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132 Cards in this Set
- Front
- Back
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What are the subdivisions of the respiratory system?
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- Conducting portion
- Respiratory portion |
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What is the function of the conducting portion of the respiratory system?
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- Conditions air
- Transports air to more distal respiratory passages |
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What is the characteristic structure in the respiratory portion of the respiratory system?
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Alveoli - thin-walled structures where gas exchange occurs between inhaled air and blood
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Clinically, how is the respiratory system divided? Why?
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- Upper Respiratory Tract
- Lower Respiratory Tract - Based on infectious conditions |
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What are the sites of upper respiratory infections?
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- Nasal
- Oral - Middle ear cavities - Paranasal sinuses - Pharynx |
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What are the sites of lower respiratory infections?
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- Larynx
- Trachea - Lungs |
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What are the primary functions of the respiratory system?
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- Air conduction
- Gas exchange |
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What happens during air conduction?
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- Air conditioning: humidification and warming of air
- Removal of foreign substances |
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What happens during gas exchange?
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- Occurs in alveoli
- Exhaled air flows in reverse |
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What are the secondary functions of the respiratory system?
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- Modulation or production of chemical messengers (angiotensin I to angiotensin II)
- Speech sound production - Regulation of acid base balance (in cooperation w/ kidneys) |
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What is the term for the conducting passages located externally to the lungs?
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Extrapulmonary passages
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What is the term for the conducting passages located within the lungs?
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Intrapulmonary passages
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What lines the air conducting passages? Why is this important?
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- Mucosa - contains lymphatic tissue and other defense related cells
- Important because they communicate with the external environment |
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What are the extrapulmonary passage structures?
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Conducting passages external to the lung
- Nasal cavities - Paranasal sinuses - Nasopharynx - Oropharynx - Larynx - Trachea |
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What happens in the nasal cavities?
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- Air is warmed, moistened, and filtered
- Olfaction - detection of odorant molecules |
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Through what does air enter the nasal cavities? What lines this structure?
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Nasal Vestibules - lined w/ stratified squamous keratinized epithelium which contains stiff hairs called Vibrissae
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What kind of epithelium lines the nasal vestibules?
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Stratified squamous keratinized epithelium
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What is the term for the stiff hairs in the nasal vestibule?
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Vibrissae
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What kind of epithelium lines the nasal cavities? What kind of cells are in here?
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Pseudostratified ciliated columnar epithelium containing goblet cells = Respiratory Epithelium
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What is the configuration of the Respiratory Epithelium?
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Pseudostratified ciliated columnar epithelium containing goblet cells
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What covers the apical surface of the Respiratory Epithelium? Function?
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- Bilayer of mucus (external) and serous fluid (internal)
- Traps particulates in the air in the external layer of mucus (smoking and other irritants can reduce the effectiveness of this function) |
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What moves the mucus layer on the apical surface of the Respiratory Epithelium?
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The underlying serous fluid transports the mucus
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What moves the serous layer on the apical surface of the Respiratory Epithelium?
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Moves by beating of cilia embedded within it
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What ultimately happens to the mucus on the apical surface of the Respiratory Epithelium?
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Either swallowed or expectorated (ejected by coughing) through the oral cavity
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What is the term for the ciliary driven mucous cleaner?
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Mucociliary Escalator
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What is in the underlying lamina propria of the nasal vestibule?
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- Seromucous glands
- Extensive vascular plexus |
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What is the function of the extensive vascular plexus within the underlying lamina propria?
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Blood passing through warms the inspired air
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What is responsible for warming the inspired air?
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Blood passing through the extensive vascular plexus within the underlying lamina propria
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What is the nasal cavity mucosa attached to?
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Firmly attached to the underlying periosteum by collagen fibers within the lamina propria
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What kind of mucosa is located in the superior portion of the nasal cavity? What kind of epithelium is it covered by?
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Olfactory Mucosa - covered by Olfactory Epithelium
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What kind of epithelium is the Olfactory Epithelium?
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Pseudostratified columnar epithelium containing Olfactory Cells
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What kind of cells are Olfactory Cells? Function?
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- Bipolar neurons that have an axon at their base and a knob-like olfactory vesicle at apex containing primary cilia
- Detects odors |
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What kind of cells are in the Olfactory Epithelium?
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- Olfactory Cells
- Supporting, basal (stem) and brush cells |
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What is in the lamina propria of the olfactory mucosa?
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- Axon bundles
- Serous Olfactory Glands |
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What is produced by the olfactory glands? Function?
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- Fluid containing odorant binding protein
- Binds to odorants and together they bind to Odorant Receptors on cilia of olfactory cells |
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What happens when an odorant binds to the odorant receptors?
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- Binding activates gated Na+ channel
- Causes ion influx that generates an AP |
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What color is the olfactory mucosa? Why?
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- Yellow-brown
- Pigment contained in epithelium and glands |
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What lines the paranasal sinuses?
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Thinner version of respiratory mucosa (pseudostratified ciliated columnar epithelium)
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What lines the nasopharynx?
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- Respiratory mucosa (pseudostratified ciliated columnar epithelium)
- Stratified squamous non-keratinized |
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Where is the lymphatic tissue in the nasopharynx?
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- Abundant in lamina propria
- Accumulates superiorly as Pharyngeal Tonsil = Adenoids |
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What are the Adenoids?
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Pharyngeal Tonsils = lymphatic tissue that accumulates superiorly in nasopharynx
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What does the mucosa of the nasopharynx adhere to?
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Nasopharynx
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When does the larynx close the airway?
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During swallowing and while producing speech sounds
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What supports the laryngeal passageway?
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- Hyaline cartilage
- Elastic cartilage - Connected by ligaments - Moved by skeletal muscles |
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What lines the larynx?
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Respiratory mucosa (pseudostratified ciliated columnar epithelium)
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What covers the epiglottis and the vocal fold?
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Stratified squamous non-keratinized
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What are the characteristics of the superficial layer of the vocal fold?
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Lamina Propria is poorly vascularized, lacks lymphatic vessels, and has few elastic fibers
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What is Reinke's Space?
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Potential space between the vocal ligament and the overlying mucosa that can collect fluid
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What is the function of Reinke's Space?
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Facilitates vocal cord vibration
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What happens if Reinke's Space collects fluid?
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Hoarseness during chronic inflammation of vocal cords
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What are the characteristics of the vocal fold core?
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- Stiff
- Consists of remaining lamina propria - Vocal ligament and vocalis muscle |
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What kind of cells are unusually abundant in the larynx lamina propria?
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Mast cells
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What happens in Croup?
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Inflammation of the mucosa in the larynx (laryngitis), trachea, and bronchi
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What are the layers in the wall of the trachea?
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1. Mucosa
2. Submucosa 3. Cartilage 4. Adventitia |
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What kind of epithelium covers the mucosa of the trachea?
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Respiratory Epithelium (pseudostratified ciliated columnar epithelium)
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What are the characteristics of the basement membrane in the trachea?
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Appears thick d/t expanded reticular layer
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What is in the submucosal layer of the trachea?
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- Loose CT
- Separated from mucosa by elastic membrane - Contains seromucous glands - Contains abundant lymphatic tissue |
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What is the location of the seromucous glands of the trachea?
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Submucosal layer
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Where is the lymphatic tissue in the trachea?
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Abundant in the lamina propria and the submucosa
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What supports the tracheal airway?
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C-shaped hyaline cartilages
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What bridges the free end of the C-shaped hyaline cartilages in the trachea?
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Smooth muscle and fibroelastic tissue
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What are the components of the intrapulmonary passages?
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- Bronchi (except for initial segment)
- Bronchioles |
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What happens as the passages of the bronchiole branches become smaller in diameter?
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- Organization of wall becomes less complex
- At certain levels, some wall components (cartilage and glands) disappear - Height of epithelium is progressively reduced |
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What are the layers of the wall of the bronchi?
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- Mucosa
- Muscularis - Submucosa - Cartilage - Adventitia |
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What kind of epithelium covers the bronchial mucosa?
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Respiratory Epithelium (height is reduced as you get deeper)
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What are the characteristics of the muscularis layer of the bronchi? Location?
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- 2 discontinuous layers of spiraling smooth muscle
- Lies between the lamina propria and the submucosa |
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Where are the seromucous glands of the bronchi?
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Lamina propria and submucosa
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What is unique about the extrapulmonary portion of the primary bronchi?
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They have C-shaped cartilage rings
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What is unique about the intrapulmonary portion of the primary bronchi?
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There are irregular shaped cartilage plates
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What is in the adventitia of the bronchi wall?
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Moderately dense CT - continuous w/ surrounding lung parenchyma
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What is the average diameter of the bronchioles?
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1 mm (5 mm - 0.3 mm)
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What do the walls of the bronchioles lack?
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- Cartilage plates
- Seromucous glands |
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What kind of epithelium covers the mucosa of the bronchioles?
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Ranges from ciliated simple columnar to simple cuboidal epithelium
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What kind of cells can be present within the epithelium over the mucosa of the bronchioles?
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- Goblet cells occasionally
- Clara cells - columnar cells w/ dome-shaped apex and short microvilli |
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What kind of cells are characteristic of the bronchiole epithelium?
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Clara cells - columnar cells w/ dome-shaped apex and short microvilli
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What do the Clara Cells contain in the bronchioles? Function?
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- Secretory granules and their product, Clara Cell Protein (CC16/CC10)
- Protects the bronchiolar epithelium via anti-inflammatory action - Also contain abundant smooth ER w/ cytochrome that degrades toxins - May also produce a surfactant-like molecule - Release Cl- via a cGMP regulated ion channel |
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What is external to the lamina propria in the bronchioles?
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Loose network of smooth muscle oriented in helical configuration
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What kind of lymphatic tissue is in the the bronchi and bronchioles? Which layer?
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BALT - found in mucosa
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What are the most distal bronchiole branches called? Average diameter?
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Terminal Bronchioles - 0.5 mm
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What is the end of the conducting portion of the lung?
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Terminal Bronchioles
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What are the clinical conditions affecting intrapulmonary conducting airways?
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- Chronic Bronchitis
- Asthma - Cystic Fibrosis - Bronchial Carcinoma |
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What causes Chronic Bronchitis? Outcome?
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- Caused by repeated damage to mucosa
- Hypertrophy and/or hyperplasia of mucous glands and smooth muscle leads to wall thickening |
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What causes Asthma? Outcome?
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- Hyperresponsiveness of airway triggered by repeated antigen exposure or abnormal autonomic regulation of airway function
- Leads to airway wall inflammation, hypersecretion of thick bronchial mucus, and vasodilation of bronchial microvasculature - Prolonged smooth muscle contraction leads to bronchoconstriction during exhalation |
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What causes Cystic Fibrosis?
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- Alteration of Cl- ion channel protein (CFTR) on submuocsal gland cell causes defective Cl- transport and increased Na+ absorption --> more viscous mucus that traps bacteria
- Production of a thick mucus by the epithelium causes the airways to be blocked - Thick mucus interferes w/ proper function of mucociliary escalator - Followed by bacterial infections |
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What protein is mutated in Cystic Fibrosis? Location?
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CFTR = Cystic Fibrosis Transmembrane Conductance Regulator (Cl- ion channel protein)
- Found in submucosal gland cells - Also found in pancrease excorine cells and sweat gland ducts |
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What causes Bronchial Carcinoma?
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Squamous metaplasia resulting from chronic irritation or from small granule (neuroendocrine) cells in epithelium
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What are the components of the respiratory passages?
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- Respiratory bronchioles
- Alveolar ducts - Alveolar sacs - Alveoli |
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What does a terminal bronchiole branch into?
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Several Respiratory Bronchioles
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What kind of epithelium lines the respiratory bronchioles?
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Simple cuboidal epithelium, eventually becomes non-ciliated
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What kind of cells are found in the respiratory bronchiole epithelium?
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Clara cells - predominate more in distal portions
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What are the out-pouchings of the respiratory bronchiole wall?
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Alveoli - sites of gas exchange
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What structure is found between adjacent alveoli?
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Small knob-like septum containing:
- Smooth muscle cells - Reticular fibers - Elastic tissue |
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What does the opening to the alveoli contain?
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Fibers of elastin and type III collagen, but LACK smooth muscle
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What surrounds and interconnects the respiratory passages?
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Network of fine elastic fibers
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How many alveoli are there per lung?
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150-300 million small, thin walled chambers called Alveoli
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What kind of epithelium lines alveoli?
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Alveolar Epithelium:
- Squamous type I alveolar cells or Pneumocytes (95% of surface area) - Cuboidal type II alveolar cells or Pneumocytes (5% of surface area) |
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How are Type I Pneumocytes related? What kind of epithelium?
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- Connected to adjacent cells by occluding junctions
- Squamous epithelium |
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What is the function of type II Pneumocytes? What kind of epithelium?
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- Produce, reabsorb, and recycle components of pulmonary surfactant
- Cytoplasm contains apical secretory granules called Lamellar Bodies - Cuboidal epithelium |
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What are Lamellar Bodies and where are they found?
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- Secretory granules for pulmonary surfactant
- Found in cytoplasm on apical side of Type II (cuboidal) alveolar cells / pneumocytes |
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How does the number of Type I (squamous) and Type II (cuboidal) pneumocytes compare? How much alveolar surface area do they take up?
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- Equal amounts of type I and II cells (if not more type II)
- Type I cells occupy 95% of alveolar surface area - Type II cells only occupy 5% of alveolar surface area |
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Besides the Type I and II Pneumocytes, what other cells are found in the alveolar epithelium?
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Brush cells
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What does the alveolar septum contain?
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- Plexus of continuous capillaries surrounded by fibers of elastin and type III collagen
- Macrophages, lymphocytes, mast cells, and fibroblasts |
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What are the openings in the alveolar septum?
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Alveolar Pores
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What kind of cell becomes a "dust cell" in the alveoli? How?
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- Some macrophages migrate between adjacent Type I cells and enter the alveolar lumen
- Become alveolar macrophages / dust cells |
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What is the function of alveolar macrophages / dust cells?
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- Phagocytize particulates and bacteria
- Aid type II cells in phagocytosis of surfactant |
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What are the components of the blood-air barrier?
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- Pulmonary surfactant
- Type I pneumocyte - Fused basement membranes - Capillary endothelial cells |
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What are the components of pulmonary surfactant?
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Phospholipids:
- Phosphotidylcholine - Phosphotidylglycerol Proteins: - Surfactant Proteins A, B, C, and D Antioxidants |
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What is the organization of the lipids and proteins in pulmonary surfactant?
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Lipids flot on layer of proteins
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What happens following heart failure and pulmonary congestion?
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- RBCs extravasate into alveoli
- Engulfed by macrophages that stain positively for iron content = Heart Failure Cells |
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What are Heart Failure Cells?
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- Macrophages that have engulfed the RBCs that have extravasated from the alveoli
- Causes macrophages to stain positively for iron content |
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What are the clinical conditions that affect the respiratory passages?
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- Emphysema
- Acute Respiratory Distress Syndrome - Interstitial Fibrosis - Infections - Lung Cancer |
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What are the characteristics of Emphysema?
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- Progressive destruction of alveolar septa
- Leads to enlarged air spaces - Decreased surface area available for gas exchange |
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What happens to the amount of elastic tissue in Emphysema? Why?
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Decreased elastic tissue d/t inhibition of α1-antitrypsin activity that protects elastic fibers from degradation by proteases
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What is the function of α1-antitrypsin?
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Protects elastic fibers from degradation by proteases in the lung (inhibited in Emphysema)
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What parts of the respiratory system are involved in Emphysema?
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- Just the respiratory bronchiole
- Or all parts of the pulmonary acinus (region of the lung supplied with air from one of the terminal bronchioles) |
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What are the forms of Chronic Obstructive Pulmonary Disease?
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- Asthma
- Chronic bronchitis - Emphysema |
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What are the characteristics of COPD?
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Decreased airflow in individuals w/ normal or increased total lung and forced vital capacity combined w/ decreased forced expiratory volume
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What happens in Acute Respiratory Distress Syndrome?
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- Air-blood barrier is compromised by toxins, infectious agents, or trauma
- Fluid leaks from capillaries causing pulmonary edema - Fibrin and cell debris accumulate in alveolar lumen inhibiting surfactant function |
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What causes Acute Respiratory Distress Syndrome? What does this lead to?
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- Toxins, infectious agents, or trauma compromise the air-blood barrier
- Leads to chronic fibrosis of distal airways |
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What causes Interstitial Fibrosis?
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Progressive condition involving increased collagen and elastin production by fibroblasts within inter-alveolar septum
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What does Interstitial Fibrosis lead to?
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Accumulation of fibrous CT within septum impededs gas exchange leading to hypoxia
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What is Interstitial Fibrosis associated with?
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Accumulation of inhaled particulates such as silica, coal dust, or asbestos within the septal macrophages
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What causes Pneumonia?
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- Toxins from bacterial and viral infections stimulate an inflammatory reaction in lung resulting in pneumonia
- Fluid accumulates in alveoli and reduces amount of lung parenchyma available for gas exchange |
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What cells can lung cancer originate from?
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Cells lining the conducting passageways or the distal airways
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What is a "mucosa"?
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Lining membrane of cavities that have a connection to the exterior of the body
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What are the functions of a mucosa?
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- Immunological and physical barrier
- Source of secretory products - Selective absorptive interface |
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What are the components of a mucosa?
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- Epithelium (at surface)
- Lamina Propria (a CT layer that supports the epithelium) |
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In what disease are the cilia of the respiratory epithelium defective?
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Primary Ciliary Diskinesias (e.g., congenital immotile cilia or Kartagener's syndrome)
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What kind of cells are found in Respiratory Epithelium?
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- Columnar cells
- Goblet cells - Basal cells - Small granule cels - Brush cells |
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What kind of cells are found in Olfactory Epithelium?
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- Olfactory cells
- Supporting cells - Basal cells - Brush cells |
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What is a pulmonary lobule?
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Terminal bronchiole and the lung tissue it supplies
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What is a pulmonary acinus?
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Portion of the lung supplied by a respiratory bronchiole
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