PhysioEx Ex. 7 Act. 1: Measuring respiratory volumes and calculating capacities

ventilation

breathing; two phases

1. inspiration

2. expiration

inspiration

air taken into the lungs, occurs as external intercostal muscles and diaphragm contract

expiration

air expelled from lungs

diaphragm

dome shaped muscle; flattens as it moves inferiorly while external intercostals lift ribcage

• rises during expiration

external intercostals

cause inspiration, lift ribcage

internal intercostals

contract during expiration to force additional air from lungs (ex. coughing, sneezing, blowing up a balloon)

ERV

expiratory reserve volume

• amount of air that can be forcefully expired after a normal tidal volume expiration

• male: 1200 ml

• female: 700 ml

FVC

forced vital capacity

• amount of air that can be expelled when the subject takes the deepest possible inspiration and forcefully expires as completely and rapidly as possible

TV

tidal volume

• amount of air inspired and then expired with each breath under reasting condtions (500 ml)

IRV

inspiratory reserve volume (IRV)

• amount of air that can be forcefully inspired after a normal tidal volume inspiration

• male: 3100 ml

• female: 1900 ml

RV

residual volume

• amount of air remaining in the lungs after forceful and complete expiration

• males: 1200 ml

• female: 1100 ml

FEV

forced expiratory volume

• measures the amount of the vital capacity that is expired during the first second of the FVC test (normally 75-85% of the vital capacity)

which of the following statements describing the mechanics of breathing is false?

1. ventilation refers to the movement of air into and out of the lungs

2. ventilation is measured as the frequency of breathing multiplied by the tidal volume

3. ventilation includes the processes of inspiration and expiration

4. ventilation relies exclusively on contracting skeletal muscles

4. ventilation relies exclusively on contracting skeletal muscles

the contraction of which of the following muscles will increase thoracic cavity volume during inspiration?

1. the abdominal wall muscles

2. the internal intercostals

3. the external intercostals

4. the intercoastal highways

3. the external intercostals

at the beginning of inspiration, the

1. diaphragm relaxes

2. thoracic cavity volume increases

3. diaphragm becomes dome shaped

4. thoracic cavity pressure increases

4. thoracic cavity pressure increases

at the beginning of expiration, the

1. pressure in the thoracic cavity increases

2. abdominal muscles relax

3. volume of the thoracic cavity increases

4. external intercostal muscles contract

1. pressure in the thoracic cavity increases

a tidal volume refers to the

1. maximum amount of air that can be forcefully inspired

2. amount of air inspired and then expired with each breath under resting condtions

3. the maximum amount of air that can be forcefully expired

4. the twice daily changes in breathing that are influenced by the moons gravitational pull

2. amount of air inspired and then expired with each breath under resting condtions

which muscles contract during quiet expiration?

1. external intercostal muscles and the diaphragm

2. abdominal-wall muscles and internal intercostal muscles

3. external and internal intercostal muscles

4. none of these muscles contract during quiet expiration

4. none of these muscles contract during quiet expiration

how is minute ventilation calculated

the amount of air that flows into and then out of the lungs in a minute

MV (ml/min) = TV (ml/breath) x BPM (breaths/min)

how is FEV % calculated

FEV/FVC or VC x 100

to calculate a persons vital capacity, you need to know the TV, ERV, and

1. RV

2. FEV

3. IRV

4. TLC

3. IRV

measuring a persons FVC means that you are measuring

1. the amount of air remaining in the lungs after a forceful and complete expiration

2. the sum of VC and RV

3. the amount of the VC that is expired during 1 second

4. the amount of air that can be expelled when the subject takes the deepest possible inspiration and then forcefully expires as completely and rapidly as possible

4. the amount of air that can be expelled when the subject takes the deepest possible inspiration and then forcefully expires as completely and rapidly as possible

measuring a persons FEV means that you are measuring

1. the sum of the VC and the RV

2. the ammount of the VC that is expired during the first second of the FVC test

3. the amount of air trapped in the lungs after a forceful and complete expiration

4. the amount of air that can be expelled when the subject takes the deepest possible inhalation and forcefully expires as completely and rapidly as possible

2. the ammount of the VC that is expired during the first second of the FVC test

for a person suffering an asthma attack, inhaler medications are expected to

1. reduce the airway resistence

2. reduce the FEV

3. reduce the airway radius

4. reduce the TLC

1. reduce the airway resistence

which of the following values does not include the ERV

1. FVC

2. TLC

3. TV

3. TV

lung diseases are often classified as

obstructive or restrictive

obstructive diease

affects airflow

• ex bronchitis and asthma

• airway radius is decreased

restrictive disease

reduces volume and capacities

what would be an example of an everyday respiratory even the ERV stimulates

forced expiration

• coughing

• sneezing

• blowing out candles or balloon

• laughing

what additional skeletal muscles are utilized in an ERV activity

internal intercostal muscles and abdominal wall muscles

what happened to the FEV as the radius of the airways decreased?

• When the airway radius drops, the volume of air that can be forcefully blown out in the first second decreases.

• Increased Resistance: Narrower airways increase resistance to airflow significantly (following Poiseuille's law, where flow rate drops sharply as radius decreases).

• Obstructive Pattern: This proportional decline in FEV1 with a reduced airway radius mimics obstructive pulmonary conditions (like asthma or chronic bronchitis) rather than restrictive disease

explain why the results from the experiment suggest that there is an obstructive rather than a restrictive pulmonary problem

The results suggest an obstructive pulmonary problem because the reduction in airway radius caused a sharp decline in both FEV₁ and the FEV₁% ratio, while a restrictive problem would keep the ratio normal or elevated.

• Obstructive pattern: Narrowed airways block airflow, causing FEV₁ and the FEV₁% ratio to drop sharply because air cannot quickly escape. This matches the lab results.

• Restrictive contrast: Restrictive problems involve stiff lungs with clear airways, meaning total volume drops but the FEV₁% ratio stays normal or high because air leaves without resistance.