RESPIRATORY SYSTEM
Chapter 13
Bio 221
RESPIRATORY SYSTEM FUNCTIONS
Gas Exchange (pick-up O2, eliminate CO2)
Filter, Warm & Humidify AirProtectionSpeechRegulate pH
RESPIRATORY SYTEM ORGANIZATION
Upper Respiratory Tract (Outside Thorax)- Nose Pharynx
Lower Respiratory Tract (Inside Thorax)- Larynx Lungs
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Upper Respiratory Tract
Composed of:- the nose- the nasal cavity- the paranasal sinuses- the pharynx (throat)
Conducts, conditions & filters air
UPPER RESPIRATORY TRACT
Nose
- External Nares/Anterior Nasal Aperture (nostril)
- Nasal Cavity
* Hairs & Mucus (Trap debris)
* Ciliated mucosa (conditions air); cilia move mucus down to pharynx
* Divided by nasal septum
* Nasal Conchae Bones (turbulence)
* Olfactory epithelium with receptors (smell)
* Receives tear drainage25-6
Tear Drainage
9
UPPER RESPIRATORY TRACT continued
- Paranasal Sinuses (4)* Bone cavities* Reduce weight; sound resonance* Lined with Mucous Membrane; conditions
air* Empty into Nasal Cavity
- Internal Nares/Posterior Nasal Aperture (Opening between Nasal Cavity & Nasopharynx)
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Pharynx (Throat)- Between Nasal Cavity, Oral Cavity & Larynx- Passageway for Air & Food- Protected by tonsils, mucosa- 3 Divisions
* Nasopharynx* Oropharynx* Laryngopharynx
UPPER RESPIRATORY TRACT continued
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Pharynx
Nasopharynx- Anterior nasal aperture Soft palate (uvula)- Posterior to nasal cavity - Includes Pharyngeal tonsil & Tubal tonsils
(around openings to Auditory tubes)- Air passageway- Soft palate prevents food/water from entering
nasopharynx during swallowing
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Pharynx
Oropharynx- Soft Palate Base of tongue/hyoid bone- Posterior to oral cavity- Includes palatine & lingual tonsils- Shared passageway (air, food, water)
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Pharynx
Laryngopharynx- Base of tongue/hyoid bone Opening to
Esophagus- Continuous with larynx & esophagus- Shared passageway (air, food, water)
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25-19
Lower Respiratory Tract
Composed of- the larynx
- the trachea
- the bronchial tree
- the lungs
Conducts air, conditions air, gas exchange
Lower Respiratory Tract - Larynx
Hyoid bone through cricoid cartilageAir PassagewayPrevents food/water from entering lower
respiratory tractSound production (speech)Supported by cartilage
Glottis is a Slit-like Opening into Larynx;Produces Speech with Vocal Cords
Larynx - Cartilages
• Epiglottis• Covers Glottis (opening of larynx)
• Prevents food from Entering Trachea
• Thyroid Cartilage• “Adam’s Apple”
• Cricoid Cartilage• Inferior, Encircles Vocal Cords
Lower Respiratory Tract - Trachea
Conducts airReinforced with “C”-shaped tracheal
cartilagesNo cartilage posteriorly; allows swallowingExtends from larynx to primary bronchiRuns through MediastinumAnterior to esophagus
Trachea
Lower Respiratory Tract- Bronchial Tree
Branching passageways; Conduct airSupported by cartilagePrimary Secondary TertiaryRight primary bronchus
- more vertical, shorter & wider than left
- aspirated objects enter & lodge
Different branches of bronchial tree serve different lung regions.
Primary bronchi lungs
Secondary bronchi lobes
Tertiary bronchi lung segments
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Bronchial Tree – Terminal bronchiolesStructural Modifications
Ciliated epithelium non-ciliated (macrophages remove particles)
Incomplete cartilaginous rings plates scattered pieces no cartilage
As cartilage , smooth muscle
Respiratory Zone – sites of gas exchange in lungs
Air conduction & gas exchangeThinner epithelium for gas exchangeIncludes:
- Respiratory bronchioles- Alveolar ducts- Alveoli & Alveolar sacs
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Alveoli
Site of most gas exchange (diffusion)Microscopic out-pouchingSimple squamous E.T., supported by thin
elastic basement membraneSource of spongy texture
Alveolar Cells
Type I alveolar cells (squamous epithelial)
- Main site of gas exchange
Type II alveolar cells- Secrete alveolar fluid & surfactant, surface
tension, prevents collapse- Secrete anti-bacterial proteins
Alveolar macrophages (Dust cells)
Fibroblasts (produce reticular & elastic fibers)
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Lungs - Location
Paired (“spongy”) OrgansContain bronchial tree & respiratory zoneWithin pleural cavities; separated by
mediastinumEnclosed & protected by pleura (serous)
- Visceral – surface of lungs- Parietal – attached to thoracic cavity wall
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Lungs – Regions & Surfaces
• Apex (Superior Extension, Above Clavicle)
• Base (Inferior, Rests on Diaphragm)
• Hilum (Vertical slit on Mediastinal Surface)
• Cardiac Notch (Recess on Left Lung)
Lungs – Gross Anatomy
Lobes- Right: superior, middle, inferior- Left: superior, inferior
Fissures- Right: Horizontal, right oblique- Left: left oblique
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Different branches of bronchial tree serve different lung regions.
Primary bronchi lungs
Secondary bronchi lobes
Tertiary bronchi bronchopulmonary segments
Lung LobulesSmallest visible
division of lungsWrapped in elastic
C.T.Contain:
bronchiole & its branches, arteriole, venule, lymphatic vessel
Ventilation (Breathing)Mechanics of moving air in & outDepends on gas moving from high to low pressure
(Boyle’s Law)
Quiet Inspiration- Diaphragm & external intercostals contract- Size of thoracic cavity - Pressure - Air flows in
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Ventilation continued
Quiet Expiration- Nerve impulses cease, diaphragm & ext.
intercostals relax- Size of thoracic cavity - Pressure - Gases flow out
Spirometry
Respiratory Volumes- Tidal Volume (Amount in Single, Relaxed
Breath or Breathing Cycle, 500 ml)- Inspiratory Reserve Volume (Amount
Forcibly Taken in Above TV, 3,000 ml) - Expiratory Reserve Volume (Amount
Forcibly Exhaled after TV, 1,000 ml) - Residual Volume (Always Remains in
Lungs) - Vital Capacity (Max. Amount Exhaled, TV
+ IRV + ERV, 4,500 ml)
RESPIRATION (Gas Exchange)
Occurs in two locations:- External Respiration
* Between Alveoli & Pulmonary Capillaries
* O2 diffuses into blood & CO2 diffuses out
- Internal Respiration* Between Systemic Capillaries & Interstitial
Spaces
* O2 diffuses out of blood & CO2 diffuses in
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RESPIRATORY SYSTEM PHYSIOLOGY continued
- CO2 Transport:
* Bicarbonate Ion (HCO3-) in RBCs
* Attached to Hemoglobin* Plasma
Control of Breathing
Respiratory Regulatory Center- Medulla – sets the basic rate & rhythm
* CO2 changes (pH) act as primary stimulus
- Pons – smooths respiratory pattern
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Control of Breathing
Chemoreceptors - Medulla oblongata monitors CO2 & pH of
CSF- Aorta & Carotid Artery detect changes in
oxygen concentration
Peripheral Chemoreceptors
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