Human Anatomy (205)

Respiratory System

• Nose, Nasal Cavity [see LMC Lab Model]
• Nostrils (external nares) opening into nasal cavity
• Internal nares opening bewteen nasal cavity and nasopharynx
• Paranasal sinuses communicate with nasal cavity [sphenoid, ethmoid, frontal, maxillary]
• Pharynx [nasopharynx, oropharynx, laryngopharynx]

  Larynx [7] * lab model Supported by wide cartilage rings (Thyroid cartilage [8] & cricoid cartilage [9]) Glottis is opening into larynx Vocal folds border glottis * see video Glottis is shielded by epiglottis during swallowing Trachea [6], located in mediastinum and is beginning of bronchial tree Components of Bronchial Tree See components on Lab Torso and interactive photos of lab models [ bronchial tree] [lung ] Trachea splits into primary bronchi [1] to right and left lung Secondary bronchi [2] to lung lobes [3 on right & 2 on left] Tertiary bronchi [3] to bronchopulmonary segments Bronchioles [4] are branches in each bronchopulmonary segment totals over 6000 terminal bronchiole to respiratory bronchiole to alveolar duct alveolar duct to alveoli * see illustration of alveolus Histology of walls of Bronchial Tree (transition in layers to alveoli) Wall layers are mucosa, submucosa and muscularis Trachea The lining (mucosa) is pseudostratified ciliated columnar "C" shaped hyaline cartilage rings keeps tracea open Bronchi Pseudostratified columnar, ciliated epithelium (becomes shorter) cartilage rings reduced Bronchioles simple ciliated columnar or cuboidal epithelium; no cartilage greater proportion of smooth muscle (act to constrict and dilate)

  See 10 Names Scroll Down 1 primary bronchus 2 secondary bronchus 3 tertiary bronchus 4 bronchiole 5 alveolus 6 trachea 7 larynx 8 thyroid cartilage 9 cricoid cartilage 10 caridac notch

• Lung surfaces, lobes and segments [see surfaces and lobes on Larynx to lung model]
  • Lung surfaces [apex, costal, medial, inferior]
  • Right lung 3 lobes [superior, middle and inferior lobes] see right lung model
  • Left lung 2 lobes [superior and inferior lobes] (cardiac notch [10] on medial surface) [see torso lungs]
  • Lobes subdivided into Bronchopulmonary Segments [See segments and lobes in SkeleTorso right lung
• Alveoli are microscopic gas exchange sacs surrounded by capillaries. [see interactive alveoli on lab model]
• Three types of alveolar cells
  1. Type I Alveolar cells (simple squamous epithelium) for diffusion of gases.
  2. Type II Alveolar cells
     • Thick rounded cells
     • secrete [ surfactant - dipalmitoyl lecithin] which prevents the cohesive and adhesive forces of water from collapsing alveoli
     • Develops in fetus about 8th month
  3. Alveolar macrophage (dust cell)
• Gas exchange in alveoli and respiratory bronchioles
• Lungs located in pleural cavities of thoracic cavity
  • Pleura cavity is lined with parietal pleura
  • Lungs are covered with visceral pleura
  • Pleuras are serous membranes that adhere to one another
  • Therefore intrapleural space between lung and thoracic wall is only a potential space.
  • Mediastinum is cavity of thorax medial to pleural cavities
• Animation of lungs

• Inspiration
  • Diaphragm & external intercostals contract
  • Expand intrapleural space and reduce pressure
  • Atmospheric air, now at higher pressure enters lung
  • Viseral pleura adheres to parietal pleura, expanding lungs as pleural cavities expand.
• Expiration
  • Lung recoil
  • Diaphragm relaxes and is pushed up into pleural space by compression of abdominal muscles
  • Compression of lung expels air
• Animation of lungs
• Respiratory Volumes and Capacities [tidal volume, vital capacity, residual volume]

• Medulla contains Rhythmicity area with both inspiratory & expiratory neurons
• Pons contains the Apneustic area [tweaks medullary centers]
• Pons contains the Pneumotaxic area [limits duration of inspiration]
• Monitored by chemoreceptors that detect CO₂ and O₂ levels.

• Oxygen is tranported around the body by hemoglobin
• Hemoglobin is contained in Red Blood Cells
• Most carbon dioxide is transported within RBC as hydrogen carbonate ion.
• Carbonic anhydrase in RBC accelerates the reaction that forms bicarbonate ion
• The respiratory gasses O₂ and CO₂ diffuse across membranes from their higher partial pressure side to their lower.

• Models [Lobes and surfaces] [Right lung lobes] [Right lung SkeleTorso]
• Interactive model photos: [ larynx model] [ bronchial tree] [Interactive internal right lung] [Interactive alveoli model]
• Head & Neck [sagittal section] [Torso left sagittal section] [right sagittal section, pharynx]
• Torso [ventral cavity organs] [thorax, bronchi, diaphragm] [Closer view trachea]
• Torsos unlabeled [lungs and diaphragm] [big torso's lungs and diaphragm]

• Crossword on Introduction to Respiratory System
• Test your knowledge of respiratory system terms Play Quia!
• Try WebAnatomy at Univ of Minnesota
  • Respiratory System quizzes 1, 2, 3,
  • Web Anatomy Games: respiratory system, upper respiratory, bronchial tree
• Drag & Drop quiz on Larynx to Alveoli

Dynamic Human at McGraw-Hill

Human Anatomy Online

Etymology of Medical Terms

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Revised February 23, 2007
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Comments to:camelet@lakemichigancollege.edu