Respiration 37 & 38

The sum of expiratory reserve volume and residual volume

is the volume in the lungs after a tidal volume is expired... cannot be measured by spirometrey

FRC= RV+ERV

is the sum of all four lung volumes

TLC= RV+ERV+VT+IRV

is the sum of the tidal volume, inspiratory reserve volume, and expiratory reserve volume

the volume that is expired after max. inspiration

VC= Vt+IRV+ERV

it is the volume of air that is exhaled during the 1st second of a forced vital capacity manuver...

use FEV1/FVC is 80%... percentage is reduced in obstructive pulmonary disease

Can make: Vt, ERV, VC, FVC, FEV1, and IRV which = Vc- Vt- ERV

Can not make: RV, FRC, and TLC

total volume of air expired per min.

VE' = Vt x Rf

VE' = 500ml/breath x 12 breaths/ min = 6L/min

is the volume form the conducting zone, this is still O2 rich air

typical Vd = 150 ml

Is the alveolar air that is expired per minuite.

alveolar air expired in one breath = (Vt-Vd)

Va' = ( (Vt- Vd) x Rf)

typical : Va' = (500ml - 150ml)/ breath x 12 breaths/ min = 4.2 L/min

Inspired air is measuresd under ATPD conditions - Ambient temperature and pressure, dry

Expired volumes are measured in BTPS- Body temp and pressure, saturated

Increase the temp

Increase the number of molecules n

Decrease the volume

Flow = Drving force/ resistance

Airflow = (Patm- Palveoli) / Airway resistance

We c/n change P atm, so to inspie we decreasee Pa

-Inspiratory muscels contract, chest wall expands and diaphram lowers

- Pip becomes more negative than -5, causing intraplural pressure to increase Ptp

causes the lungs to expand

Have to make Palveoli greater than Patm

Insp. muscles relax, chest wall moves inward, diaphram rises, Pip becomes less negative, Ptp decreases, lung size decrease, Palv increase.... exhale

The transpulmonary pressure does, which is the inside minus the outside.... thus PTP= Pa- Pip

Intraplural pressure must be subatmospheric in order to keep the lungs distended

Abn. low lung compliance

Lungs become stiff, needs abnormally larger distending pressure (Ptp). to make normal FRC, must make Pip more negative than normal

reqires hard work from inspiratory muscles... big decrease in total lung capacity

Compliance= stress/ strain =  A Volume/ A distending pressure

Lung compliance = change in Lung Volume / change in Ptp

Abnormally high airway  resistance

To inspire a normal Vt, must make Pa more negative than during inspiration

To expire a normal Vt, must make Pa more positive than normal during expiration

Mucus in airway - Bronchitis

Swollen or hypertrophic mucosa - Chronic Broncitis, pulmonary edema

SM contraction - bronchospasm, asthma

Floppy airways inside thorax get narrowed during expiration, esp during forced expiration

FEV1/FVC is reduced.... the forced vital capacity is reduced because the TLC is reduced, but the RV is reduced even more

- less alveolar surface area - slowed gas exchange

-Fewer, weaker alveolar walls- Lungs very compliant

-Alveolar springs weak - broncial airways tend to collapse- become obstruced

- Airway collapse leads to air trapping in alveoli - increase RV