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46 Cards in this Set
- Front
- Back
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what are the goals of respiration?
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provide O2 to the tissues, remove CO2 from the tissues
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what are the 4 functional events of respiration?
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(1) pulmonary ventilation (2) diffusion of O2 & CO2 between alveoli & blood (3) transport of O2 & CO2 between blood/body fluids (4) Regulation of respiration
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what is pulmonary ventialtion?
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inflow and outflow of air between atmosphere and alveoli
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what are the anatomical parts of the respiratory system?
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air passageways & pulmonary circulatory system
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what are the types of air passageways?
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conducting airways and respiratory zone
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what are the conducting airways?
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trachea, bronchi, bronchioles
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what are the characteristics of all the conducting airways?
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tubes kept open by combination of (1) rigid structural elements (2) traction from surrounding tissues & (3) pressure gradient across walls
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what are the characteristics of the trachea?
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multiple cartilage rings extend 5/6 way around trachea
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what are the types of bronchi?
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(1) main (2) lobar (3) segmental
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what are the characteristics of bronchi?
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less extensive cartilage plates provide rigidity but allow motion as lungs expand/contract, plates decrease along length of bronchi (gone by bronchioles) and walls are composed of smooth muscle when no cartilage is present
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what are the characteristics of bronchioles?
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no cartilage present, walls of smooth muscle, consist of terminal bronchioles then respiratory bornchioles (both have a few smooth muscle fibers) with respiratory bronchioles have an occasional alveolus
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what are conducting airways?
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includes trachea, bronchi & bronchioles; function of these airways is to lead inspired air to the gas exchange regions of the lung
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what is anatomic dead space?
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a practical definition of the conducting airways, as these airways take no part in gas exchange because they do not have alveoli
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what does the respiratory zone consist of?
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respiratory bronchioles, alveolar ducts, alveoli
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what are the characteristics of alveolar ducts?
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lined with alveoli
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what are the characteristics of alveoli?
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where gas exchange occurs between the lung & the abutting pulmonary/alveolar capillaries; very thin barrier for gas exchange
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what is Fick's Law of Diffusion?
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amount of gas moved is proportional to the area of the membrane it moves across and inversely proportional to the thickness of that membrane
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what is an example of Fick's Law of Diffusion in practice?
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in a large dog, 50-100 sq m. exchange barrier tissue all wrapped closely around blood vessels
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what is the course of the general airflow pattern?
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during breathing, air flows through (1) upper airway (nose, pharynx, larynx) to (2) tracheobronchial tree to the (3) alveoli, where gas exchange occurs beteen the lung and blood stream
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what happens during inspiration?
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air is drawn into the lung by diaphragmatic contraction and rib cage expansion which causes bulk flow of air to the terminal bronchioles. From here, cross-sectional area of the airways is so enormous that forward velocity of the air slows and diffusion of gas is responsible for its movement into the alveoli which is important for issues of particle deposition in the airways
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how is air drawn into the lungs?
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diaphragmatic contraction and rib cage expansion
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what does diaphragmatic contraction & rib cage expansion cause?
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bulk flow of air to the terminal bronchioles
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how doe air move into the alveoli?
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via diffusion of gas because the cross sectional are of the airway is so enormous that forward velocity of air slows
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the diffusion of gas into the alveoli is important in what issue?
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particle deposition in the airways
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what is the function of the nose?
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(1) warm and humidify air (2) particle removal
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how does particle removal occur in the nose?
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(1) hairs at entrance of nostrils filter large particles (>5μm) (2)turbulent precipitation or sedimentation removes more particles; air moving through passageway hits obstructions (conchae/turbinates, septum, pharyngeal wall) causing air to change directions while particles, which are heavier, cannot change directions so strike surfaces becoming entrapped in mucus, etc. these particles in the upper respiratory tract are removed by mucociliary clearance (3) diffusion deposits submicronic partiles in the alveoli where they are removed by alveolar macrophages
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what parts of the respiratory system have mucus and ciliary functions?
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(1) nose (2) trachea (3) bronchus (4) bronchioles
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what are the characteristics of mucus?
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(1) secreted by goblet cells and submucosal glands in tracheobronchial mucosa (2) secreted by apocrine, mucus-secreting (clara) cells lining the respiratory bronchioles (3) two layers: Gel & Sol (4) mucus traps particles, bacteria, viruses, etc
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what secretes mucus in the tracheobronchial mucosa?
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goblet cells & submucosal glands
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what secretes mucus in the respiratory bronchioles?
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apocrine, mucus-secreting (clara) cells
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what are the two layers of mucus?
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Gel and Sol
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what does mucus do in the respiratory system?
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traps particles, bacteria, viruses, etc
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what are the characteristics of cilia?
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(1) ciliated epithelium exists from nasal passage to terminal bronchioles (2) cilia beat in a 'power stroke toward the pharynx [(a) cilia in lungs beat cranially (b) cilia in nose beat caudally (c) continual movement of cilia and gel layer known as the mucociliary escalator (d) particles reaching the pharynx are swallowed, coughed]
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what is the mucociliary escalator?
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continual movement of cilia and gel layer to remove particles and mucus from respiratory system
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what is the function of bronchioles in airway resistance?
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small bronchioles cause greatest resistance to flow of air in disease
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the greatest resistance to flow of air in disease is due to small bronchioles for what reasons?
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(1) small size makes them easily occluded (2) high percentage of smooth muscles in walls cuase them to constrict easily
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what lung sounds might one hear?
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(1) normal breath sounds (2) wheeze (3) crackles (4) multiple sounds
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what are normal breath sounds?
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normal airway and lung sounds heard during quiet breathing; barely perceptible in some animals (cat, horse)
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what are wheezes?
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high-pitched sound due to small airway obstruction or collapse, probably the sound of the sides of the airway vibrating when in close proximity; heard most clearly as a continuous sound on expiration
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what are crackles?
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high-pitched, discontinuous sound heard on inspiration and expiration, although frequently louder during inspiration; sound of air 'bubbling' through mucus plugged airways
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what are other respiratory sounds?
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(1) cough (2) sneeze (3) panting
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what triggers a cough?
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simulation of subepithelial irritant receptors by (1) material on epithelial surface (2) bronchoconstriction (due to allergic reaction, noxious gases, smoke, etc) (3) hyper-responsive when respiratory tract epithelium injured (virus)
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where are subepithelial irritant receptors located?
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(1) most numerous in larynx, trachea, larger bronchi (2) Carina (point where trachea divides into bronchi) especially sensitive to irritants (3) terminal bronchioles, alveoli sensitive to corrosive gas stimuli
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detail the physiology of a cough (step-by-step)
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(1) stimulated subepithelial irritant recpetors send afferent nerve impulse through vagus nerve to brain, triggering and automatic sequence of events (2) air rapidly inspired and trapped in lungs by closing of epiglottis and larynx (3) expiratory muscles and abdominal muscles contract (4) pressure in lungs rises (100 mm Hg) (5) larynx and epiglottis suddenly open, so air under pressure explodes outward (75-100 mph) (6) pressure in lungs (intrapulmonary pressure) exceeds pressure in the airway lumen, so noncartilaginous parts of trachea and bronchi collapse, so air explodes through bronchial and tracheal slits
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what are the characteristics of a sneeze?
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(1) cough applied to the nasal passages (2) stimulus is irritation of nasal passageway (3) afferent nerve signals trigger sneeze reflex (4) physiology is series of reaction similar to cough, but with uvula depressed so air is rapidly pushed through nose
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what are the characteristics of panting?
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(1) function of the respiratory system in temperature regulation (2) respiratory center of any animal that pants responds to usual stimula and to core body temperature (3) heat is dissipated by increasing anatomical dead space ventilation (4) dead-space ventilation is increased by panting that provides cooling via evaporation of water from the mucous membranes of tissues involved (nose, mouth, upper airway)
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