3 week 13 Flashcards
diff bw internal and external respiration?
- internal: oxidative phosphorylation
- external: exchange of O2 and CO2 bw atmosphere and body tissues
whats the path of airflow through the body?
- air enters nose/mouth and nasal/oral cavity
- pharynx
- larynx
- trachea
- branches to bronchi
- branches to bronchioles
- branches to alveolar sacs
diff bw conducting zone and respiratory zone?
- conducting zone: where air is warmed, humidified, particles removed
- respiratory zone: where gas exchange occurs (respiratory bronchioles + alveolar sacs ONLY)
function of cilia that line the airway?
mucous elevator! (propel mucus containing trapped particles up to glottis and then into pharynx, where mucus is then swallowed)
which cells secrete mucous?
goblet cells
T or F: adjacent alveoli are completely independent structures
false! they are connected by alveolar pores which allow air flow + pressure equilibration
where are type i and ii cells located? what are their functions?
- located in alveoli
- type i cells: very thin, facilitate gas exchange
- type ii cells: secrete surfactant, reduce surface tension
whats the visceral pleura? parietal pleura? intrapleural space/pleural cavity?
- visceral pleura: lines surface of lungs
- parietal pleura: lines wall of chest + diaphragm
- intrapleural space/pleural cavity: fluid filled area between those ^
describe pulmonary circulation. when does blood become oxygenated?
- heart (right ventricle)
- pulmonary trunk
- pulmonary arteries
- pulmonary arterioles
- capillaries (BECOMES OXYGENATED HERE)
- pulmonary venules
- pulmonary veins
- heart (left atrium)
whats boyle’s law?
- “if the volume of a container increases, the pressure falls; if the volume decreases, the pressure rises”
whats Patm, Palv, and Pip?
- Patm (atmospheric pressure) = 760mmHg
- Palv (alveolar pressure) = varies with inspiration/expiration
- Pip (intrapleural pressure) = always less than those ^
where does air move when…
a) Palv = Patm
b) Palv < Patm
c) Palv > Patm
- recall: air moves from high to low pressure
a) no air movement
b) inspiration (+ lung volume)
c) expiration (- lung volume)
how do intra-alveolar pressures and lung volumes change as we breathe?
- at inspiration, Palv drops to 759mmHg (-1)
- at end of inspiration, gas molecules in lungs exert pressure, making inside/outside pressures equal to 760mmHg (0)
- at expiration, pressure increases equal to 761mmHg (+1), causing air to exit lungs
which muscles are involved in breathing?
- inspiration: external intercostals and diaphragm contract
- expiration: quiet breathing = external intercostals and diaphragm relax, forced expiration = internal intercostals and abs contract
why is the intrapleural pressure always negative? what is the purpose of this?
- why: bc opposing forces exerted by chest wall and lungs pull parietal and visceral pleura apart (but they do not separate, think wet microscope slides example)
- purpose: lungs follow chest wall
whats pneumothorax? what are treatments for it?
- pneumothorax: hole in chest wall (i.e., from injury) creates pneumothorax, where air is allowed to enter pleural cavity. pressure in cavity becomes 0 and lung collapses.
- treatments: nothing (heals itself) or remove air with syringe.
airflow = ___ / ___
pressure / resistance
compliance = ___ / ___
volume / pressure
how do elasticity and surface tension influence compliance?
- more elasticity = less compliant
- more surface tension = less compliant
think “compliance = expandable”
what does aging empysema do to lungs?
makes lungs more compliant, meaning air easily gets in, but has a hard time getting out.
what does fibrosis do to the lungs?
makes lungs less compliant, meaning air has a hard time getting in, but easily gets out.
whats the law of laplace?
P = 2T/r
why is surfactant more concentrated in smaller alveoli?
prevents the smaller alveoli from collapsing into the larger alveoli
whats the relationship between airway resistance and alveoli radius
- R = 1/r^4
- A small change in radius (r) causes a large change in resistance (R)
what factors alter airway resistance?
- contractile activity of smooth muscle (bronchoconstriction/PNS/histamine or bronchodilation/SNS/E/+CO2)
- mucus secretion
what are…
a) VT
b) IRV
c) ERV
d) RV
a) tidal volume (~500 ml), vol of air that moves into and out of the lungs during a single, unforced breath.
b) inspiratory reserve volume (~3000 ml), max vol of air that can be inspired from the end of a normal inspiration.
c) expiratory reserve volume (~1000 ml), max vol of air that can be expired from the end of a normal expiration.
d) residual volume (~1200 ml), vol of air remaining in the lungs after a maximum expiration.
what are…
a) VC
b) IC
c) FRC
d) TLC
a) vital capacity = IRV + ERV + VT
b) inspiratory capacity = IRV + VT
c) functional residual capacity = ERV + RV
d) total lung capacity = IRV + ERV + RV + VT (~5700 ml)
what is FEV1?
- how fast you can get air out of the lungs
- normal FEV1 is 80%
- low FVC = restrictive pulmonary disease (low compliance)
- low FEV1 = obstructive pulmonary disease
characteristics of obstructive pulmonary diseases?
- residual volume increases (harder to exhale)
- functional residual capacity increases
- vital capacity decreases
- FEV1 decreases
characteristics of restrictive pulmonary diseases?
- more difficult for lungs to expand
- total lung capacity decreases
- vital capacity decreases
- FEV1 same or increases.
what is minute ventilation?
- total volume of air entering and leaving respiratory system each minute
- VT x resp rate
- normal: 500 mL x 12 breaths/min = 6000 mL/min!
what is dead space?
volume of air in conducting zone that does not participate in gas exchange (~150 mL)
what is alveolar ventilation?
- volume of fresh air reaching the gas exchange areas per minute
- (VT - DSV) x RR
is it more efficient to increase tidal volume than respiratory rate to enhance alveolar ventilation?
yes, when tidal volume is increased, the total increase in volume in excess of the dead space volume adds to the fresh air reaching the alveoli.
