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Anatomy and PhysiologyAnatomy and Physiology
[Tab 2]
Respiratory SystemRespiratory System
1910.134(b)(10)1910.134(b)(10)Respiratory Protection
“ “Persons should not be assigned to Persons should not be assigned to tasks requiring use of respirators tasks requiring use of respirators unless it has been determined that unless it has been determined that they are physically able to perform the they are physically able to perform the work and use the equipment.”work and use the equipment.”
Conditions which may limit Conditions which may limit respirator userespirator use
any lung disease (e.g., emphysema, any lung disease (e.g., emphysema, COPD, allergies, asthma)COPD, allergies, asthma)
x-ray evidence of pneumoconiosisx-ray evidence of pneumoconiosis reduced pulmonary functionreduced pulmonary function heart diseaseheart disease cerebral blood vessel diseasecerebral blood vessel disease hypertensionhypertension
Respiratory SystemRespiratory System
function:function:• gas exchange between atmosphere & gas exchange between atmosphere &
bloodblood parts:parts:• upper respiratory system:upper respiratory system:–mouth, nose, pharynx, larynxmouth, nose, pharynx, larynx
• lower respiratory system:lower respiratory system:– trachea, bronchi, bronchioles, lungstrachea, bronchi, bronchioles, lungs
The LungsThe Lungs
very large surface area: very large surface area: 145 M145 M22 in healthy male (or, in healthy male (or, about 40 times greater than about 40 times greater than surface area of our external skin)surface area of our external skin)
very thin membrane required at gas very thin membrane required at gas exchange area: exchange area: only 1/2 to 1 micron thick in only 1/2 to 1 micron thick in healthy personshealthy persons
micron? micron?
MicronMicron
one millionth of a meterone millionth of a meter
about 1/ 1000th the size of a hairabout 1/ 1000th the size of a hair
umum
The Nose The Nose
Warms, cools airWarms, cools air Humidifies airHumidifies air Filters particulates Filters particulates > > 10 microns 10 microns
(nose hairs and turbinate (nose hairs and turbinate impaction)impaction)
Reacts with water soluble gasesReacts with water soluble gases Preferred entrance of airPreferred entrance of air
The PharynxThe Pharynx
the chamber which collects the chamber which collects incoming air and foodincoming air and food
passes air to tracheapasses air to trachea regulates air pressure and velocityregulates air pressure and velocity filters particles (2 to 10 microns) filters particles (2 to 10 microns)
through impactionthrough impaction reacts with water soluble gasesreacts with water soluble gases
The TracheaThe Trachea
passage from pharynx to lungs passage from pharynx to lungs the “windpipe”the “windpipe” largest conduit to lungslargest conduit to lungs filters particles 2 to 10 micronsfilters particles 2 to 10 microns very sensitive (cough reflex)very sensitive (cough reflex)
The BronchiThe Bronchi
two subdivisions of the tracheatwo subdivisions of the trachea one for each lungone for each lung further subdivide into segmental further subdivide into segmental
bronchibronchi filters particles 2 to 10 micronsfilters particles 2 to 10 microns
The BronchiolesThe Bronchioles
smaller subdivisions of bronchismaller subdivisions of bronchi lower velocity = settlinglower velocity = settling flow less turbulentflow less turbulent removes particles from 2 to 0.5 removes particles from 2 to 0.5
micronsmicrons smooth muscle layer constrictssmooth muscle layer constricts
The Alveoli (Air Exchange)The Alveoli (Air Exchange)
respiratory bronchioles and respiratory bronchioles and alveolar ductsalveolar ducts
small air sacssmall air sacs covered with capillariescovered with capillaries immunologic protection immunologic protection
(macrophage)(macrophage)
Factors Determining Factors Determining DepositionDeposition
size size densitydensity shape (fiber, aspect ratio)shape (fiber, aspect ratio) solubility (water vs lipid) solubility (water vs lipid) chemical composition (toxic vs chemical composition (toxic vs
inert)inert)
The following slides are not for the class The following slides are not for the class to see, but rather just instructor notesto see, but rather just instructor notes
Types of Pulmonary DiseaseTypes of Pulmonary Disease
ObstructiveObstructive- larger airways: asthma, - larger airways: asthma, bronchitis, COPD, emphysemabronchitis, COPD, emphysema
RestrictiveRestrictive- lung cannot expand fully - lung cannot expand fully or oxygen transfer inhibited: or oxygen transfer inhibited: hypersensitivity pneumonitis, hypersensitivity pneumonitis, asbestosis, silicosis, black lung, asbestosis, silicosis, black lung, berylliosisberylliosis
EmphysemaEmphysema
--occurs when adjacent walls in alveoli --occurs when adjacent walls in alveoli break through, causing a reduction break through, causing a reduction in the number of air sacsin the number of air sacs
--this decreases the total gas exchange --this decreases the total gas exchange surface that is availablesurface that is available
--over time, the lung becomes less --over time, the lung becomes less elastic, and the outflow of air is elastic, and the outflow of air is obstructedobstructed
Chronic bronchitisChronic bronchitis
-- inhaled irritants cause excessive -- inhaled irritants cause excessive production of mucous in lower production of mucous in lower respiratory passagesrespiratory passages
--they also cause inflammation & fibrosis --they also cause inflammation & fibrosis (hardening) of the skin surface (mucosa)(hardening) of the skin surface (mucosa)
--the result: airway obstruction, poor --the result: airway obstruction, poor ventilation of lungs, & interference with ventilation of lungs, & interference with the gas exchange processthe gas exchange process
--also, bacteria thrive in the mucous, & so --also, bacteria thrive in the mucous, & so pulmonary infections often occurpulmonary infections often occur
Types of DefenseTypes of Defense
nose hairs/ turbinatesnose hairs/ turbinates impaction / centrifugal / cyclonicimpaction / centrifugal / cyclonic cough reflex, sneeze reflexcough reflex, sneeze reflex mucus blanket, ciliated cellsmucus blanket, ciliated cells bronchioconstrictionbronchioconstriction settling, Brownian motionsettling, Brownian motion immune responseimmune response
Protective MeasuresProtective Measures
Many of these defense mechanisms Many of these defense mechanisms can deteriorate with age, or be can deteriorate with age, or be compromised as a result of illness, compromised as a result of illness, tobacco smoking, or exposure to tobacco smoking, or exposure to chemical irritants.chemical irritants.
So, choose & control your exposures So, choose & control your exposures wisely!wisely!