pulmonary function last lab!!

Alveoli

• Site of gas exchange

• Thin wall

• Simple squamous epithelium

Spirometry

a technique used to measure lung volumes, calculate lung capacities, and measure rates of air flow

Tidal Volume

(VT) – volume of air that moves into and out of lungs during a single, regular, unforced breath

Inspiratory Reserve Volume

(IRV) – max

volume of air that can be inspired from

end of normal inspiration

Expiratory Reserve Volume

ERV – max volume of air that can be expired from end of normal expiration

Residual Volume

(RV) – volume of air left in the lungs following max expiration

lung volumes

Lung Capacities (sums of two or more lung volumes)

Obstructive Pulmonary Diseases

Involve increases in lung resistance…obstructing the airway

– Asthma, COPD, Bronchitis, Emphysema

Restrictive Pulmonary Disorders :

decreases in lung (airway) compliance…increased lung recoil

Fibrotic types of diseases ‘Stiff Lung’

– Decreased TLC (Total Lung Capacity)

– How easily do the lungs expand?

In addition to measuring resting volumes to

identify pathologies, you can test

rates of air flow

Forced Vital Capacity (FVC) Test

– Max inspiration followed by forced max expiration

Max expiration

Force Expiratory Volume (FEV) Test (FEV1 Test)

Measure of the % FVC that can be exhaled in a certain amount of time (usually 1 second)

Expiration in 1st sec

FEV1 / FVC ratio

FEV1 / FVC ≈ 0.8±0.05 (~80% ± 5%) → Normal ratio

FVC = 3.8 L

FEV1 = 3.1 L

FEV1/FVC = 0.815 (81.5%)

Normal is ~80%...

Does this subject likely have a restrictive,

obstructive or no pulmonary disease? So, this individual is healthy

FVC in patient with:

– Obstructive pulmonary disease?

– Restrictive pulmonary disease?

Obstructive pulmonary disease - low

Restrictive pulmonary disease - low

FEV1 in patient with:

– Obstructive pulmonary disease?

– Restrictive pulmonary disease?

Obstructive pulmonary disease - very low

Restrictive pulmonary disease - normal

Obstructive

– Low FVC

– Very low FEV1

– Very low FEV1/FVC

Restrictive

– Low FVC

– Relatively normal FEV1

– Very high FEV1/FVC

Minute Ventilation

(VE) – total amount of air that flows into or out of the respiratory system in a minute

Respiratory Rate (RR)

– number of breaths per minute

– A.K.A: breathing frequency ( f )

– Average RR = 12 breaths/min

What MUST happen to Minute Ventilation (VE) during exercise?

Increases.

Not all air reaches the respiratory zone

VT = 500 mL…only about 350 mL reaches the alveoli

Dead Space Volume

(DSV) – volume of the

conducting zone

– A.K.A: anatomical dead space

Alveolar Ventilation (VA)

– volume of air reaching the

alveoli each minute

VA : Amount of air that

participates in gas exchange

– VA = (VT x RR) – (DSV x RR)

– VA = (500 mL/breath x 12 breaths/min)

– (150 mL/breath x 12 breaths/min) = 4200 mL/min

Alveolar ventilation is MOST important b/c

that’s what actually participates in gas exchange

Chemoreceptors (blood vessels and medulla)

Decreased pH = increased ventilation

– Increased CO2 = increased ventilation

– Decreased O2 = increased ventilation

Muscle and joint receptors

– Increased mech. stress = increased ventilation

Pain and temperature receptors

Increased pain/temp = increased ventilation

Amount of muscle recruited matters

– Higher intensity exercise:

• Greater muscle mass used

• Greater O2 demand

Aerobic fitness level matters

– Endurance trained individuals:

• Muscles are more efficient

• Less O2 demand for any given workload

Which do you think produces greater changes in

ventilation: upper or lower body exercise?

Lower body