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Figure 13. The contraction of the heart and the action of the nerve nodes located on the heart. Images from Purves et al., Life: The Science of Biology , 4th Edition, by Sinauer Associates ( www.sinauer.com ) and WH Freeman ( www.whfreeman.com ), (please get permission)

Electrical activity

  • The electrical activity in the heart is so strong that is can be measured from the surface of the body as an electrocardiaogram (ECG).
  • A normal heart has a very regular rhythm.
  • An abnormal heart may have an arrhythmia, or abnormal rhythm as shown in the figures.
Figure 15. Normal cardiac pattern (top) and some abnormal patterns (bottom). Images from Purves et al., Life: The Science of Biology , 4th Edition, by Sinauer Associates ( www.sinauer.com ) and WH Freeman ( www.whfreeman.com ), (please contact for permission).

Investigation: Heart Health and Measuring Heart rate

Part 1: Investigating your cardiovascular fitness

Aim :To investigate your heart rate before, during and after strenuous aerobic exercise.

Method :

  1. Work in pairs on the field and ensure you have a stop watch.
  2. One partner performs the experiment and the other records the results. Partners then swap roles.
  3. Take the resting pulse rate before exercising.
  4. One partner runs quickly around the field twice.
  5. Immediately after the run take his pulse.
  6. Continue to take his pulse every minute for 5 minutes.
  7. Record the results and plot a graph using the data pertaining to you.

Results : Record results in a table like the one indicated below

Before exercise (resting)
0 min (immediately after exercise)
1 min (after exercise)
2 min
3 min
4 min
5 min

Draw a line graph to illustrate your results on the following axis (show the resting pulse rate as a separate dotted line on the axis).

Mark allocation: heading x-axis scale x-axis label 

y-axis scale y-axis label plotting graph 

neat and done in pencil 


1.Write a hypothesis for this investigation.

2.Write down the independent variable.

3.Write down the dependent variable.

4.Name ONE factor that must be kept constant during this investigation.

5.Write down TWO ways in which the accuracy of this investigation can be


6.What conclusions can be made about your cardiovascular fitness?

7.Explain why the heart rate increases during exercise?

Part 2: Investigating your family’s heart health:


  1. Draw up a table to record the answers to the following yes/no questions:

i. Do you smoke?

ii. Are you overweight?

iii. Do you exercise regularly?

iv. Do you follow a healthy diet (low fat, low salt)

v. Do you have your blood pressure checked regularly?

vi. Do you have a family history of heart and circulatory disease?

  1. Survey two adult male family member (father, grandfather or uncle) and two adult female family members (mother, grandmother or aunt). Include the adults’first name, gender, age and relationship to you.

3.Record the results in your table. Also indicated the score they obtained:

i. yes=0; no=5

ii. yes=0; no=5

iii. yes=5; no=0

iv. yes=5; no=0

v. yes=5; no=0

vii. yes=0; no=5

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
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Devang Reply
are you nano engineer ?
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Abhijith Reply
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s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
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s. Reply
of graphene you mean?
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in general
Graphene has a hexagonal structure
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Sanket Reply
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Damian Reply
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abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
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I'm interested in nanotube
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Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
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I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
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Source:  OpenStax, Siyavula: life sciences grade 10. OpenStax CNX. Apr 11, 2012 Download for free at http://cnx.org/content/col11410/1.3
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