Ch. 14 Review Blood Vessels, Blood Flow, and Blood Pressure
Given the following information, calculate the net filtration pressure: capillary hydrostatic pressure = 30 mmHg, interstitial fluid hydrostatic pressure = 5 mmHg, capillary oncotic pressure = 25 mmHg, and interstitial fluid oncotic pressure = 10 mmHg.
10 mm Hg, favoring filtration
The flow equation is: flow = pressure gradient * resistance
False
Which equations correctly relates flow, pressure, and resistance?
Pressure = Flow * Resistance
The more proteins in blood, the higher the blood viscosity
True
The pressure gradient for blood flow through the systemic circuit is the mean arterial pressure.
True
The chronic elevation in arterial pressure (hypertension) that occurs in any individuals results in ___.
a gradual increase in pressure that resets the baroreceptor
The high compliance of veins allows them to ___.
accommodate large volumes of blood with little change in pressure
During exercise, carbon dioxide produced by muscle cells causes vasodilation in skeletal muscle. This is an example of ___.
active hyperemia
What is an increase in blood flow in response to an increase in tissue metabolic activity called?
active hyperemia
Which is an important vasodilator in coronary arteries?
adenosine
Fenestrated capillaries are unique in their ability to ___.
allow relatively large molecules to pass between endothelial cells
What type of adrenergic receptor is found in the smooth muscle of most systemic arterioles?
alpha only
The increase in stroke volume that occurs during exercise is caused primarily by ___.
an increase in myocardial contractility
Which will NOT occur as a consequence of the activation of the baroreceptor reflex that would occur in response to an increased heat load within the body?
an increase in resistance within the skin vasculature
Which can cause vasoconstriction?
angiotensin II
___ are responsible for the detection of mean arterial pressure.
arterial baroreceptors
The pulsatile nature of blood pressure is greatest in which blood vessels?
arteries
Blood flow velocity is greatest in the ___ and slowest in the ___.
arteries; capillaries
In the circulatory system, the largest pressure drop occurs across which blood vessels?
arterioles
Resistance to blood flow is regulated primarily by what blood vessels?
arterioles
The contractile activity of smooth muscle cells within which type of blood vessel is primarily involved in the control of the organ blood flow and mean arterial pressure?
arterioles
Due to their location, baroreceptors in the large systemic veins and the heart function primarily to monitor ___.
blood volume
Which is NOT altered within seconds to minutes of the baroreceptor reflex being activated?
blood volume
Which is an inaccurate description of autonomic innervation of the cardiovascular system?
both sympathetic and parasympathetic neurons innervate smooth muscle in arterioles
Which structures contains high pressure baroreceptors?
both the aortic arch and carotid sinus
What region of the cardiovascular system contains valves?
both the heart and veins
Blood pressure is usually estimated from indirect measurements of the pressure in what structure?
brachial artery
What organ has capillaries that are the most restrictive to movement of hydrophilic solutes?
brain
An increase in sympathetic nervous activity to arterioles will have little effect on the vasculature of the ___.
brain and heart
The total cross-sectional area is greatest in which blood vessels?
capillaries
Under normal conditions, which Starling forces favor filtration?
capillary hydrostatic pressure and interstitial fluid osmotic pressure
Which is an INCORRECT description of a blood vessel type?
capillary walls are comprised of only two cell layers, minimizing the distance for exchange
Which would cause relaxation of precapillary sphincters?
carbon dioxide
Which equations is correct?
cardiac output = stroke volume * heart rate
An increase in arterial carbon dioxide levels activates ___, which causes a ___ in heart rate and a ___ in total peripheral resistance.
chemoreceptors; decrease; decrease
What is/are the components of a blood vessel's extracellular matrix that provides the tensile strength required to withstand pressure?
collagen
What is a measure of the change in vascular volume as pressure within the vessel is altered?
compliance
Which would increase blood flow through a capillary bed?
contraction of smooth muscle in met arterioles bypassing the capillary bed
Which best classifies the baroreceptor reflex?
cranial; autonomic; innate; polysynaptic
Which can cause edema?
damage to capillary walls only
Drugs that block angiotensin-converting enzyme would cause which?
decrease mean arterial pressure
Which would NOT increase mean arterial pressure?
decreased parasympathetic activity to the arterioles
Mean arterial pressure can be increased by all except ___.
decreasing end-diastolic volume
Glucose moves across continuous capillary walls by what mechanism?
diffusion
The primary mechanism for exchange of substances across the capillary wall is ___.
diffusion
What component of artery walls allows them to store energy that is later used to maintain continuous blood flow through the circulatory system?
elastin
An increase in the volume of blood ejected from the heart, with no change in total peripheral resistance, would ___.
elevate mean arterial pressure
An increase in total peripheral resistance, in the absence of any change in cardiac output, would ___.
elevate mean arterial pressure
The lumen of every blood vessel is lined by a monolayer of what cell type?
endothelial cells
Which substance is secreted by endothelial cells and causes vasoconstriction?
endothelin-1
___ describes the movement of fluid out of the capillary, while ___ describes the movement of fluid into the capillary.
filtration; absorption
Valves, which are ___, maintain the unidirectional movement of blood, thereby facilitating the return of blood to the heart.
found only in peripheral veins
As mean arterial pressure increases, the ___, informing the medulla oblongata that blood pressure has indeed increased.
frequency of action potentials from the baroreceptors increases
During exercise, which tissues receive less blood flow compared to resting conditions?
gastrointestinal tract only
In comparison to the systemic circuit, the pulmonary circuit ___.
has lower resistance to blood flow
Which correctly describes sympathetic control of blood vessels in the skin during thermoregulation?
heat causes a decrease in sympathetic activity, resulting in vasodilation
What is a decrease in tissue oxygen called?
hypoxia
Which would decrease mean arterial pressure?
increase in arteriole diameter
The increase in blood flow to active skeletal muscle relative to other organs is largely caused by the ___.
increase in local metabolic factors within the muscle
In response to a decrease in tissue metabolic activity, tissue oxygen concentrations ___, which causes a ___.
increase; constriction of the arterioles
The reduction in organ blood flow that results from a decrease in mean arterial pressure would be exacerbated by the ___ that occurs as a consequence of the baroreceptor reflex.
increased peripheral resistance
Which would increase the rate of blood flow through a blood vessel?
increased pressure of the blood entering the vessel
Which will NOT occur in response to a decrease in the extent of stretch detected by a baroreceptor?
increased urine flow
Which is NOT a mechanism that alerts the balance between filtration and absorption in the body?
increasing hydrostatic pressure gradient in cases of enhanced interstitial protein
In cardiac and skeletal muscle vasculature, the distribution of alpha and beta receptors are such that epinephrine will ___.
induce a dilation that increases blood flow to these tissues
Which inaccurately represents normal forces across capillary walls?
interstitial fluid hydrostatic pressure increases from arteriole end to venous end.
Arteries have ___ compliance and ___ resistance.
low; low
Foreign materials are filtered out of the lymphatic fluid by what type of cell located within the lymph nodes?
macrophages
What is the driving force for blood flow through the systemic circuit?
mean arterial pressure
Information about mean arterial pressure is integrated within what area of the central nervous system?
medulla oblongata
Where is the cardiovascular control center?
medulla oblongata
A decrease in pressure within an arteriole will initiate a ___.
myogenic response
Which comparisons between systemic capillaries and lymphatic capillaries is true?
net filtration occurs across systemic capillaries; net absorption occurs across lymphatic capillaries
Which substance is secreted by endothelial cells and causes vasodilation?
nitric oxide
Which accurately compares active hyperemia to reactive hyperemia?
one is caused by increased metabolic activity, the other in response to release of an occlusion to blood flow.
An increase in the concentration of which within the interstitial space surrounding an arteriole would cause that vessel to constrict?
oxygen
Which chemical's concentration is NOT increased by an elevation in metabolic activity?
oxygen
The elastic nature of the largest blood vessel's walls allows them to act as a ___, maintaining the driving force for blood flow while the heart is relaxed during diastole.
pressure reservoir
The portion of osmotic pressure exerted by ___ in the blood is known as colloid osmotic pressure.
proteins
A person goes to the doctor and is told his blood pressure is 90/60 and his pulse is 80. Which is FALSE?
pulse pressure is 80 mm Hg
The respiratory pump facilitates the return of blood to the heart by ___.
raising the pressure gradient between abdominal and thoracic veins during inspiration
Which is NOT a mechanism that enables molecules to move across capillary endothelial cells?
rapid diffusion of water-soluble molecules across endothelial cells
What is the purpose of extrinsic control of arteriolar smooth muscle contractile activity?
regulate mean arterial pressure
The effects of epinephrine on vascular resistance are dependent upon which?
relative distribution of alpha and beta receptors
Chemicals released by metabolically active cells will cause?
relaxation of arteriolar smooth muscle to increase blood flow
Any change in the relative distribution of cardiac output to an organ is typically due to changes in which?
resistance of that organ's vascular bed
Which describes rhythmic changes in sympathetic and parasympathetic activity that affect heart rate coincident with respiration?
respiratory sinus arrhythmia
Arteriolar smooth muscle in what tissue tends to have beta2 receptors?
skeletal muscle
During exercise, which organs receive an increase in the proportion of cardiac output delivered to it?
skeletal muscle, heart, and skin
Which would decrease central venous pressure?
standing up
At rest, the greatest proportion of blood volume is present within the ___.
systemic veins
The long-term regulation of arterial blood pressure involves ___.
the control of blood volume by the kidneys
Given that the net filtration of fluid out of the capillaries averages about 3 liters per day, how is blood maintained in light of this apparent fluid loss?
the lymphatic system returns filtered fluid is returned to the blood
Which statements about smooth muscle in arterioles is FALSE?
the muscle is multi-unit smooth muscle
Which does NOT occur in response to baroreceptors detecting an increase in mean arterial pressure?
vasoconstriction
The hormone vasopressin acts in the short term to ___ and in the long term to ___, thereby increasing mean arterial pressure.
vasoconstriction arterioles; decrease urine outflow
Which is NOT a component of the microcirculation?
veins
The blood vessels of largest diameter are the ___; the blood vessels with the thickest walls are the ___.
veins; arteries
Exchange between blood and interstitial fluid occurs across capillaries and, to a lesser extent, ___.
venules
Veins functions as ___ reservoirs due to their ___ compliance.
volume; high
