resonance chambers for speech
  • Produce mucus that drains into the nasal cavity
• PHARYNX

  • Muscular passage from nasal cavity to larynx
• Three regions of the pharynx

  Nasopharynx – superior region behind nasal cavity

  Oropharynx – middle region behind mouth

  Laryngopharynx – inferior region attached to larynx
• Tonsils of the pharynx

  • Pharyngeal tonsil (adenoids) in the nasopharynx
  • Palatine tonsils in the oropharynx
  • Lingual tonsils at the base of the tongue
• LARYNX

  • Routes air and food into proper channels
  • Plays a role in speech
  • Made of eight rigid hyaline cartilages and a spoon-shaped flap of elastic cartilage (epiglottis)
• TRACHEA

  • Connects larynx with bronchi
• TRACHEA

  • Walls are reinforced with C-shaped hyaline cartilage
• PRIMARY BRONCHI

  • Formed by division of the trachea
  • Enters the lung at the hilus (medial depression)
  • Right bronchus is wider, shorter, and straighter than left
  • Bronchi subdivide into smaller and smaller branches
• LUNG

  • Occupy most of the thoracic cavity

  -Apex is near the clavicle (superior portion)

  -Base rests on the diaphragm (inferior portion)
• LUNG

  • Each lung is divided into lobes by fissures

  Left lung – two lobes

  Right lung – three lobes
• Pulmonary (visceral) pleura covers the lung surface
• Parietal pleura lines the walls of the thoracic cavity
• TREE DIVISION

  ·Primary bronchi

  ·Secondary bronchi

  ·Tertiary bronchi

  ·Bronchioli

  ·Terminal bronchioli
• BRONCHIOLES

  ·Smallest branches of the bronchi
• Thin squamous epithelial layer lining alveolar walls
• Pulmonary ventilation – moving air in and out of the lungs
• External respiration – gas exchange between pulmonary blood and alveoli
• Respiratory gas transport – transport of oxygen and carbon dioxide via the bloodstream
• Internal respiration – gas exchange between blood and tissue cells in systemic capillaries
• Inspiration – flow of air into lung

  Expiration – air leaving lung
• INSPIRATION

  ·Diaphragm and intercostal muscles contract

  ·The size of the thoracic cavity increases

  ·External air is pulled into the lungs due to an increase in intrapulmonary volume
• EXHALATION

  ·Largely a passive process which depends on natural lung elasticity

  ·As muscles relax, air is pushed out of the lungs

  ·Forced expiration can occur mostly by contracting internal intercostal muscles to depress the rib cage
• ·Residual volume of air – after exhalation, about 1200 ml of air remains in the lungs
• ·Normal breathing moves about 500 ml of air with each breath (tidal volume [TV])
• Factors Influencing Respiratory Rate and Depth

  1. PHYSICAL FACTORS
  2. VOLITION
  3. EMOTIONAL FACTORS
  4. CHEMICAL FACTORS
• AGING EFFECTS

  ·Elasticity of lungs decreases

  ·Vital capacity decreases

  ·Blood oxygen levels decrease

  ·Stimulating effects of carbon dioxide decreases

  ·More risks of respiratory tract infection
• ·Newborns – 40 to 80 respirations per minute
• ·Infants – 30 respirations per minute
• ·Age 5 – 25 respirations per minute
• ·Adults – 12 to 18 respirations per minute