# Activity 7

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• Published : October 24, 2012

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Exercise 7: Respiratory System Mechanics: Activity 1: Measuring Respiratory Volumes and Calculating Capacities Lab Report
Pre-lab Quiz Results
You scored 100% by answering 5 out of 5 questions correctly. 1. Which of the following statements describing the mechanics of breathing is false? You correctly answered: d. Ventilation relies exclusively on contracting skeletal muscles. 2. The contraction of which of the following muscles will increase the thoracic cavity volume during inspiration? You correctly answered: c. the external intercostals

3. At the beginning of inspiration, the
You correctly answered: b. thoracic cavity volume increases. 4. At the beginning of expiration, the
You correctly answered: a. pressure in the thoracic cavity increases. 5. A tidal volume refers to the
You correctly answered: b. amount of air inspired and then expired with each breath under resting conditions.

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Experiment Results
Predict Question:
Predict Question: Lung diseases are often classified as obstructive or restrictive. An obstructive disease affects airflow, and a restrictive disease usually reduces volumes and capacities. Although they are not diagnostic, pulmonary function tests such as forced expiratory volume (FEV1) can help a clinician determine the difference between obstructive and restrictive diseases. Specifically, an FEV1 is the forced volume expired in 1 second. In obstructive diseases such as chronic bronchitis and asthma, airway radius is decreased. Thus, FEV1 will Your answer : a. decrease proportionately.

Stop & Think Questions:
Which muscles contract during quiet expiration?
You correctly answered: d. None of these muscles contract during quiet expiration. 6. Minute ventilation is the amount of air that flows into and then out of the lungs in a minute. Minute ventilation (ml/min) = TV (ml/breath) x BPM (breaths/min).

Using the values from the second recorded measurement, enter the minute ventilation in the field below and then click Submit to record your answer in the lab report.
11. A useful way to express FEV1 is as a percentage of the forced vital capacity (FVC). Using the FEV1 and FVC values from the data grid, calculate the FEV1 (%) by dividing the FEV1 volume by the FVC volume (in this case, the VC is equal to the FVC) and multiply by 100%.

Enter the FEV1 (%) for an airway radius of 5.00 mm in the field below and then click Submit to record your answer in the lab report.
12. A useful way to express FEV1 is as a percentage of the forced vital capacity (FVC). Using the FEV1 and FVC values from the data grid, calculate the FEV1 (%) by dividing the FEV1 volume by the FVC volume (in this case, the VC is equal to the FVC) and multiply by 100%.

Enter the FEV1 (%) for an airway radius of 3.00 mm in the field below and then click Submit to record your answer in the lab report.
Experiment Data:
5.00
5.00
4.50
4.00
3.50
3.00

Flow
(L/min)
7485
7500
4920
3075
1800
975

TV

ERV

IRV

RV

VC

FEV1

TLC

Breath Rate

499
500
328
205
120
65

--1200
787
492
288
156

--3091
2028
1266
742
401

--1200
1613
1908
2112
2244

--4791
3143
1962
1150
621

--3541
2303
1422
822
436

--5991
4756
3871
3262
2865

15
15
15
15
15
15

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Post-lab Quiz Results
You scored 100% by answering 5 out of 5 questions correctly. 1. To calculate a person's vital capacity, you need to know the TV, ERV, and You correctly answered: c. IRV.
2. Measuring a person's FVC means that you are measuring
You correctly answered: d. 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. 3. Measuring a person's FEV1 means that you are measuring

You correctly answered: b. the amount of the VC that is...