- Calculate cardiac output if stroke volume is 75
mL and pulse is 75 bpm. Using the cardiac output
you just calculated as a resting normal, what is the
stroke volume of a marathoner whose resting
pulse is 40 bpm? (p. 283) - Name the two cardiac centers and state their loca-
tion. Sympathetic impulses to the heart have what
effect? Parasympathetic impulses to the heart
have what effect? Name the parasympathetic
nerves to the heart. (p. 284)- State the locations of arterial pressoreceptors and
chemoreceptors, what they detect, and their sen-
sory nerves. (p. 284) - Describe the reflex arc to increase heart rate and
force when blood pressure to the brain decreases.
(p. 285)
The Heart 289FOR FURTHER THOUGHT
- Endocarditis may be caused by bacteria or fungi
that erode, or wear away, the heart valves, or in
some cases make the valves bumpy (these bumps
are called vegetations—think cauliflower). Explain
the possible consequences of this. - Bob, a college freshman, is telling his new friends
that he has been running seriously for 6 years,
and can run a marathon in a little over 3 hours. His
friends aren’t sure they should believe him, but
don’t want to spend 3 hours waiting while Bob
runs 26 miles. Bob says that he can prove he is
telling the truth in 1 minute. Can he? Explain why
or why not.
3. A neighbor, Mrs. G., age 62, tells you that she
“doesn’t feel right” and is suddenly tired for no
apparent reason. She denies having chest pain,
though she admits to a “full” feeling she calls indi-
gestion. You suspect that she may be having a heart
attack. What question can you ask to help you be
more sure? Explain the physiological basis for your
question.
4. Several types of artificial hearts are being devel-
oped and tested. What are the three essential
characteristics a truly useful artificial heart must
have? One is obvious, the others, perhaps not as
much so.