1. General anatomy of respiratory system
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2. The Respiratory System
Cells continually use O2 & release CO2
Respiratory system designed for gas exchange
Cardiovascular system transports gases in blood
Failure of either system
rapid cell death from O2 starvation
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3. Respiratory System Anatomy
Nose
Pharynx = throat
Larynx = voicebox
Trachea = windpipe
Bronchi = airways
Lungs
- upper respiratory tract is above vocal cords
lower respiratory tract is below vocal cords
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4. External Nasal Structures
Skin, nasal bones, & cartilage lined with mucous membrane
Openings called external nares or nostrils
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5. Nose -- Internal Structures
Large chamber within the skull
Roof is made up of ethmoid and floor is hard palate
Internal nares are openings to pharynx
Nasal septum is composed of bone & cartilage
Bony swelling or conchae on lateral walls
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6. Functions of the Nasal Structures
Olfactory epithelium for sense of smell
Pseudostratified ciliated columnar with goblet cells lines nasal cavity
warms air due to high vascularity
mucous moistens air & traps dust
cilia move mucous towards pharynx
Paranasal sinuses open into nasal cavity
found in ethmoid, sphenoid, frontal & maxillary
lighten skull & resonate voice
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7. Pharynx Muscular tube (5 inch long) hanging from skull
skeletal muscle & mucous membrane
Extends from internal nares to cricoid cartilage
Functions
passageway for food and air
resonating chamber for speech production
tonsil (lymphatic tissue) in the walls protects entryway into body
Distinct regions -- nasopharynx, oropharynx and laryngopharynx
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8. Nasopharynx From internal nares to soft palate
openings of auditory (Eustachian) tubes from middle ear cavity
adenoids or pharyngeal tonsil in roof
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9. Oropharynx From soft palate to hyoid bone
fauces is opening from mouth into oropharynx
palatine tonsils found in side walls, lingual tonsil in tongue
Common passageway for food & air
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10. Laryngopharynx Extends from hyoid bone to cricoid cartilage
Common passageway for food & air & ends as esophagus inferiorly
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11. Cartilages of the Larynx
Thyroid cartilage forms Adam’s apple
Epiglottis---leaf-shaped piece of elastic cartilage
during swallowing, larynx moves upward
epiglottis bends to cover glottis
Cricoid cartilage---ring of cartilage attached to top of trachea
Pair of arytenoid cartilages sit upon cricoid
many muscles responsible for their movement
partially buried in vocal folds (true vocal cords)
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12. Larynx Cartilage & connective tissue tube Anterior to C4 to C6
Constructed of 3 single & 3 paired cartilages
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13. Vocal Cords
False vocal cords (ventricular folds) found above vocal folds (true vocal cords)
True vocal cords attach to arytenoid cartilages
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14. Trachea
Extends from larynx to T5 anterior to the esophagus and then splits into bronchi
Layers
mucosa = pseudostratified columnar with cilia & goblet
submucosa = loose connective tissue & seromucous glands
hyaline cartilage = 16 to 20 incomplete rings
open side facing esophagus contains trachealis m. (smooth)
internal ridge on last ring called carina
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15. Trachea and Bronchial Tree
Full extent of airways is visible starting at the larynx and trachea
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16. Histology of the Trachea
Ciliated pseudostratified columnar epithelium
Hyaline cartilage as C-shaped structure closed by trachealis muscle
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17. Bronchi and Bronchioles
Primary bronchi supply each lung
Secondary bronchi supply each lobe of the lungs (3 right + 2 left)
Tertiary bronchi supply each bronchopulmonary segment
Repeated branchings called bronchioles form a bronchial tree
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18. Histology of Bronchial Tree
Epithelium changes from pseudostratified ciliated columnar to nonciliated simple cuboidal as pass deeper into lungs
Incomplete rings of cartilage replaced by rings of smooth muscle & then connective tissue
sympathetic NS & adrenal gland release epinephrine that relaxes smooth muscle & dilates airways
asthma attack or allergic reactions constrict distal bronchiole smooth muscle
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19. Pleural Membranes & Pleural Cavity
Visceral pleura covers lungs --- parietal pleura lines ribcage & covers upper surface of diaphragm
Pleural cavity is potential space between ribs & lungs
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20. Gross Anatomy of Lungs
Base, apex (cupula), costal surface, cardiac notch
Oblique & horizontal fissure in right lung results in 3 lobes
Oblique fissure only in left lung produces 2 lobes
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21. Mediastinal Surface of Lungs
Blood vessels & airways enter lungs at hilus
Forms root of lungs
Covered with pleura
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22. Structures within a segment of Lung
Branchings of single arteriole, venule & bronchiole are wrapped by elastic CT
Respiratory bronchiole
simple squamous
Alveolar ducts surrounded by alveolar sacs & alveoli
sac is 2 or more alveoli sharing a common opening
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23. Cells Types of the Alveoli
Type I alveolar cells
simple squamous cells where gas exchange occurs
Type II alveolar cells (septal cells)
free surface has microvilli
secrete alveolar fluid containing surfactant
Alveolar dust cells
wandering macrophages remove debris
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24. Alveolar-Capillary Membrane
Respiratory membrane = 1/2 micron thick
Exchange of gas from alveoli to blood
4 Layers of membrane to cross
alveolar epithelial wall of type I cells
alveolar epithelial basement membrane
capillary basement membrane
endothelial cells of capillary
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25. Details of Respiratory Membrane
Find the 4 layers that comprise the respiratory membrane
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26. Double Blood Supply to the Lungs
Deoxygenated blood arrives through pulmonary trunk from the right ventricle
Bronchial arteries branch off of the aorta to supply oxygenated blood to lung tissue
Venous drainage returns all blood to heart
Pulmonary blood vessels constrict in response to low O2 levels so as not to pick up CO2 on there way through the lungs
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27. Respiration
Respiration is exchange of primarily oxygen and carbon dioxide between atmosphere and human body
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28. Respiration: Steps Respiration is achieved in four steps
Pulmonary ventilation: Inspiration + Expiration
External respiration: Diffusion across alveolar-capillary membrane
Gas transport: Transport of O2 and CO2
Internal respiration: Exchange between ICF and tissue capillary
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29. Breathing or Pulmonary Ventilation
Air moves into lungs when pressure inside lungs is less than atmospheric pressure
How is this accomplished?
Air moves out of the lungs when pressure inside lungs is greater than atmospheric pressure
Atmospheric pressure = 1 atm or 760mm Hg
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30. Boyle’s Law
As the size of closed container decreases, pressure inside is increased
The molecules have less wall area to strike so the pressure on each inch of area increases.
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31. Dimensions of the Chest Cavity
Breathing in requires muscular activity & chest size changes
Contraction of the diaphragm flattens the dome and increases the vertical dimension of the chest
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32. Quiet Inspiration
Diaphragm moves 1 cm & ribs lifted by external intercostal muscles
Intrathoracic pressure falls and 2-3 liters inhaled
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33. Quiet Expiration Passive process with no muscle action
Elastic recoil & surface tension in alveoli pulls inward
Alveolar pressure increases & air is pushed out
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34. Intra-pleural Pressures
Always subatmospheric (756 mm Hg)
As diaphragm contracts intrapleural pressure decreases even more (754 mm Hg)
Helps keep parietal & visceral pleura stick together and alveoli inflated
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35. Summary of Breathing Alveolar pressure decreases & air rushes in
Alveolar pressure increases & air rushes out
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36. Compliance of the Lungs
Ease with which lungs & chest wall expand depends upon 1. Elastic recoil of lungs &
2. surface tension
Some diseases reduce compliance
tuberculosis forms scar tissue
pulmonary edema --- fluid in lungs & reduced surfactant
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37. Pneumothorax
Pleural cavities are sealed cavities not open to the outside
Injuries to the chest wall that let air enter the intrapleural space
causes a pneumothorax
collapsed lung on same side as injury
Atelectasis: Collapsing of lung due to lack of sufficient surfactant
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38. Airway Resistance
Resistance to airflow depends upon airway size(diameter)
increase size of chest
airways increase in diameter
contract smooth muscles in airways
decreases in diameter
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