Confine your report solely to the points specified below, paying close attention to the length limits. Marks are also given against each question (total marks 80). For some questions, you will need to consult textbooks or other reference sources. The report should be handed in, at the Undergraduate Office (TM1-85), within ONE week of the date on which the practical is done. The report must represent your own work, and must not be written collaboratively. You must also not copy material from the internet, textbooks or elsewhere. An electronic version of this form is available on Weblearn.
NAMEID NUMBERGROUPDATE OF PRACTICAL
1. Spirometry
(i) Recording of height and age
The following formulae predict, approximately, two specific lung volumes
FORCED VITAL CAPACITY (FVC). This is defined as the maximum volume of gas that can be expelled from the lungs by forceful effort, following a maximal inspiration.
FVC (L) 0.064Hheight - 0.031Hage - 5.33 (MEN)
0.052Hheight - 0.018Hage - 4.36 (WOMEN)
In both these and the subsequent formulae, height must be expressed in cm, and age in years.
TOTAL LUNG CAPACITY (TLC). This is the total amount of gas contained in the lung at the end of a maximal inspiration.
TLC (L) 0.094Hheight - 0.015Hage - 9.17 (MEN)
0.079Hheight - 0.008Hage - 7.49 (WOMEN)
Questions
Give the gender, age and height of your subject. Calculate FVC and TLC for your subject using the above formulae, remembering to include units. Show your calculations (6 lines maximum 5 marks).
Female, age19, hight1,59cm.FVC (0.052)(159cm)-(0.018)(19)-4.36 8.27cm-0.342-4.36 3.57 LTLC (0.079159)-(0.00819)-7.49 12.56 0.152 7.49 4.77 L
The formulae use data for age and height. Why, in terms of physiology, do you think these two variables may be used to predict lung volume (5 lines maximum 5 marks)
In term of physiology, these two variables are used to predict lung volume because age and height are relatively constant, meaning as we age or get taller the numbers are relatively small than they were a year ago. In addition, as we age our lungs become less elastic therefore we have less capacity in our lungs to inhale and exhale air. As for the height factor, the bigger someone is the more lung capacity they have and vice versa when it comes to a person smaller in stature.
Why is FVC always less than TLC Why is this physiologically essential (Hint your answer should refer to the Residual Volume) (5 lines maximum 5 marks)
FVC is always less the TLC because when a person forcibly exhales say during exercise, the left over air in the lungs is the residual volume. The residual volume is essential because the remaining air in our lungs are used to oxygenate the rest of our body. Without our air reserves the body will be depleted of oxygen, which in turn destroy tissues in our muscles and brain.
(ii) Microspirometers
Complete the following Table with the data obtained in the practical. (5 marks)
UnitsBreath 1Breath 2Breath 3AverageFEV1L3.263.173.233.22 LFVCL3.543.453.543.51 LFER0.920.910.91PEFL441445435440 Ls
Why is FER is always less than 100 in healthy subjects Giving the references you used at the end of this report, state what range of FER values is considered normal. (5 lines maximum 5 marks)
FER is always less than 100 in healthy persons because a healthy person often exerts greater force on their lungs to provide their muscles with oxygen. The normal range for FER are values is between 75-80.
Why is FER often used, in preference to FEV1 or PEF, when comparing different subjects (5 lines maximum 5 marks)
FER is often preferred than FEV1 or PEF because FER has a wider, more consistent range and its also a better indication of airflow limitation. Whereas, with the other two, numbers could be askew depending on the force exerted by the subject when breathing during the test.
Compare the estimates of FVC you made by (i) calculation from height and age (ii) using the microspirometer. Suggest possible causes for any differences found. (5 lines maximum 5 marks)
The calculation for the FVC from the formula and microspirometer werent that much different. Some possible causes could have been the amount of air being exhaled into the device. In addition, the force with which the air was being blown could have skewed the numbers a little bit. In addition, with microspirometercalculation individuals must take into account outside forces such as room air and any slight movements made by the individual during testing.
Recalculate your average PEF as L s-1. Is this figure different from that for FEV1 One would normally expect PEF (expressed as L s-1) to be higher than FEV1 - why (5 lines maximum 5 marks)
2. Collection and analysis of expired air
Complete the Table provided below, as indicated. Take note of the units specified for each calculation.
ROWS 1-3. Enter your recorded data here
ROW 4. Minute Volume is the volume of air exhaled per minute. Calculate using the data in row 1.
ROW 5. Tidal Volume is the average volume of each breath. Calculate using data already entered.
ROW 6. Calculate the rate of expiration of oxygen using the data in rows 3 and 4.
ROW 7. Calculate assuming that (i) the concentration of oxygen in room air is 20.9 and (ii) the minute volume of air inhaled is equal to the minute volume exhaled.
ROW 8. Calculate using the data in rows 6 and 7.
ROW 9. Calculate by multiplying the data in row 8 with the correction factor supplied
ROW 10. Calculate using the fact that oxygen consumption (expressed under STPD conditions) is proportional to energy expenditure 1 L of oxygen consumed is approximately equivalent to an energy expenditure of 20 KJ. (10 marks)
RowVariableFigure1Total volume of expired air (L)15.12Number of breaths in one minute (ventilation rate)143Oxygen concentration in expired air () 17.64Exhaled minute volume ATPS (L min-1)0.252 L5Tidal volume ATPS (L)1.09 L 6Oxygen exhalation rate ATPS (ml min-1)14.3 mLmin 7Oxygen inhalation rate ATPS (ml min-1)12.1 mLmin 8Oxygen consumption ATPS (ml min-1) 1.18 mLmin9Oxygen consumption STPD (ml min-1) 10Energy expenditure (J min-1)NOTE In the above table, volume data has been expressed using the terms ATPS and STPD. ATPS means the gas volume measured under actual laboratory conditions of temperature, pressure and humidity these may vary from day to day. STPD conditions on the other hand are standardised, and it is necessary to convert ATPS volumes to STPD before carrying out the calculation for energy expenditure in the above table.
How does your value for resting energy expenditure compare with normal values By how much might energy expenditure increase under conditions of maximum exercise. Give references for your sources, at the end of this report. (5 lines maximum 5 marks)
The range for normal REE values start from 1512J-3112J. Energy expenditure increases greatly when a Person exercises at maximum capacity. The amount it takes to inhale and exhale one breath takes enough Energy imagine how much energy it takes for a person to get through a gruelling workout.
In order to calculate energy expenditure, we assumed that oxygen consumption is proportional to energy expenditure. Explain why this is normally true, and identify when, in a healthy individual, it might not be correct. (5 lines maximum 5 marks)
Normally the amount of oxygen a person consumes is the same amount of energy heshe expends because Breathing normally requires so little energy that the energy used is the same. On the hand, a healthy individualMay expend less energy when breathing because the body has become accustomed to receiving less oxygen Therefore when a healthy person breathes the pressure the exert is far less than that of say an overweight Person because their bodies have more oxygen reserve because they dont breathe in and out as much.
Assuming that each g of ATP used in the body requires 60J to synthesise, how much ATP is your subject using (a) each minute during the measurement (b) each day, assuming that average energy expenditure remains the same as that which you measured Show your calculations and comment on the figures obtained in relation to the synthesis and breakdown of ATP. (10 lines maximum 5 marks)
A. 14 breathsmin 60 secs. 840J B. 14 breaths min 60 min. 16 hrs. 13, 440 J The synthesis and breaking down of ATP requires a lot of energy and these figures are staggering considering This how much energy we need each day just to keep breathing.
The assumption used to complete Row 7 of the Table (that minute volume of inhaled air minute volume of exhaled air) is not quite correct. Three factors contribute to this what are they (7 lines maximum 10 marks)
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