Pts 1 dif m ref 332 key understanding 59 ans g for

PTS: 1 DIF: M REF: 332 KEY: UNDERSTANDING
59. ANS: G
For circulation to occur, the pressure gradient must be high enough to overcome peripheral resistance and
gravity. The diastolic pressure is the pressure in major arteries when the heart is at rest and is not a direct
factor in blood circulation. Capillary pressure is the pressure within capillaries and is part of the pressure
gradient itself, so it does not need to be “overcome.” The force of gravity must be overcome for blood in the
venous system to flow against it on its way back to the heart. However, bear in mind that the venous system
gets help from the skeletal muscle and respiratory pumps, as well as from valves in veins that stop blood from
flowing backward from the pull of gravity.
PTS: 1 DIF: D REF: 331 | 337 KEY: ANALYZING
60. ANS: D
Blood pressure decreases as distance from the heart increases; therefore, pressure in the arterioles will be
lower than pressure in the larger arteries. An arteriole pressure of 70 mm Hg is normal. Blood vessel diameter
has a critical effect on blood pressure; however, the narrower the vessel, the greater the blood pressure.
PTS: 1 DIF: M REF: 330 KEY: UNDERSTANDING
61. ANS: A
Peripheral resistance is the force that must be overcome for blood to reach the tissues; therefore, the lower the
peripheral resistance, the lower the blood pressure. Resistance is a necessary feature of the circulatory system
—without it, the system would collapse—but in healthy individuals, peripheral resistance is adjusted to keep
blood pressure normal.
PTS: 1 DIF: M REF: 331 KEY: APPLYING
62. ANS: C
Vasodilation decreases resistance; the less the resistance, the less pressure required to overcome it. Blood
pressure increases with cardiac output. Vasodilation does not increase venous return. Vasodilation increases
velocity (flow).
PTS: 1 DIF: M REF: 332 KEY: ANALYZING
63. ANS: A
The medulla coordinates blood pressure control. The brainstem contains the medulla, but it has many other
structures and function as well. Baroreceptors have a role in short-term blood pressure control but are located
in the carotid arteries and the aortic arch, not the brain. The thalamus has multiple functions especially related
to the senses.
PTS: 1 DIF: M REF: 335 KEY: UNDERSTANDING
64. ANS: D
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Skeletal muscle contractions and pressure changes during breathing create conditions that propel blood
upward toward the heart. These are called the skeletal muscle pump and the respiratory pump. One-way
valves in medium-sized veins below the level of the heart prevent the backward flow of blood from gravity.
Peripheral resistance and the thickness of the tunica media are factors primarily affecting arterial dynamics;
they do not play a role in returning venous blood to the heart.
PTS: 1 DIF: M REF: 337 KEY: ANALYZING
65. ANS: C
Right-sided heart failure causes blood to back up into the veins and capillaries, which increases capillary
filtration and, therefore, edema. The increased pressure forces fluid out of the capillaries faster than it can be
reabsorbed. Edema caused by reduced capillary reabsorption is a result of low albumin levels, which decrease