Heart Action and EKG Rhythm Strips
Name ____________________________________________ Period ________
I. ___________________ carries oxygenated
blood to the body. Baroreceptors here detect
changes in blood pressure and in response to
stretching will decrease heart rate.
A. ___________________
initiates the cardiac cycle
by generating a nervous
impulse (the pacemaker of
the heart).
H. ___________________
carries deoxygenated
blood to the lungs.
G. ___________________
receives oxygenated blood
from the lungs.
B. ________________
delays the impulse
allowing atrial
contraction to finish.
F. ___________________
specialized conducting
fibers that transmit
impulses through
ventricles making them
contract together.
C.___________________
distributes nerve impulse
over the ventricles causing
contraction.
D. _________________
pumps oxygenated blood
to the lungs.
E. ___________________
pumps blood from the left
atrium to the aorta.
Identify the common rhythms. Choose from:
normal sinus rhythm
sinus bradycardia
ventricular tachycardia
ventricular fibrillation
preventricular contraction (PVC)
1._______________________________________
2. _______________________________________
3. __________________________________________
atrial fibrillation
sinus tachycardia
4. _____________________________________________
5. ____________________________________________
6. ______________________________________________
7. __________________________________________________
8. Let’s measure the heart rates for #2, 4, and 7. Each strip is 6 seconds long.
#2 ______________beats per minute
#3 ______________bpm
#7 ______________bpm
9. Identifying the waves. On strip #7, identify and label the P wave, QRS complex, and the T wave.
10. Which wave represents atrial contraction? ________________________________
11. Which wave represents ventricular contraction? ___________________________________
12. Which wave represents ventricular repolarization (relaxation)? __________________________________
A.
B.
C.
13. Of the images above which one represents the P wave? _________
Which represents the QRS complex? __________
Which represents the T wave? __________
Athletes and the Heart
Total Heart Volume of
Athletes and Non-Athletes
Heart Volume
Relative to Body
Weight
1000
800
600
400
200
0
body builders
endurance
athletes
average person
Athletic Training
Reativel Heart Volume (cm3 per kg)
Total heart volume (cm3)
1200
18
16
14
12
10
8
6
4
2
0
body builders
(avg 90 kg)
endurance
athletes
(avg=69kg)
Type of athlete
1. Explain why heart size increases with endurance activity:
2. Look at the graphs above. Explain why the relative heart volume of endurance athletes is greater than that
of body builders even though their total heart volumes are the same:
3. Heart stroke volume increases with endurance training. Explain what stroke volume is and how it increases
the efficiency of the heart as a pump:
4. The resting pulse is much lower in trained athletes compared with non-active people. Explain the health
benefits of a lower resting pulse: