Respiratory system

• Nose

  • only external visible part of the respiratory system
• Nasal cavity

  • main route of air entry, divided into two equal passages by a septum
  • lined w/ ciliated columnar epithelium - goblet cells - secretes mucus
  • Very vascular
• Nares

  • openings of the nasal cavity
  • anterior and posterior
• Anterior nares

  • openings from the exterior into the nasal cavity
• Posterior nares

  • openings from the nasal cavity into the pharynx
• Paranasal sinuses

  • cavities in the bones of the face and cranium, containing air
• Nasolacrimal ducts

  • extend from the lateral walls of the nose to the conjunctival sacs of the eye
  • drains tears from the eyes
• functions of the nose:

  • olfaction
  • warming
  • filtering & cleaning
  • humidification
• Pharynx

  • aka throat
  • divided into 3 parts - nasopharynx, oropharynx, laryngopharynx
  • rich in MALT
  • smooth muscle
• Pharyngeal muscles

  • keep the pharynx permanently open so that breathing is not interfered
• Constrictor muscles

  • close the pharynx during swallowing, pushing food and fluid into the esophagus
• functions of the pharynx:

  • passageway for air & food
  • warming & humidifying
  • protection
  • speech
• Larynx

  • aka voicebox
  • grows larger in male
  • links the laryngopharynx and the trachea
  • composed of several irregularly shaped cartilages attached to each other by ligaments and membranes
  • 1 thyroid cartilage, 1 cricoid cartilage, 2 arytenoid cartilage, 1 epiglottis
• functions of the larynx:

  • production of sound
  • speech
  • protection of the lower respiratory tract
  • passageway for air
  • humidifying, filtering, & warming
• Trachea

  • aka windpipe
  • continuation of the larynx
  • composed of three layers of tissue, held open by between 16 and 20 incomplete (C-shaped) rings of hyaline cartilage
  • ciliated columnar epithelium - goblet cells - secretes mucus
• functions of the trachea:

  • patency
  • cough reflex
  • warming, humidifying, & filtering
• Sinus

  • lightens the skull
• Mucus

  • sticky fluid
  • traps subtances
• Paranasal sinuses:

  • Maxillary - lateral
  • Frontal - roof
  • Sphenoidal - roof
  • Ethmoidal - upper lateral part
• Pitch

  • depends on the length and tightness of chords
• Volume

  • depends on the force of expired air
• Resonance/tone

  • depends on the shape of the mouth, position of tongue and lips, the facial muscles, and the air in paranasal sinuses
• Carina

  • landmark for separation of 2 bronchi
  • ciliated columnar epithelium
• Right bronchus

  • bronchi that is wider, shorter, more vertical
  • 2.5cm
• Left bronchus

  • bronchi that is narrower
  • 5cm
• function of the bronchi:

  control of air entry
• Lobule

  • small subdivision within an organ
• functions of respiratory bronchioles & alveoli:

  • external respiration
  • defense against infection
  • warming & humidifying
• Lungs

  • right & left
  • cone shaped
  • has apex & base
• Apex

  • narrow superior portion of each lung
• Base

  • broad lung area resting on diaphragm
• Right Lung

  • has 3 lobes - superior, middle, inferior
• Left lung

  • has 2 lobes - superior & inferior
• Pleura

  • a double-layered membrane that surrounds each lung and lines the inner surface of the thoracic cavity
  • visceral & parietal
• Visceral pleura

  • adherent to the lungs, covering each lobe
• Parietal pleura

  • adherent to the inside of the chest wall and the thoracic surface of the diaphragm
• Pleural fluid

  • slippery serous fluid
  • it allows the pleura to glide easily over the thorax wall during breathing
• Intercostal muscles

  • 11 pair of muscles occupying the spaces between the 12 pairs of ribs
  • external & internal
• Diaphragm

  • dome-shaped muscular structure separating the thoracic cavity and the abdominal cavities
• Breathing

  • aka pulmonary ventilation
  • movement of air into and out of the lungs
  • supplies oxygen to the alveoli, and eliminates carbon dioxide