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75 Cards in this Set
- Front
- Back
What is the primary function of the respiratory system? |
gas exchange between air and circulating blood |
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What is the secondary function of the respiratory system? |
acid-case balance (by regulating CO₂ in the blood) |
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The respiratory system consists of ___ and ___ zones |
conducting and respiratory zones |
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conducting zone |
from nasal cavity to terminal bronchioles "dead space" |
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respiratory zone |
respiratory bronchioles and alveoli |
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respiratory muscles |
diaphragm and other muscle that promote ventilation |
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ANS regulates smooth muscle to control _____ diameter |
ANS regulates smooth muscle to control bronchiole diameter |
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bronchodilation |
controlled by SNS → reduces resistance |
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bronchoconstriction |
controlled by PNS and histamine release (allergies) → increases resistance |
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What is alveoli? |
air-filled pockets within lungs where gas exchange takes place |
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Alveoli are patrolled by _____ _____ (dust cells) - phagocytize microbes |
alveolar macrophages |
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What are Type 1 cells? |
thin, delicate endothelial cells |
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What are Type 2 cells? |
produce surfactant (oily secretion - coats epithelium & reduce surface tension) |
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Surface tension |
caused by attraction of H₂O molecules to each other (collapses alveoli) (premature babies - immature Type 2 cells = little/no surfactant) |
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Pulmonary capillaries |
exchange CO₂ and O₂ with alveoli |
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Respiratory Membrane |
thin membrane of alveoli where gas exchange takes place (air-blood interface) |
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What are the three layers that gases must diffuse across? |
1. Type 1 alveolar cells |
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Blood supply to the lungs: pulmonary circuit |
purpose is gas exchange (also nourishes respiratory membrane) |
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Blood supply to the lungs: systemic circuit |
purpose is to nourish lung tissue |
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Each lung is located within a double-layers _____ membrane |
serous |
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Visceral pleura |
lines outer lung surface |
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Parietal pleura |
lines inner surface of thoracic wall |
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Thoracic wall: |
• floor - diaphragm |
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The right and left pleural cavities are separated by the _____ |
mediastinum |
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Each pleural cavity holds a long and lungs function ____ |
independently |
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pleural cavity |
holds serous fluid that reduces friction as lungs inflate/deflate |
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What are the two principles affecting air movement? |
atmospheric pressure and Boyle's Law |
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Atmospheric Pressure |
(Patm) ~ weight of the Earth's atmosphere (on our bodies and everything around us) |
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Respiratory Pressure |
is describe relative to Patm |
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Boyle's Law |
defines the relationship between gas pressure and volume |
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Respiratory cycle |
1 inspiration (inhalation) + 1 expiration (exhalation) |
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Mechanics of Breathing |
based on pressure differences (△P) between air in lungs and atmosphere during on Respiratory Cycle |
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What is the normal atmosphere pressure? |
1 atm at sea level = 760 mm Hg |
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intra-alveolar pressure (Palv) |
pressure of the lungs (within alveoli) |
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During relaxed breathing .... |
inhalation = −1 mm Hg inside lungs |
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At rest ("Quiet" inspiration/expiration) the most important muscles are: |
diaphragm and external intracostal muscles of the ribs |
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accessory respiratory muscles → |
activated only when respiration increases significantly ("forced" inspiration/exhalation) |
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Quiet inspiration |
diaphragm and external intercostal muscles (inspiratory muscles) contract and the rib cages rises |
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Quiet expiration |
inspiratory muscles relax and the rib cage descends due to gravity |
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What are some physical properties of the lungs? |
elasticity, compliance, and airway resistance |
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What is elasticity? |
stretching force |
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What is compliance? |
ease of expansion |
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What is airway resistance? |
depends of diameter of lungs |
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Respiratory system adapts to changing oxygen demands by varying: |
• number of breaths per minute (respiratory rate) ( |
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respiratory rate |
number of breaths per minute |
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tidal volume |
volume of air moved per breath (Vt) |
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Respiratory Minute Volume |
(VE) - amount of air moved per minute calculated by: |
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Anatomical Dead Space |
volume of air that doesn't reach alveoli (air remaining in conducting passages - trachea, mouth, etc) |
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Alveolar Dead Space |
if alveoli cease in gas exchange (e.g. damage or lined with mucus) |
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Total Dead Space |
(Vd) = Anatomical Dead Space + Alveolar Dead Space |
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Alveolar Ventilation (VA) |
amount of air reaching alveoli each minute |
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Measurements of airflow: Respiratory volumes |
TV = volume of one breath |
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Measurements of airflow: Respiratory volumes |
IRV = volume inhaled with maximum effort in excess of tidal volume |
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Measurements of airflow: Respiratory volumes |
ERV = volume exhaled with max. effort in excess of tidal volume |
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Measurements of airflow: Respiratory volumes |
RV = volume remaining in lungs after max. expiration (keeps alveoli inflated) |
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Measurements of airflow: Respiratory capacities |
VC = volume exhaled with maximum effort after maximum inspiration |
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Measurements of airflow: Respiratory capacities |
IC = volume of air inhaled after normal tidal expiration |
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Functional residual capacity |
Functional residual capacity = volume in lungs after normal tidal expiration |
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Total lung capacity |
Total lung capacity = maximum volume lungs can contain |
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VC = |
ERV + TV + IRV |
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IC = |
TV + IRV |
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Functional residual capacity = |
ERV + RV |
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Total lung capacity = |
VC + RV |
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Pulmonary function tests |
used to asses one's respiratory status (compared with "normal" values) |
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spirometer |
instrument used to measure different volumes of breathed air (water is displaced by the breathed air, and the volume can be recorded) |
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Obstructive disorder |
difficult to get air out of the lungs (expiration) |
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Restrictive disorder |
difficult to get air into the lungs (inhalation) |
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Gas exchange occurs between air in ____ & ____ |
alveoli & blood → across respiratory membrane |
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Gases are exchange by diffusion in response to a ____ ____ |
concentration gradient |
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To understand how gases are exchanged between air in alveoli & blood you will need to consider: |
1. Partial pressure of gases (Dalton's Law) |
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Dalton's Law of Partial Pressure (PP) |
• Total pressure (of gas mixture) = sum of individual gas pressures... called the partial pressures |
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If you have a container with 4 gases: |
CO₂ = 400 mm Hg |
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Henry's Law of Dissolves Gases |
• When the mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its partial pressure |
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Forced Exhalation includes respiratory accessory muscles such as: |
internal intercostals and abdominal muscles |
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Force Inhalation includes accessory accessory respiratory muscles such as: |
Sternocleidomastoid & scalenes and Pectoralis minor and serratus anterior |