1. Chapter 13 The Respiratory System

2. Organs of the Respiratory system
Nose
Pharynx
Larynx
Trachea
Bronchi
Lungs – alveoli

3. Function of the Respiratory System
Gas exchanges between blood and external environment
Exchange of gasses within lungs in the alveoli
Passageways to the lungs purify, warm, and humidify the incoming air

4. The Nose Only visible part of the respiratory system
Air enters through external nares (nostrils)
Interior is nasal cavity divided by nasal septum

5. Anatomy of the Nasal Cavity
Olfactory receptors located in mucosa on superior surface
Cavity otherwise lined w/ respiratory mucosa
- Moistens air
- Traps incoming foreign particles

7. Anatomy of the Nasal Cavity
Lateral walls have projections called conchae
Increases surface area
Increases air turbulence
within the nasal cavity
Nasal cavity separated from oral cavity by the palate
Anterior hard palate (bone)
Posterior soft palate (muscle)

8. Upper Respiratory Tract
Figure 13.2

9. Paranasal Sinuses Cavities in bones around nose Functions
- Frontal bone
- Sphenoid bone
- Ethmoid bone
- Maxillary bone
Functions
- Lighten the skull
- Resonance chambers for speech
- Produce mucus that drains into the nasal cavity

10. Pharynx (Throat) Muscular passage from nasal cavity to larynx
3 regions of the pharynx
Nasopharynx – superior region behind
nasal cavity
Oropharynx – middle region behind mouth
Laryngopharynx – inferior region attached
to larynx
Oro- & laryngo- are common passageways for air and food

11. Structures of the Pharynx
Auditory tubes enter the nasopharynx
Tonsils of pharynx
- Pharyngeal tonsil (adenoids) in nasopharynx
- Palatine tonsils in oropharynx
- Lingual tonsils at base of tongue

13. Larynx (Voice Box) Routes air and food into proper channels
Helps in speech
8 rigid hyaline cartilages and spoon-shaped flap of elastic cartilage (epiglottis)

14. Structures of the Larynx
Thyroid cartilage
- Largest hyaline cartilage
- Protrudes anteriorly (Adam’s apple)
Epiglottis
- Superior opening of the larynx
- Routes food to the larynx and air toward the trachea
Vocal cords (vocal folds)
- Vibrates air to create sound (speech)
Glottis – opening between vocal cords

16. Trachea (Windpipe) Connects larynx with bronchi
Lined with ciliated mucosa
- Beat in opposite direction of incoming air
- Expel mucus loaded with debris away from lungs
Walls reinforced with C-shaped hyaline cartilage

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

21. Lungs Occupy most of thoracic cavity
Apex is near clavicle (superior)
Base rests on diaphragm (inferior portion)
Each lung is divided into lobes by fissures
Left lung – two lobes
Right lung – three lobes

22. Coverings of the Lungs Pulmonary (visceral) pleura covers lung surface
Parietal pleura lines walls of thoracic cavity
Pleural fluid fills area between layers of pleura to allow gliding; reduces friction

23. Respiratory Tree Divisions
Primary bronchi
Secondary bronchi
Tertiary bronchi
Bronchioli
Terminal bronchioli

24. Alveoli Structure of alveoli Alveolar duct Alveolar sac Alveolus
Gas exchange across membrane of alveoli

26. Respiratory Membrane (Air-Blood Barrier)
Squamous epithelial
Capillaries cover alveoli
Blood not exposed to air

27. Gas Exchange Gas crosses membrane by diffusion
- Oxygen enters the blood
- Carbon dioxide enters the alveoli
Macrophages add protection
Surfactant coats inside alveolus

28. Events of Respiration
Pulmonary ventilation – moving air in and out of lungs
External respiration – gas exchange between blood and alveoli
3. Respiratory gas transport – transport of gases via the bloodstream
4. Internal respiration – gas exchange between blood and tissue cells

29. Pulmonary Ventilation
Mechanical process based on volume changes in the thoracic cavity
Volume changes = pressure changes
Gases go from high low pressure
Two phases
- Inspiration – into lung
- Expiration – leaving lung

30. Inspiration Diaphragm & intercostal muscles contract
Thoracic cavity increases
External air is pulled into the lungs due to an increase in intrapulmonary volume

32. Expiration Passive process As muscles relax, air pushed out
Forced expiration can occur mostly by contracting internal intercostal muscles to depress the rib cage

34. Pressure Differences in Thoracic Cavity
Intrapleural space is always negative (intrapleural pressure)
Differences in lung and pleural space pressures keep lungs from collapsing

35. Nonrespiratory Air Movements
Caused by reflexes or voluntary actions
Examples
Cough and sneeze – clears lungs of debris
Laughing
Crying
Yawn
Hiccup

36. Respiratory Volumes and Capacities
Normal breathing 500 ml of air each breath (tidal volume [TV])
Many factors that affect respiratory capacity
- Size
- Sex
- Age
- Physical condition
Residual volume of air – after exhalation, about 1200 ml of air remains in the lungs

37. Respiratory Volumes and Capacities
Inspiratory reserve volume (IRV)
Extra air forcibly taken in over tidal volume
Usually between ml
Expiratory reserve volume (ERV)
Amount of air that can be forcibly exhaled
~ 1200 ml

38. Respiratory Volumes and Capacities
Residual volume ~ 1200 ml
Air remaining in lung after expiration
Vital capacity
The total amount of exchangeable air
Vital capacity = TV + IRV + ERV
Dead space volume
= Air in conducting zone; never reaches alveoli
= About 150 ml
Functional volume - Usually ~ 350 ml
Air that actually reaches the respiratory zone
Spirometer – tool that measures respiratory capacities

39. Respiratory Capacities