Chapter 15
If a person has a blood pressure of 120/80, her mean arterial pressure would be
93 mm Hg.
________ is an increase in blood flow that accompanies an increase in metabolic activity.
Active hyperemia
The continual movement of fluid through the interstitial space functions to
All of the answers are correct
are also known as the pressure reservoir of the cardiovascular system
Arteries
Which type of vessel changes most to regulate resistance to blood flow. Why?
Arterioles because of the large amount of smooth muscle in their walls.
Given that there is a baroreceptor reflex to regulate blood pressure, how is it possible for blood pressure to remain elevated in individuals diagnosed with chronic hypertension?
Baroreceptors adapt to the higher blood pressure, down-regulating their response.
If a person's lymph vessels suddenly vanished (an impossible scenario), what impact would this have on the circulatory system?
Blood volume and blood pressure would decrease
Each of the following paracrines may cause vasodilation EXCEPT
Ca2+.
What does the total blood flow through ALL of the bodies arterioles equal?
Cardiac output
Which changes in paracrines cause vasodilation? What is the result?
Decreased O2, increased CO2, increased H+, increased NO, result in increased blood flow.
Which blood vessel layer secretes paracrine factors, which participate in the regulation of blood pressure and blood vessel growth?
Endothelium
________ capillaries are very porous and allow high volumes of fluids to pass through them, whereas ________ capillaries consist of more tightly joined cells that allow a high degree of selective materials to pass.
Fenestrated, continuous
Bulk flow refers to the mass movement of fluid between the blood and the interstitial fluid. Which of the following statements is not correct concerning bulk flow?
In a typical capillary, overall bulk flow transitions from net absorption on the arterial end to net filtration on the venous end.
If there were a sudden increase in blood volume, what would the baroreceptors do and what would be the effect of that reflex?
Increase firing rate; decrease contractility
What causes active hyperemia?
Increased metabolism results in a local increase in CO2.
Which set of changes correctly describes the baroreceptor reflex in response to increased blood pressure?
Increased vessel diameter, decreased resistance, decreased cardiac output
What effect would an increase in venous tone have on mean arterial pressure?
It would increase it by shifting blood from the veins into the arteries.
The turbulent flow of blood causes a noise called a ________ that can be heard through the stethoscope when taking blood pressure.
Korotkoff sound
White blood cells are generally too large to pass through capillaries. What route must they follow to move from the arterial to the venous circulation?
Metarterioles
Under what circumstance would the heart produce significant levels of adenosine?
Myocardial hypoxia
Blood pressure can be measured with a sphygmomanometer. When the display indicates diastolic pressure, what is heard through the stethoscope. Why?
Nothing is heard because blood flow is smooth through the fully open artery.
What effect would an increase in blood volume have on the resistance to blood flow?
Nothing, they are not directly linked.
Using a sphygmomanometer, a nurse measures a patient's blood pressure as 134/86. What is the patient's pulse pressure and mean arterial pressure?
PP = 48 mm Hg and MAP = 102 mm Hg
Which is the correct relationship between pressure, flow, and resistance?
Pressure ∝ Flow × Resistance
What maintains the driving pressure on blood while the heart is not contracting (ventricular diastole)?
Recoil of the elastic arteries
What is the mechanism by which bulk flow occurs at the capillaries?
Relatively higher hydrostatic pressure on the arterial end of the capillary and relatively higher colloid oncotic pressure on the venous end results in net flow out of the capillary.
What determines the blood flow through individual blood vessels in a local system of vessels?
Resistance in each vessel
Which paracrine acts as a vasoconstrictor?
Serotonin
What type of tissue, present in the walls of blood vessels, allows for regulation of vessel diameter?
Smooth muscle
Why is the velocity of blood lowest in the capillaries as compared to all other types of vessels?
The capillaries have the largest cross sectional area.
Mean arterial pressure is equal to diastolic pressure plus one-third of the pulse pressure. An equivalent equation is MAP = 2/3 DBP + 1/3 SBP. Why is diastolic blood pressure a larger component of MAP than systolic blood pressure?
The heart spends more time in diastole than systole; therefore, the equation reflects the difference in time.
What is the role of the kidney in blood pressure regulation?
The kidney can eliminate water to decrease blood volume or it can conserve water to maintain blood volume.
If a person is bedridden for several days, the baroreceptor reflex may fail upon standing. Why?
The kidneys have reduced the blood volume
What compensatory mechanisms are available to help maintain blood pressure when a large volume of blood is lost, such as during a hemorrhage?
Vasoconstriction, increased thirst, and decreased renal fluid output in the urine
Which syndrome is consistent with a big increase in parasympathetic activity leading to widespread vasodilation and fainting.
Vasovagal syncope
What is the mechanism behind myogenic autoregulation in vascular smooth muscle?
When cells stretch, mechanically gated cation channels open depolarizing the cell resulting in contraction
All of the following would cause an increase in blood pressure EXCEPT
a decrease in cardiac output.
For a diagnosis of hypertension, a patient must have
a systolic pressure above 140 mm Hg or a diastolic pressure above 90 mm Hg.
Venules are similar to capillaries: they have ________ epithelium and only small amounts of ________.
a thin exchange, connective tissue
Smooth muscle is present in the walls of
all vessel types except capillaries.
Blood pressure is highest in the ________ and decreases continuously as blood flows through the circulatory system, due to ________.
arteries, resistance from vessel walls
The cardiovascular control center in the brain can directly cause
arterioles to dilate or constrict and the heart rate to increase or decrease.
The vessels that are the main site of variable resistance in the circulatory system, and that contribute more than 60% of the total resistance, are the
arterioles.
Stretch-sensitive mechanoreceptors known as ________ are located in some artery walls.
baroreceptors
Receptors that monitor blood pressure are called
baroreceptors.
Which of these does NOT increase the risk for cardiovascular disease?
being a female over 30 but under 55
Tom suffers from hypertension (high blood pressure). Which of the following might help deal with his problem? A drug that
blocks beta receptors in cardiac muscle tissue.
Perfusion is
blood flow through an organ
Which of the following is occurring during systole?
blood pressure increases and more stress is placed on arterial walls
Which of the following is greater?
blood pressure when sympathetic stimulation to the heart increases
Which of the following is greater?
blood pressure when the peripheral vessels constrict
Blood pressure and cardiac output can be altered according to
body temperature, emotional responses, and blood oxygen levels.
Which of the following is/are (a) possible treatment(s) for hypertension?
calcium channel blockers and ACE inhibitors
Angiostatin and endostatin may be useful in the treatment of
cancer.
Blood velocity is lowest in the ________.
capillaries
Sinusoids are modified vessels that replace ________ in some tissues.
capillaries
Blood pressure and flow to the brain are monitored by receptors located in the wall of the
carotid artery
A rupture of a blood vessel in the brain is called a(n) ________ and may cause the loss of neurological function commonly called ________.
cerebral hemorrhage, stroke
When blood pressure is normal, the receptors in arterial walls fire action potentials
continuously
When blood pressure receptors sense a loss of blood pressure, they ________ their firing rate.
decrease
Increased levels of carbon dioxide in the blood will result in
decreased parasympathetic stimulation of the heart.
The lipid material of an atherosclerotic plaque accumulates
deep to the tunica intima in the arterial wall
Loss of pericytes around retinal capillaries is a hallmark of the disease
diabetic retinopathy.
Mean arterial pressure is ________ proportional to cardiac output and ________ proportional to resistance of arterioles.
directly, directly
Which of the following conditions would have the greatest effect on peripheral resistance?
doubling the diameter of a vessel
The accumulation of fluid in the interstitial space is called
edema.
A parasitic condition resulting in extreme enlargement of one or both legs is called
elephantiasis.
The lymphatic system
empties the lymph vessels into the veins near the clavicles.
Capillary exchange involving movement through the cells is called ________ transport.
endothelial
The inner lining of blood vessels is called
endothelium
Capillary walls consist of ________, supported on a cellular matrix called ________.
endothelium, the basal lamina
Due to the differences in opposing forces, there is net ________ occurring at the arteriolar end of most capillaries, coupled with net ________ at the venous end.
filtration, absorption
Differences between arterioles and metarterioles include the fact that arterioles
have a continuous smooth muscle layer in their walls.
Which of the following is greater?
heart rate during circulatory shock
The term for chronically elevated blood pressure is
hypertension.
Reactive hyperemia is
increased blood flow following a period of reduced blood flow.
If cardiac output increases and resistance in arterioles does NOT change, what happens to arterial blood pressure?
increases
Increased blood volume ________ blood pressure.
increases
The mean arterial pressure (MAP) is important because
it represents the driving pressure for blood flow.
Which organ is NOT part of the cardiovascular system and plays an important role in regulating blood pressure?
kidney
Blood flow to a tissue will increase if the
level of carbon dioxide at the tissue increases
At rest, the majority of blood flows through the ________
liver and digestive tract
Reactive hyperemia is triggered by
local accumulation of paracrines due to reduced blood flow.
The matching of blood flow to the changing metabolic needs of a tissue is due to
local control.
Restoring lost fluid from the capillaries back to the circulatory system is one of the major functions of the ________ system.
lymphatic
Blood pressure is determined by
measuring the force exerted by blood in a vessel.
The integrating center for neural control of blood pressure resides in the
medulla oblongata
Regarding the cardiovascular system, the main role(s) of the kidneys is/are to
minimize fluid loss from the blood and therefore maintain blood pressure and reduce blood volume and therefore reduce blood pressure.
Compared to arteries, the velocity of flow of the blood through the capillaries is
much slower.
Osmotic pressure resulting from presence of plasma proteins in blood is called ________ pressure.
oncotic and colloid osmotic
The osmotic pressure created by the presence of proteins is known as ________, which is _________ in the plasma than in the interstitial fluid.
oncotic pressure, higher
The decrease in blood pressure upon standing is known as
orthostatic hypotension.
Capillary exchange involving movement between the endothelial cells is called the
paracellular pathway.
Cerebral capillaries are surrounded by ________ and glial cells and have tight junctions that create the ________.
pericytes, blood-brain barrier
The highly branched contractile cells that regulate capillary permeability are called
pericytes.
The structures that regulate blood flow into single capillaries within a tissue are
precapillary sphincters.
The elevated blood pressure that sometimes accompanies pregnancy is known as
preeclampsia
The difference between the systolic and diastolic pressures is called the
pulse pressure
The values obtained when measuring blood pressure, such as 120/80,
reflect the pressure in the major arteries during ventricular systole and diastole.
Several blood-borne chemicals affect the lumen size of arterioles. Which are NOT paired correctly?
serotonin vasodilation
The bone marrow, the liver, and the spleen do NOT have traditional capillaries. Instead, they have modified vessels called ________ that are ________ than a capillary.
sinusoids, wider
Venous return to the heart is aided by the
skeletal muscle pump and the repiratory pump.
Myogenic autoregulation means that
stretched smooth muscle in a blood vessel constricts reflexively.
When the baroreceptor reflex is triggered by a decline in blood pressure,
sympathetic activity increases and cardiac output increases.
In order to cause vasodilation of most vascular smooth muscle,
sympathetic stimulation is removed
Compensation for decreased blood volume includes increases in
sympathetic stimulation to blood vessels, sympathetic stimulation of the heart, and water conservation by the kidneys.
Angiogenesis is
the growth of new blood vessels.
Edema is likely to occur when
the heart becomes an insufficient pump.
Fenestrated capillaries are present in
the liver.
The rapid pressure increase that occurs when the left ventricle pushes blood into the aorta can be felt as
the pulse.
Malnutrition can cause edema because
there are not enough nutrients for plasma protein synthesis.
The endothelium of the blood vessels and its adjacent connective tissue make up the ________, which is surrounded by layers of smooth muscle and connective tissue called ________.
tunica intima, tunica media
Norepinephrine binding to alpha receptors on vascular smooth muscle causes ________ and epinephrine binding to alpha receptors on vascular smooth muscle causes ________.
vasoconstriction, vasoconstriction
Each of the following factors would increase peripheral resistance except one. Identify the exception.
vasodilation
Fainting is also known as
vasovagal syncope
The only blood vessels whose walls permit exchange between the blood and the surrounding interstitial fluids are the
venules and capillaries
During the fight-or-flight reaction, epinephrine is released from the adrenal medulla and binds to ________ receptors on the vascular smooth muscle of heart, liver, and skeletal muscle arterioles and results in ________ blood flow to these organs; epinephrine can also bind to ________ receptors on other tissues, causing ________ blood flow to these organs.
β2, increased, α, decreased
