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155 Cards in this Set
- Front
- Back
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Function of the conducting zone
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Moves air from atmosphere into lungs
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Upper and lower boundaries of conducting zone
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Nose/mouth to lungs
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What allows passive exhalation?
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Normal elastic recoil of the airways
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Last structures in airway
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Alveoli
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Respiratory zone
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alveoli - where effective excahgne of gases between air and blood in pulmonary capillaries occurs
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Two tracts in conducting zone
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Upper respiratory tract & lower respiratory tract
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Upper respiratory tract regions
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Nasal cavity
Nasopharynx Oropharynx |
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Lower respiratory tract regions
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Larynx
Trachea Bronchi Bronchioles Terminal bronchioles |
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Why does gas exchange occur only in the alveoli
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b/c gas exchange depends on diffusion, which is effective only over very short distances
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series of structures comprising alveoli
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respiratory bronchioles
alveolar ducts and sacs individual alveoli |
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how thin are the walls of pulmonary capillaries?
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??
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4 key functions of respiratory system
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Gas exchange
Ventilatory support Conditioning of air Support of olfaction, phonation, BP regulation and hormone clearance |
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Ventilatory support
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Maintaining open (low resistance) airways so that air flows easily
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Conditioning of air
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Warms to body temperature, humidified and purified of particulates
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Where in the respiratory system is air normally sterile?
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Alveoli
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Vibrissae
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Hairs in nasal vestibule
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Function of vibrissae
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Help filter out particulate matter
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Function of nasal turbinates
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Increase mucosal surface area
Generate turbulence in the air flow |
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What structures are responsible for expelling trapped particles
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cilia
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2 things that humidify and warm air
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Glandular secretions keep mucosal surfaces wet
Submucosal vascular network serve to humidify and warm air |
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2 layers of nasal cavity MUCOSA
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Epithelium
Lamina propria |
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Type of epithelium found in nasal cavity
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Ciliated pseudostratified columnar epithelium
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Respiratory epithelium
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Ciliated pseudostratified columnar epithelium
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3 MAJOR cell types in nasal cavity epithelium
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Ciliated columnar cells
Goblet cells Basal cells |
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2 MINOR cell types in respiratory epithelium
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Brush cells
Small granule cells (diffuse neuroendocrine cells) |
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Function of ciliated columnar cells
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Coordinated beating of cilia moves particulates in one direction – toward the pharynx
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Appearance of cilia in H&M
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Dense eosinophilic line
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% of each of the major respiratory epithelial cells
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30% each
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Goblet cells – structure & function
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Unicellular glands, secrete mucinogen
Secretions trap particulate |
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Which respiratory epithelial cells are stem cells?
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Basal cells
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Are basal cells normally found at epithelium surface?
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NO
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Columnar cells with blunt microvilli in respiratory epithelium
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Brush cells
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Brush cells are frequently in contact with _____
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Afferent nerve endings
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Small-granule cells in the respiratory epithelium belong to which system
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Diffuse neuroendocrine system (DNES)
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Secretions from small-granule cells are released into where?
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Lamina propria
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3 characteristics of nasal cavity lamina propria
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Highly vascular
Seromucous glands Frequent lymphoid elements |
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Cause of swollen mucosa in nasal cavity during inflammation
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Inflammation cuases vellels in lamina propria to become “leaky”
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Function of seromucous glands in lamina propria of nasal mucosa
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Supplement the secretions of goblet cells
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Frequent lymphoid elements in lamina propria of nasal mucosa
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Nodules
Mast cells Plasma cells |
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Function of frequent lymphoid elements in nasal mucosa
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Protect against inhaled antigens
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What does the nasal mucosa rest on?
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Bone or cartilage
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Mucociliary escalator
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Denser mucous traps most of the particulate matter and slides along slipperier, less viscous layer
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3 antimicrobial factors found in serous components of nasal mucus
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IgA
Lysozymes Lactoferrin |
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Location of olfactory region of nasal cavity
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Roof of nasal cavity
Superior concha Upper septum |
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3 important differences in cell types in olfactory epithelium,
compared to respiratory epithelium |
No goblet cells
Olfactory cells (bipolar neurons) Sustentacular cells |
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Olfactory cells
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Bipolar neurons
Apical vesicles Non-motile cilia Odor-binding proteins that act as olfactory receptors found on cilia |
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Axon of olfactory cell arises from ___ and joins the _____
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Axon of olfactory cell arises from the BASAL REGION OF THE CELL and joins the OLFACTORY NERVE (CN I)
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Function of sustenacular cells
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Provide support for the olfactory receptor cells
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What are Bowman’s glands?
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Serous glands whose secretions act as solvent for odiferous molecules
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Where are Bowman’s glands found?
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Lamina propria of olfactory region of nasal cavity
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Mucosa of olfactory region rests on ____
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Bone
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4 paranasal sinuses
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Ethmoid
Frontal Sphenoid Maxillary |
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Mucosa of paranasal sinuses
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Pseudostratified epithelium with numerous goblet cells
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Function of larynx
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Responsible for phonation
Guards the tracheo-bronchial tree from particulates |
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Epithelium of larynx
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Psuedostratified, except over true vocal folds, where it becomes non-keratinized stratified squamous
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Layers of trachea
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Mucosa
Submucosa Adventitia |
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Describe trachea and extrapulmonary bronchi mucosa
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Respiratory epithelium
Lamina propria: - v. thick basement membrane - loose CT with numerous WBCs - BALT |
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Describe trachea & extrapulmonary bronchi submucosa
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Substantial layer in trachea
Somewhat dense irregular CT Many mucous and seromucous glands |
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Describe adventitia of trachea and extrapulmonary bronchi
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C-shaped rings of hyaline cartilage – ends attached by smooth muscle
Loose-to-dense irregular CT external to the cartilage |
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Function of C-shaped rings in trachea and extrapulmonary bronchi
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Keep airway open
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Age related changes in trachea/bronchi adventitia
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Progressive calcification of the hyaline cartilage
Replacement of smooth muscle attachments by fibrous CT |
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Bronchial tree series
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Trachea --> primary bronchi --> secondary bronchi --> segmental bronchi -->-->--> bronchioles
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Broncho-pulmonary segment
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Segmental bronchus and anatomically discrete part of the lung to which it delivers air
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How many broncho-pulmonary segments normally in human lungs?
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18 total
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Layers of bronchus
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Mucosa
Smooth muscle Cartilage |
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What makes bronchus capable of constriction/dilation?
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Smooth muscle layer between mucosa and cartilage
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Describe cartilage in bronchus
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Discontinuous cartilage plates
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When does cartilage disappear in trachea-bronchial tree?
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Bronchioles
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3 cell types found in epithelium of normal bronchiole
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Ciliated cells
Goblet cells Clara cells |
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What maintains airway patency in bronchioles
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Elasticity of surrounding alveolar walls pulls outward on bronchiole
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Clara cells
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Non ciliated columnar cells with dome-shaped apical surface
Metabolically active Secrete lipoprotein that prevents walls of small airways from sticking together Stem cells for epithelium |
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Terminal bronchiole
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last bronchiole in which no gas exchange occurs
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diameter of terminal bronchiole
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typically 0.5 mm diameter
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terminal bronchioles mark end of _____
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conducting zone
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terminal bronchioles branch into ____
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respiratory bronchioles
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functional characteristic of respiratory bronchioles
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some alveoli bud off their walls, facilitating gas exchange
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pulmonary acinus
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terminal bronchiole and lung tissue that it aerates
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role of elastic fibers
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provide essential resiliance and structural support for airways by keeping wall tensions uniform around & btw airways as lung volume changes with breathing
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2 factors regulating amount of mucus secretion & viscosity
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Autonomic nerves
Local factors |
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Parasympathetic stimulation via _____ receptors stimulates ________
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Parasympathetic stimulation via MUSCARINIC CHOLINERGIC RECEPTORS stimulates both SEROUS and MUCOUS secretions
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Atropine
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Muscarinic cholinergic antagonist routinely given before surgery to “dry” the airway
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Mucous effects of defect in CFTR gene (as with CF)
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Production of extremely thick mucous
- impaired Cl- transport - impaired fluid secretion of bronchial glands Cannot be effectively removed by cilia |
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Consequence of continual presence of irritants
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narrowed airways and reduced airflow
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how does wall layer of respiratory bronchioles differ from that of terminal bronchioles
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alveoli interrupt smooth muscle layer
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where does bronchiolar epithelium end?
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At alveolar ducts and sacs
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individual alveoli are separated by _____
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interalveolar walls or septa
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alveolar knob
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CT thatreinforces interalveolar walls at luminal tip
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8 constituents of alveolar wall
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Type I cell
Type II cell capillary fibroblasts Pore of Kohn macrophages thin wall thick wall |
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type I cell
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squamous epithelial cell
v. attenuated cytoplasm joined to other type I and type II cells by tight junctions |
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type II cell
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large, cuboidal cell
apical sytoplasm contains lamellar bodies of surfactant may be stem cells for type I cell |
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alveolar wall capillary structure
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continuous type
derived from pulmonary circulation (branches of pulmonary artery) |
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functions of alveolar wall capillaries
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gas exchange
conversion of angiotensin I to angiotensin II synthesis/degradation of hormones |
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alveolar wall fibroblast function
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source of elastic and colagen fibers that keep bronchioles open during forced air flow
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Pore of Kohn
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small pore in septum
equilibrates pressure between adjacent alveoli |
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macrophages in septum & lumen of alveoli
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phagocytose inhaled particulates not trapped in mucous layers of URT
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main function of thin alveolar wall
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gas exchange
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main function of thick alveolar wall
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provides structural stability
accomodate limited amount of additional ISF during edema |
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Type I cell, aka:
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type I pneumocyte
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how much of the cardiac output does pulmonary circulation carry?
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all of it
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how do pulmonary arteries differ from systemic arteris
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thinner walls than systemic arteries of the same diameter
due to the lower pressure of the pulmonary circulation |
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Do pulmonary veins parallel pulmonary arteries?
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NO
pulmonary veins travel between pulmonary lobules so that venous blood does not lose its oxygen to the incoming, deoxygenated arterial blood |
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primary function of pulmonary lymphatics
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critically important in keeping lungs dry
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function of bronchial circulation
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nutrient blood supply to the blroncial parenchyma
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where are bronchial arteries and veins found?
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adventitial of bronchi
bronchial arteries arise from branches of the aorta |
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describe right-to-left shunt in normal human heart
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bronchial venous blood drains into pulmonary veins, without becoming oxygenated first, and is therefore delivered to the LV
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normal distance from alveolar air to capillary blood is less than
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1 micron
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2 examples of pathologies that increase distance from alveolar air to capillary blood
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pulmonary edema (excess ISF thickens alveolar wall)
abnormal stimulation of Type II cell production (Type II dominance over Type I in alveolar cell walls) |
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Functional residual capacity
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volume of air in lungs at end of normal expiration
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Tidal volume
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volume of air in normal breath
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Expiratory reserve volume
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volume of air at end of forced expiration subtracted from volume of air at end of normal expiration
FRC - RV = ERV |
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residual volume
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volume of air left in lungs at end of forced respiration
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inspiratory reserve volume
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difference between total lung capacity and lung volume at end of normal inspiration
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vital capacity
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difference between total lung capacity and residual volume
aka: difference between forced inspiration and forced expiration volumes |
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what is the difference between vital capacity and forced vital capacity
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forced vital capacity is measured clinically by inhaling as much as possible and then exhaling as fast and forcibly as possible
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FEV1
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forced expiratory volume within in the first second of exhalation
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Under what circumstances are
FEV1 and FEV1/FVC ratio characteristically reduced? |
obstructive pulmonary disease
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normal value of FEV1
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80% of FVC
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lung volumes that can be measured with spirometry
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tidal volume
expiratory reserve volume vital capacity & forced vital capacity forced expiratory volume in 1 second inspiratory reserve volume as TV and ERV subtracted from VC |
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lung volumes that cannot be measured with spirometry
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reserve volume
forced reserve volume total lung capacity (air that is not exhaled) |
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lung volume of 6 ft male at end of normal expiration
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2.4 L
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lung volume of 6 ft male at end of normal inspiration
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2.9 L
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forced respiratory capacity =
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lung volume at the end of normal expiration
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normal tidal volume
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500 mL/breath
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respiratory frequency abbrev.
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f
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respiratory frequency =
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number of expirations per minute
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total ventilation
abbreviation definition typical value |
total ventilation (VE)
= total volume of air expired per minute e.g.: 500 mL/breath * 12 breaths/min = 6 L/min |
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dead space volume
abbreviation definition typical value |
dead space volume (VD)
volume of ambient air (still O2-rich) expired at the beginning of each exhalation, never having reached respiratory zone VD = 150 mL |
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alveolar ventilation
abbrev. definition equation value |
alveolar ventilation (VA)
volume of alveolar air expired per minute VA = (VT-VD)*f = 4.2 L/min |
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why does alveolar ventilation matter?
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alveolar air is what participates in gas exchange
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definitions of lung volumes are based on ____ air, NOT ____ air
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definitions of lung volumes are based on EXPIRED air, NOT INSPIRED air
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4 factors causing difference in expired vs. inspired air volume
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temperature (expired volume bigger)
humidity (expired volume bigger) CO2 (expired volume bigger) O2 (expired volume SMALLER) |
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which is bigger, expired or inspired volume?
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expired
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inspired volumes are usually measured under which conditions?
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ATPD
ambient temperature and pressure, dry |
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expired volumes are usually measured under which conditions?
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BTPS
body temperature and pressure, saturated |
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What is STPD
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standards temperature (O*C) and pressure (760 mmHg), dry (0% humidity)
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standard temperature in pulmonary medicine
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O*C = 273 K
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which is usually larger, O2 consumption or CO2 production?
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O2 consumption > CO2 production
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O2 consumption = rate at which _____
= rate of _____ |
O2 consumption
= rate at which O2 is taken up from the alveolar air into the blood = rate of O2 use by tissues |
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CO2 production = rate at which ____ = rate of ____
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CO2 production
= rate at which CO2 is added to alveolar air from the blood =rate of Co2 production by body tissues |
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normal O2 consumption and CO2 production values at rest
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VO2 = 250mL O2/min
VCO2 = 200 mL CO2/min |
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repiratory quotient (RQ) =
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RQ = CO2 production/O2 consumption, per unit of time
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normal RQ range
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0.7 to 1.0
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what does RQ depend on?
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relative amounts of carbs, proteins and fats being metabolized
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If only carbs were being metabolized and only by ox phos, what would the RQ be?
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1.0
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expressed under STPD conditions, which is larger, inspired or expried volume?
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inspired
because O2 consumption > CO2 production |
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normal percentages of O2 and CO2 in ambient air
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21% O2
0.04% CO2 |
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how much water vapor is formed per minute to humidify inhaled air?
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300 mL/min
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Percentage of O2 in arterial blood
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20 Vol %
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percentage of O2 in venous blood
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15 vol %
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3 reasons why FaO2 is less than 21%
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oxygen is consumed
CO2 is added - dilutes oxygen H2O vapor is added - dilutes oxygen |
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ideal gas law
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PV = nRT
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Pressure never ____; pressure only ____
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Pressure never sucks; pressure only pushes.
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____ cm H2O = 1 mmHg
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1.36 cm H2O = 1 mmHg
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Effect of altitude
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barometric pressure decreases with altitude because air gets less dense
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T/F: dry atmospheric air has the same composition, no matter what the altitude
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True
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