autonomic nervous system that carries impulses
to blood vessels. Which blood vessels? Which
tissue in these vessels? Explain why normal
vasoconstriction is important. Explain howgreater vasoconstriction is brought about. Explain
how vasodilation is brought about. How will
each of these changes affect blood pressure?
(pp. 312–313)318 The Vascular System
FOR FURTHER THOUGHT
- Some old textbooks used the term descending aorta.
Explain what is meant by that, and why it is not a
very good term. Explain why an aneurysm of the
aorta is quite likely to rupture sooner or later. - Renee, a nurse, is first on the scene of a car acci-
dent. The driver has been thrown from the car, and
even from 15 feet away, Renee knows that a large
artery in the man’s leg has been severed. How does
she know this? What two things does she see?
Renee stops the bleeding, but the ambulance has
not arrived. She wants to assess the man’s condition
after he has lost so much blood. She cannot take a
blood pressure, but what other vital sign can be
helpful? Explain. If Renee could take a blood pres-
sure reading, what might it be? Might it be within
the normal range? Explain.
3. A friend tells you that her grandmother has a ten-
dency to develop blood clots in the veins of her
legs. Your friend fears that her grandmother will
have a stroke as a result. How would you explain
that a stroke from a clot there is not likely? Because
you are a good friend, you want to explain the seri-
ous result that may occur. How would you do that?
4. Some people with hypertension take prescribed
diuretics. Some call these “water pills.” Is this an
accurate name? How can a diuretic help lower
blood pressure? What disadvantage does the use of
diuretics have?
5. Sinusoids are found in the liver and pituitary gland.
For each of these organs, name four specific large
molecules that enter the blood by way of sinusoids.