Module 2 The Endocrine System

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Crash Course - The Endocrine System

Introduction

Consider how you feel when you worry about exams, deadlines, sick friends, or a relationship with a girlfriend/boyfriend. Your body responds with a racing heart beat, sweaty hands, fast breathing, and maybe sleeplessness.

In this activity, you will measure one or, if possible, both of the following physiological changes: pulse, which is an indirect measure of heart rate (as you learned in Biology 20) and blood pressure. Measuring blood pressure will be dependant on availability of a blood pressure monitor. When you have completed the lab you will submit the data table, four analysis questions and the conclusion for assessment.

Problem (Purpose) (Optional)

How does a stressful situation affect pulse (and blood pressure)?

Materials

• test questions that you can get from your instructor

• clock/watch with a second hand

• blood pressure monitor (If you do not have a blood pressure monitor at home, you can contact your instructor for options. Many drug stores and pharmacies have blood pressure facilities or equipment available. As well, your local health unit may allow you to use a blood pressure monitor.)

Procedure

1. Work with a partner or a small group. You will be the experimenter and the other members will be the subjects.
2. Using a watch with a second hand, the experimenter will time the subject as he/she sits in a comfortable chair with eyes closed and taking deep, relaxing breaths for 2 minutes.
   
   At the end of the relaxation period, the experimenter will take and record the subject’s pulse, and if possible his/her blood pressure. To review how to take a pulse, you can go to any of your favourite “how to” sites. If you are measuring the pulse manually, you can count the number of pulses in 15 seconds and then multiply by 4 to get the heart rate per minute. In the picture, notice where you place the fingers in order to feel the strongest pulse.
   
   If you are using a digital blood pressure monitor, the instructions are usually included with the machine. Blood pressure monitors are often equipped to measure your pulse as well as your blood pressure. If you are using a blood pressure monitor, you can leave the cuff on the subject for the next step. These values will provide baseline data of your subject in a relaxed state.

3. The experimenter will note the time and administer the test to the subject. The subject will have 2 minutes to complete the test. The experimenter should harass the subject by telling him/her to “hurry” and/or telling him/her that they only have so many seconds left to complete the test.
4. At the end of the 2 minutes, shout “Time is up!” and immediately take and record the subject’s pulse and, if possible, blood pressure, and then again after 2 minutes, and once again two minutes after that. You should have a total of four readings.

Data
Complete the data table

Analysis

Complete the questions in the online assignment

Conclusion

In this lab, both the nervous and endocrine systems brought about the physiological changes that you measured. What conclusion can you make from this lab as to how a stressful situation affects pulse and blood pressure? Which parts of the nervous and endocrine systems were involved? What can you conclude about the body’s ability to recover from stressful situations? How were the nervous and endocrine systems involved in this recovery? Write a response to these questions in the Assignment document.