Physio - CH14 The Cardiovascular System: Blood Vessels, Blood Flow, and Blood Pressure

Within a capillary at the arteriole end, the following pressures are measured: a filtration pressure of 42 mmHG an absorption pressure of 28 mmHG The net filtration pressure (NFP) for this capillary is ________ mmHg. A)14 B)70 C)28 D)42

A)14 Within a capillary at the arteriole end, the following pressures are measured: A filtration pressure of 38 mmHg An absorption pressure of 26 mmHg The net filtration pressure (NFP) for this capillary is 14 mmHg. NFP is the difference between the filtration and absorption pressures. In this example, 38 mmHg less 26 mmHg is 14 mmHg.

Hypertension can be caused by ________. A)All of the listed responses are correct. B)genetics C)kidney disease D)hormone imbalance

A)All of the listed responses are correct. All of the listed responses are correct. Hypertension can be caused by genetics, kidney disease, or hormone imbalance (as well as many other factors that are not listed). Hypertension is a term that refers to blood pressure measurements for systolic and diastolic pressure in excess of the target normal values of 120/80. It is fairly typical and not a cause for concern as long as it is transient and does not occur for extended periods of time without accompanying physical activities. Chronic hypertension represents periods of hypertension for extended periods of time. Among the common causes for primary hypertension are obesity, high cholesterol, smoking, and genetic predisposition. Kidney disease, which is associated with difficulties maintaining water, electrolyte, and osmotic equilibrium, is a recognized cause of secondary hypertension. Additionally, endocrine hypertension is associated with abnormal levels of various hormones in the blood, which interfere with normal regulatory mechanisms used in blood pressure control and MAP.

By which mechanism are small, water-soluble substances transported across a capillary from the blood plasma to the interstitial fluid? A)By simple diffusion through capillary pores. B)They cannot be transported. C)By transcytosis. D)By simple diffusion through endothelial cell membranes.

A)By simple diffusion through capillary pores. Small, water-soluble substances are transported across a capillary from the blood plasma to the interstitial fluid by simple diffusion through capillary pores. Due to solubility limitations, water-soluble substances ,such as ions, cannot simply diffuse through endothelial cell membranes. Additionally, as transcytosis requires energy, the transcytosis of small, water-soluble substances that are small enough to diffuse through capillary pores would not be efficient. Capillary exchange mechanisms are summarized in the image below.

By which mechanism are exchangeable proteins transported across a capillary endothelial cell? A)By transcytosis B)By simple diffusion through capillary pores C)By simple diffusion through endothelial cells D)They cannot be transported.

A)By transcytosis Exchangeable proteins are transported across a capillary endothelial cell by transcytosis. Some proteins are selectively transported to the interstitial fluid. As most proteins are too large to fit through the capillary pores and are incapable of simply diffusing through the endothelial cells, only those which are transcytosed across an endothelial cell are capable of entering the interstitial fluid. Other proteins will remain within the blood plasma. Capillary exchange mechanisms are summarized in the image below.

Capillaries contain which of the following structures? A)Endothelium B)Elastic connective tissue C)Fibrous connective tissue D)Smooth muscle

A)Endothelium Capillaries contain endothelium. Structurally speaking, capillaries are the simplest of all blood vessels in the body. They are very thinly walled vessels composed entirely of a single layer of simple squamous epithelial cells, making them very well suited for filtration and reabsorption. There is no connective tissue of any kind in the walls of capillaries, nor is there any smooth muscle. The anatomical comparison of the blood vessels is illustrated in the image below.

As part of the baroreceptor reflex response to hemorrhage, which of the following increases? A)Heart rate and total peripheral resistance B)Vasodilation and heart rate C)Urine output and vasodilation

A)Heart rate and total peripheral resistance Heart rate and total peripheral resistance increase as part of the baroreceptor reflex response to hemorrhage. A hemorrhage situation refers to a major, significant loss of blood, which causes an extreme decline in blood volume results and leads to a decline in mean arterial pressure (MAP). The image below illustrates each of the physiological responses to a loss of blood volume. The purpose is to restore a more normal MAP, which sustains blood flow and delivery of blood to the most important and highest priority locations in the body. Urine output is due to the vasoconstriction, and the amount of vasodilation also decreases.

Which of the following terms could be used to characterize veins? A)High compliance and volume reservoir B)Low compliance and high resistance C)Pressure reservoir and high resistance

A)High compliance and volume reservoir The terms high compliance and volume reservoir could be used to characterize veins. In blood vessels the term compliance refers to an increase in volume that occurs when the pressure in that vessel is increased. The compliance in veins is estimated to be approximately 30 times higher than it is in arteries. With reduced blood flow and pressure, blood also tends to accumulate more readily in veins, as it is on the return leg of the cardiovascular circuit to the heart. The comparative lack of smooth muscle and subsequently, significantly less vasoconstrictive activity, means a decrease in resistance rather than an increase. The relationship between greater compliance and volume reserve are illustrated in the plots below. Veins hold more blood when compared to arteries due to their compliant nature.

Blood flow is increased to skeletal and cardiac muscle during exercise by ________. A)active hyperemia B)flow autoregulation C)epinephrine binding to alpha receptors D)acetylcholine binding to nicotinic receptors

A)active hyperemia Blood flow is increased to skeletal and cardiac muscle during exercise by active hyperemia. Active hyperemia can be explained in terms of an increased metabolic rate increases the demand for oxygen which then increases the need to remove metabolic wastes (i.e., carbon dioxide). Epinephrine is not directly involved in this pathway as it is a locally controlled event. Acetylcholine is not directly involved in this pathway as it is a locally controlled event. Flow autoregulation is characteristic of reactive hyperemia

Bulk flow across a capillary is the combination of ________ (which allows for transport of water and solutes from the blood plasma to the interstitial fluid) and ________ (which allows for transport of water and solutes from the interstitial fluid to the blood plasma). A)filtration; absorption B)active transport; passive transport C)absorption; filtration D)passive transport; active transport

A)filtration; absorption Bulk flow across a capillary is the combination of filtration (which allows for transport of water and solutes from the blood plasma to the interstitial fluid) and absorption (which allows for transport of water and solutes from the interstitial fluid to the blood plasma). Passive and active transport mechanisms may be used for solute transport, but these terms alone do not encompass the net solute and water transport between the blood plasma and interstitial fluid. The directionality of filtration and absorption is demonstrated in the image below. Note the arrow directionality beneath each component. During filtration, solutes and water are moving more outward while during absorption, solutes and water are moving more inward.

A change in vascular resistance in response to stretch of blood vessels is called ________. A)myogenic response B)mean arterial pressure C)vasodilation D)cardiac output

A)myogenic response A change in vascular resistance in response to stretch of blood vessels is called myogenic response. This control of vascular resistance leads to a change in blood flow through an arteriole, so that tissue perfusion is maintained within homeostasis. Myogenic response may result in vasodilation if the blood flow is too low, but by itself does not define the myogenic response. This is due to the fact that the myogenic response may be vasoconstriction if blood vessels stretch in response to increased perfusion. Cardiac output is directly related to the rate of blood ejected from the heart. Mean arteriole pressure is a measure of arteriole pressure, which is detected by the stretch-sensitive fibers at work during a myogenic response.

Congestive heart failure on the left side of the heart results in ________. A)pulmonary edema B)a net filtration of zero in the systemic capillaries C)systemic edema

A)pulmonary edema Congestive heart failure on the left side of the heart results in pulmonary edema. Although the human cardiovascular system is a closed system, blood pressure and blood flow from the left ventricle are affected most in the systemic circuit. The left ventricle does, however, provide the initial push of blood responsible for delivery of blood to the tissue capillaries, and it is instrumental in driving venous return that then travels through the heart's right side and to the pulmonary circuit. If the left ventricle fails, capillary exchange in the lungs fails to absorb interstitial fluid as normal and pulmonary edema results. Net filtration can still occur across the systemic capillaries, therefore it is not at zero. Systemic edema results when the right side of the heart fails, causing a rise in systemic capillary pressure and inability to reabsorb systemic interstitial fluid.

The sequence of negative feedback events that use baroreceptors to keep blood pressure within set-point is referred to as ________. A)the baroreceptor reflex B)hormonal control C)hypertension D)thermoregulatory reflex

A)the baroreceptor reflex The sequence of negative feedback events that use baroreceptors to keep blood pressure within set-point is referred to as the baroreceptor reflex. Arterial baroreceptors (pressure monitoring) provide information to the cardiovascular control center (CCC) of the medulla oblongata. Depending on the pressure, either the sympathetic or parasympathetic nervous system is activated to bring blood pressure back to set-point. Hypertension may result if the baroreceptor reflex is not functioning properly. The thermoregulatory reflex is used for temperature homeostasis. Hormonal control uses epinephrine to alter cardiac output (CO) and stroke volume (SV), and vasopressin and angiotensin II to alter total peripheral resistance (TPR) and mean arterial pressure (MAP). The baroreceptor reflex is summarized in the figure below.

The total flow rate of blood is ________ in the arterial system compared to the venous system, while the velocity of flow is ________ in arteries compared to veins of comparable size. A)the same; greater B)greater; the same C)the same; lesser D)None of the listed responses is correct. E)lesser; the same

A)the same; greater The total flow rate of blood is the same in the arterial system compared to the venous system, and the velocity of flow is greater in arteries compared to veins of comparable size. Flow rate is defined as the amount of blood that travels through the cardiovascular system at any given point. An example of flow rate is cardiac output. The cardiac output in the arteries and the veins is the same for a single cardiac cycle. The velocity of flow, however, is different. As blood moves through the system, it encounters resistance and loses energy. The loss of energy results in a loss of speed, and therefore velocity of blood flow is less in the veins than it is in the arteries. It is slowest in the capillary beds because of the huge cross-sectional area. The velocity of blood flow through the vasculature is plotted in the lower, purple plot of the image below.

A decrease in which of the following would also cause mean arterial pressure (MAP) to decrease? A)Heart rate B)All of the listed responses are correct. C)Stroke volume D)Total peripheral resistance

B)All of the listed responses are correct. All of the listed responses are correct. A decrease in either stroke volume, total peripheral resistance, or heart rate would also cause mean arterial pressure to decrease. MAP is the average pressure in the arteries throughout the cardiac cycle. It can be calculated by using the following formula, where HR is heart rate, SV is stroke volume, and TPR is total peripheral resistance: MAP = HR x SV x TPR

Which category of blood vessel has the thickest layers of elastic tissue and smooth muscle? A)Capillaries B)Arteries C)Veins D)Arterioles

B)Arteries Arteries have the thickest layers of elastic tissue and smooth muscle. They rely heavily on a smooth muscle layer and elastic connective tissue as they need to stretch and recoil as blood pulses through them. This stretching as blood pulses through increases the pressure is due to the low compliance of the arteries and contributes to the pressure reservoir. In comparison, veins are not as elastic as arteries, but they are more compliant. Venules are not as elastic, and they are much thinner. Arterioles are types of small arteries, but they are not as elastic as arteries. Capillaries are the most permeable of all of the vessels, and they are not elastic. The anatomical comparison of the blood vessels is illustrated in the image below.

________ is the pressure of blood contained in the large veins that lead to the heart. A)Mean arterial pressure B)Central venous pressure C)Stroke volume D)Cardiac output

B)Central venous pressure Central venous pressure (CVP) is the pressure of blood contained in the large veins that lead to the heart. This is considered by most to be the most important factor influencing venous blood return to the right side of the heart. Normally as CVP rises, venous return increases because the increased pressure forces more blood flow into the atria, especially on the right side. Atrial pressure increases, which increases the stretch of the ventricular wall and increases stroke volume and cardiac output. The difference between the MAP and the CVP is the pressure gradient that drives blood flow through the systemic circuit.

Which term is used to describe the hollow interior of some organs, such as blood vessels? A)Capillary B)Lumen C)Epithelium D)Chamber

B)Lumen Lumen is a term used to describe the hollow interior of some organs, such as blood vessels. In blood vessels, the lumen is lined with endothelium tissue. The term chamber is oftentimes used to describe the heart and usually not for other hollow organs. While capillaries do have a lumen, the term capillary is specific to this type of vessel. Hollow organs will likely have an epithelium, but the epithelium tissue does not encompass the hollow space.

What is the function of the skeletal muscle "pump?" A)To increase capillary blood pressure and promote filtration. B)To increase venous blood pressure to return blood to the heart. C)To enhance artery blood distribution and return blood to the heart.

B)To increase venous blood pressure to return blood to the heart. The function of the skeletal muscle "pump" is to increase venous blood pressure to return blood to the heart. Veins possess valves, which allow only forward flow of blood (en route to the heart). Due to the forces of gravity, rising from a position of lying down or sitting directs blood in the vena cava downward, raising the central venous pressure (CVP), but momentarily pooling blood. This blood can be driven forward/upward toward the heart by increasing voluntary muscular activity around veins and venules, which produces a massaging or pumping action on the blood pooling within the vessels. This "pumping" effectively propels blood from sections of the vein separated by the one-way valves into the next segment and ultimately back to the heart. This same activity is exhibited involuntarily each time the muscles of inspiration in the chest contract and relax during a ventilation cycle for the lungs. As long as a person is breathing, the skeletal muscles of the chest help provide venous return. The skeletal muscle pump is illustrated in the image below.

Following filtration of blood plasma, not all solutes are filtered due to their large size, hydrophilic nature, and lack of transcytosis. These nonpermeating plasma solutes contribute to the capillary ________. A)interstitial fluid osmotic pressure B)colloid osmotic pressure C)capillary hydrostatic pressure D)central venous pressure

B)colloid osmotic pressure Nonpermeating plasma solutes contribute to the capillary colloid osmotic pressure. Retained solutes create an inward osmotic force that promotes the next phase of bulk flow: absorption. Central venous pressure describes the pressure gradient used for venous blood distribution. Interstitial fluid osmotic pressure creates a more outward osmotic force, with drives filtration. Capillary hydrostatic pressure is due to the presence of fluid inside the capillary and aids in filtration. These forces that affect the movement of fluid across capillaries are summarized in the table below

In an effort to bring mean arterial pressure back to normal after a hemorrhage, total peripheral resistance ________ because the blood flow to most organs ________. However, blood flow to the ________ and ________ is maintained because these organs are not greatly influenced by the baroreceptor reflex. A)stays the same; stays the same; brain; heart B)increases; decreases; brain; heart C)decreases; increases; muscles; GI tract D)increases; decreases; muscles; heart

B)increases; decreases; brain; heart In an effort to bring mean arterial pressure back to normal after a hemorrhage, total peripheral resistance increases because the blood flow to most organs decreases. However, blood flow to the brain and heart is maintained because these organs are not greatly influenced by the baroreceptor reflex. Recall that the underlying goal in physiological responses is the maintenance of homeostasis. The brain, spinal cord and heart are high-priority organs in terms of maintaining blood supply. Organs such as those in the GI tract and skin are low-priority and have decreased blood flow. If blood pressure is limited due to blood loss, vasoconstriction will counter the loss of blood by reducing blood flow through the leaking, damaged vessel(s). At the same time the resulting decrease in lumen size raises the mean arterial pressure (MAP), driving blood through the system such that blood flow is maintained, while volume is reduced. A number of mechanisms in receiving and processing blood go into effect to make blood available to the locations with the highest priority, so that the most vital functions are sustained through the crisis.

A patient's blood pressure is determined by sphygmomanometry to be 185/117. At what pressure did the Korotkoff sounds disappear and why? A)less than mean arterial pressure B)less than 117 mmHg, because cuff pressure is below diastolic and no longer causes turbulent blood flow C)less than185 mmHg, because the cuff pressure is no longer compressing the artery D)less than 68 mmHg, because cuff pressure must be less than pulse pressure

B)less than 117 mmHg, because cuff pressure is below diastolic and no longer causes turbulent blood flow A patient's blood pressure is determined by sphygmomanometry to be 185/117. At a pressure of less than 117 mmHg, the Korotkoff sounds disappear because cuff pressure is below diastolic and no longer causes turbulent blood flow. Korotkoff sounds appear first to indicate systolic pressure as blood begins to flow through an occluded vessel. The turbulent flow through the vessel is indicated by a thud, in this case the 185 mmHg pressure reading. As one listens, the thuds become softer and softer, until the turbulent flow of blood is absent. The last point at which the thud was heard (at the lowest pressure) represents the diastolic pressure. The diastolic pressure represents the lowest blood pressure due to the non-contractile activity of the ventricles (particularly the left ventricle). An accurate systolic and diastolic pressure must first be measured in order to calculate pulse pressure and mean arterial pressure. The relationship between the Karotkoff sounds and blood pressure measurement are shown in the image below.

In active hyperemia ________. A)decreased blood flow causes arteriolar smooth muscle to relax and vasodilate B)low oxygen levels cause arteriolar smooth muscle to relax and vasodilate C)the autonomic nervous system controls arteriolar smooth muscle to relax and vasodilate D)stretching blood vessel walls tends to make them constrict

B)low oxygen levels cause arteriolar smooth muscle to relax and vasodilate In active hyperemia, low oxygen levels cause arteriolar smooth muscle to relax and vasodilate. Oxygen is consumed during increased tissue activity, which leads to vasodilation, decreased resistance, and increased blood flow to elevate tissue oxygen availability and reduce carbon dioxide concentrations from the tissue. As this process is controlled locally, the autonomic nervous system is not involved. Furthermore, there is an increase (and not a decrease) in blood flow during increased tissue activity. The negative feedback events in active hyperemia are shown in the image below.

Control of mean arterial blood pressure by the central nervous system is controlled primarily by the ________. A)vagus nerve B)medulla oblongata C)cerebral cortex D)hypothalamus

B)medulla oblongata Control of mean arterial blood pressure by the central nervous system is controlled primarily by the medulla oblongata. The cardiovascular control center is located in the medulla oblongata to activate sympathetic or parasympathetic nerves, which target the heart and blood vessels and keep MAP within a homeostatic range. The hypothalamus and cerebral cortex play a role in control of MAP, but not as directly as the medulla oblongata. The vagus nerve is an efferent peripheral nerve that provides parasympathetic control to the heart. The role of the medulla oblongata in MAP regulation is illustrated in the image below.

Fenestrated capillaries are found in organs that ________. A)have a very restricted blood flow B)need rapid diffusion of solutes C)need to limit solute diffusion into organs D)have been damaged due to disease

B)need rapid diffusion of solutes Fenestrated capillaries are found in organs that need rapid diffusion of solutes. In fenestrated capillaries, relatively large intercellular pores are found between adjacent epithelial cells of the capillary. The larger pore size allows this exchange surface to rapidly exchange water-soluble substances and relatively large proteins; these are found mainly in the organs where the rapid exchange of materials across the capillary wall is required. Fenestrated capillaries are well known constituents of kidneys, small and large intestines, and endocrine glands as well as the liver and lymphatic tissues. Therefore, fenestrated capillaries would not be found in organs that need to limit solute diffusion, have a restricted blood flow, or have been damaged due to disease. An example of a fenestrated capillary is compared to a continuous capillary in the image below.

As blood flows through the systemic circuit, in which vessels will velocity and pressure undergo the greatest decline? A)Capillaries B)Venules C)Arterioles D)Arteries E)Veins

C)Arterioles Velocity and pressure undergo the greatest decline in the arterioles. Systemic pressure changes are plotted in the graph below. Note that pressure is greatest in the arteries and least in the veins. However, the steepest decline in pressure occurs at the arterioles. Similarly, velocity of blood flow changes throughout the systemic circuit in an inverse relationship to total cross sectional area. Note that the velocity is the greatest as blood enters the systemic circuit in the aorta. A modest decline in velocity takes place along the arteries before the velocity plummets throughout the arterioles. Velocity is plotted in the bottom graph, in purple.

Which part(s) of the heart is (are) innervated by sympathetic nerves? A)Only the myocardium B)Only the SA Node C)Both the SA node and myocardium

C)Both the SA node and myocardium The heart is innervated by sympathetic nerves at both the SA node and myocardium. Sympathetic stimulation at the SA node functions to increase heart rate while increasing contractility at the myocardium. The combined effect is an increased cardiac output (CO). Sympathetic nerves do innervate the aorta, but do not have the sympathetic nerves (shown in green) or the parasympathetic pathways (shown in purple) of the heart, which are illustrated in the image below.

What is the relationship between blood flow and a pressure gradient? A)Indirectly proportionate B)Inversely proportionate C)Directly proportionate

C)Directly proportionate The relationship between blood flow and a pressure gradient is directly proportionate. Blood flow and distribution are dependent upon a pressure gradient to propel blood from the heart, to the tissues, and back to the heart. Therefore, a larger pressure gradient between areas of the vasculature, will allow blood to flow more quickly. One formula used to represent the relationship between blood flow (F), pressure gradient (∆P), and Resistance (R) is given below. If the relationship between blood flow and pressure gradients were inversely proportionate, the rate of blood flow would slow down as the pressure gradient increases. A decline in the rate of blood flow to tissues would not be life sustaining. Indirectly proportionate is not an accepted term to describe relationships and therefore is not a valid option to choose.

Which of the following scenarios would lead to arteriole vasoconstriction in an organ? A)Excessive carbon dioxide levels B)Suppressed oxygen levels C)Excessive blood flow

C)Excessive blood flow Excessive blood flow to an organ would lead to arteriole vasoconstriction in an organ. Excessive blood flow distends an arteriole, stretching smooth muscles in the arteriole to initiate a myogenic response of vasoconstriction. Vasoconstriction refers to the reduction in blood vessel lumen size, which then increases resistance and reduces blood flow to maintain a set-point. In instances of excessive carbon dioxide or suppressed oxygen levels, arterioles would vasodilate to sustain oxygen delivery and carbon dioxide removal to bring these gases within set-point range

What is the effect of mean arterial pressure in the presence of norepinephrine, vasopressin, or angiotensin II? A)All of the listed responses are correct. B)Decreased MAP by causing vasodilation C)Increased MAP by causing vasoconstriction D)No observable effect upon MAP

C)Increased MAP by causing vasoconstriction The effect of mean arterial pressure in the presence of norepinephrine, vasopressin, or angiotensin II is an increased MAP by causing vasoconstriction. Each increase blood vessel total peripheral resistance. Neural and hormonal factors that can control MAP are summarized in the table below.

What is the relationship between blood flow and resistance? A)Indirectly proportionate B)Directly proportionate C)Inversely proportionate

C)Inversely proportionate The relationship between blood flow and a resistance are inversely proportionate. Resistance factors oppose the flow of blood. Therefore, when resistance factors exist in a vessel, blood flow of blood to that particular region of the body will decline. Resistance factors to blood include blood vessel radius, blood vessel length, and blood viscosity. One formula used to represent the relationship between blood flow (F), pressure gradient (∆P), and Resistance (R) is given below. If the relationship between blood flow and resistance were directly proportionate, then resistance factors would enhance blood flow. Indirectly proportionate is not an accepted term to describe relationships and therefore is not a valid option to choose.

During the measurement of blood pressure with a sphygmomanometer, diastolic blood pressure is recorded when ________. A)Korotkoff sounds are first heard through the stethoscope B)turbulent sounds are heard through the stethoscope C)Korotkoff sounds are no longer heard through the stethoscope

C)Korotkoff sounds are no longer heard through the stethoscope During the measurement of blood pressure with a sphygmomanometer, diastolic blood pressure is recorded when Korotkoff sounds are no longer heard through the stethoscope. When measuring peripheral blood pressure, Korotkoff sounds are produced as blood flow is occluded by the blood pressure cuff and then restored as pressure is relieved. The sounds that appear due to turbulent flow initially indicate what is known as the systolic blood pressure. As the sounds diminish in volume this is an auditory indicator of reduced occlusion and less turbulent flow caused by the sphygmomanometer cuff.

During which phase of contraction is blood pressure highest? A)Ventricular diastole B)Arterial systole C)Ventricular systole D)Venous diastole

C)Ventricular systole Blood pressure is highest during ventricular systole. The myocardial (cardiac) muscle of the heart contracts during systole. As the ventricles contract and squeeze the blood, the pressure within them rises so that blood is forced into the pulmonary artery and the aorta. The left ventricle generates the greatest amount of pressure while in systole. Diastole occurs during the quiescent period of the myocardium while a chamber is resting and filling with blood; therefore pressure is minimal.

Differences between arterioles and metarterioles include the fact that arterioles ________. A)allow blood to bypass capillary beds B)have an endothelial lining C)have a continuous smooth muscle layer in their walls D)All of the listed responses are correct

C)have a continuous smooth muscle layer in their walls Differences between arterioles and metarterioles include the fact that arterioles have a continuous smooth muscle layer in their walls. Metarterioles are also known as thoroughfare channels because they are able to functionally re-route blood to bypass capillaries in areas where exchange is not as critical so that blood can be sent to locations with greater needs. The continuous layer of smooth muscle in arterioles permits changes in lumen size, and these changes regulate the flow of blood into capillaries and pre-capillary sphincters, which have the ability to close and re-direct blood into metarterioles rather than capillaries. Each metarteriole and arteriole has an endothelial lining.

Mean arterial pressure (MAP) is based on ________. A)Korotkoff sounds heard through the stethoscope during a blood pressure reading B)systolic blood pressure minus diastolic blood pressure C)heart rate, stroke volume, and total peripheral resistance D)the sum of systolic and diastolic blood pressure

C)heart rate, stroke volume, and total peripheral resistance Mean arterial pressure (MAP) is based upon heart rate, stroke volume, and total peripheral resistance. MAP is the average pressure in the arteries throughout the cardiac cycle. It can be calculated by using the following formula, where HR is heart rate, SV is stroke volume, and TPR is total peripheral resistance: MAP = HR x SV x TPR The sum of systolic and diastolic blood pressure is not used to calculate MAP. The difference between the systolic and diastolic pressures is not used to calculate MAP. The Korotkoff sounds are not used to directly determine MAP. Instead, the Korotkoff sounds can be used to record systolic arterial pressure.

The pressure exerted by fluid within the capillaries is called capillary ________ pressure. A)net filtration B)osmotic C)hydrostatic D)partial gas

C)hydrostatic The pressure exerted by fluid within the capillaries is called capillary hydrostatic pressure. This pressure of water pushes against the vessel wall and aids in filtration. Capillary osmotic pressure is due to nonpermeating proteins driving osmosis and promotes capillary absorption. Partial pressures are most often associated with a particular gas present in a mixture. Net filtration pressure determines the direction of fluid flow and is the difference in all of the forces which promote filtration and absorption. The forces which affect fluid movement across capillaries are summarized in the table below.

In terms of maintaining blood pressure or responding to inevitable fluctuations in blood pressure, when everything is considered, the immediate danger posed by ________, is far greater than that posed by ________. A)hypoglycemia; hyperglycemia B)hypertension; hypotension C)hypotension; hypertension D)hyperglycemia; hypoglycemia

C)hypotension; hypertension In terms of maintaining blood pressure or responding to inevitable fluctuations in blood pressure, when everything is considered, the immediate danger posed by hypotension, is far greater than that posed by hypertension. Lower than normal mean arterial pressure (MAP) can lead to compromised organ function throughout the body, which can lead to permanent damage and loss of function. Higher than normal blood pressure can have damaging effects as well, but this kind of damage usually takes years of constant exposure before it is fatal, while hypotension can do fatal organ damage in only a matter of minutes in a wide array of locations nearly simultaneously. For this reason an immediate assessment of blood pressure and injuries that may be associated with major blood loss are always among the very first assessments made in emergency care situations. Increased heart rate and myocardium contractility. Hypoglycemia and hyperglycemia describe blood levels of sugar that are too high or too low, but do not describe blood pressure fluctuations

At rest, the majority of cardiac output is distributed to ________. A)the brain B)skeletal muscle(s) C)tissue(s) with the greatest metabolic demand D)the largest organ(s)

C)tissue(s) with the greatest metabolic demand At rest, the majority of cardiac output is distributed to the tissue(s) with the greatest metabolic demand. Cardiac output (CO) refers to the blood that is forcefully ejected from the ventricles as in CO = heart rate (HR) x stroke volume (SV). The tissue(s) with the greatest metabolic demand are generally those with highest priority to blood flow and supply. The size of an organ is not the primary determinant of blood flow priority. Skeletal muscle may often experience increased blood flow during peak periods of activity, but this is directly tied to the metabolism of a skeletal muscle. Thus, skeletal muscle does not always receive the majority of CO since its metabolic needs fluctuate with its levels of activity or inactivity. Although the brain should receive a constant CO at rest and at times of exercise, it does not receives the majority of the CO

Functions of the lymphatic system include ________. A)return of fluid accumulated in tissues to venous system B)immunity C)prevention of fluid accumulation in the tissues (edema) D)All of the listed responses are correct

D)All of the listed responses are correct All of the listed responses are correct. Functions of the lymphatic system include prevention of fluid accumulation in the tissues (edema), return of fluid accumulated in tissues to venous system, and immunity. Lymph nodes are found interspersed along the paths for lymph fluid to flow through lymphatic vessels. Lymph nodes act as filters by allowing phagocytic white blood cells stationed there to take specific action against foreign cells and other toxic agents as lymphatic fluid is being redistributed throughout the body and ultimately returned to the vena cavae for fluid reclamation and return to blood plasma. The redistribution of excessive volumes of lymph collected from the interstitial fluid around capillary beds prevents their accumulation and edema. The lymphatic system is represented as the green vessels in the image below.

Blood vessel resistance is dependent on ________. A)blood viscosity B)vessel radius C)vessel length D)All of the listed responses are correct.

D)All of the listed responses are correct. All of the listed responses are correct. Blood vessel resistance is dependent upon vessel radius, vessel length, and blood viscosity. The longer a vessel is (i.e., the more distance blood must travel), the greater the resistance. The more viscous (sticky) the blood is, the more resistance there is. The smaller the internal diameter in the blood vessel, the more resistance there is to blood flow. The relationship of these resistance factors are demonstrated by Poiseuille's Law, where: L is the length of the tube n is the viscosity of the fluid Pi =3.14 r is the tube's internal radius.

Which of the following is (are) the same in both the pulmonary and systemic circuits? A)Pressure gradient B)All of the listed responses are correct. C)Vessel resistance D)Blood flow rate

D)Blood flow rate Blood flow rate is the same in both the pulmonary and systemic circuits. Blood flow rate is defined as the volume of blood flowing through an organ or part, expressed as volume per unit of time. The blood flow rate through each circuit is about 5 L/min. Pressure gradients within the cardiovascular system drive the flow of blood but are in a constant state of flux, given the actions of the heart and blood vessels throughout the body. A pressure gradient of about 85 mmHg MAP (mean arterial pressure) exists in the systemic circuit between the aorta and vena cava. A pressure gradient also exists in the pulmonary circuit between the pulmonary artery and vein. However, the gradient is much lower at about 15 mmHg MAP. Vessel resistance at any given location within the cardiovascular system is subject to increase or decrease due to a number of intrinsic as well extrinsic control factors, and therefore is not constant. It is also important to note that the pulmonary circuit offers less resistance when compared to the systemic circuit.

Which of the following contain one-way valves? A)Only metarterioles B)Only lymphatic vessels C)Only veins D)Both lymphatic vessels and veins E)Only precapillary sphincters

D)Both lymphatic vessels and veins Both lymphatic vessels and veins contain one-way valves. They prevent the backflow of blood and lymph when the pressure is insufficient to propel each toward the heart. Valves alone are not sufficient to return the respective fluids, so veins and lymphatic vessels also employ skeletal muscle "pumps." Metarterioles and precapillary sphincters are functionally more important to the routing of blood into or around capillary beds, and they do not have valves. Venous valves and the skeletal muscle pump are illustrated in the image below.

All of the following would cause an increase in blood pressure except ________. A)a decrease in arterial diameter B)an increase in arterial resistance C)sympathetic stimulation D)a decrease in cardiac output

D)a decrease in cardiac output All of the listed options would cause an increase in blood pressure except a decrease in cardiac output. Cardiac output (CO) is a product of heart rate (HR) and stroke volume (SV). It gives a rate of blood volume that enters the blood circuits. A decrease in CO then, would decrease blood pressure. An increase in arterial resistance impairs blood flow and raises blood pressure. A decrease in arterial diameter impairs blood flow and raises blood pressure. Sympathetic stimulation of smooth muscle in some blood vessels will trigger vasoconstriction, thus increasing resistance and raising blood pressure. Factors involved in blood pressure regulation by way of the baroreceptor reflex are illustrated in the image below.

Reactive hyperemia is ________. A)controlled by the somatic nervous system B)controlled by the autonomic nervous system C)a result of changes in metabolic rate (rather than blood flow) D)a result of changes in blood flow (rather than metabolic rate)

D)a result of changes in blood flow (rather than metabolic rate) Reactive hyperemia is a result of changes in blood flow (rather than metabolic rate). Any physical change that triggers decreased blood flow—such as edema, physical pressure, or any physical change that causes the occlusion or added increase in resistance to blood flow—can be a cause of reactive hyperemia. Following the primary stimulus, the arterioles will vasodilate (if the stimulus is decreased blood flow) or vasoconstrict (if the stimulus is increased blood flow). These events are controlled locally and are not dependent upon the autonomic nervous system. As well, the somatic nervous system does not innervate smooth muscles. The negative feedback events in reactive hyperemia are shown in the image below.

Arterial baroreceptors are located in the aorta and carotid arteries so that pressure (and flow) to the ________ can be closely monitored. A)brain and pulmonary circuit B)pulmonary circuit and lungs C)heart and lungs D)brain and systemic circuit

D)brain and systemic circuit Arterial baroreceptors are located in the aorta and carotid arteries so that pressure (and flow) to the brain and systemic circuit can be closely monitored. Blood flow is maintained under all circumstances to the central nervous system and through the aorta as an indicator of systemic circuit blood flow efficiency. Baroreceptors located in the carotid artery (carotid sinus) and the aortic arch wall are able to provide sensory information to the brain in order to monitor blood flow and blood pressure. This affords the opportunity to make any necessary adjustments to sustain mean arterial pressure (MAP) and proper blood flow and perfusion. Although pressure should be monitored throughout the body, the aorta and carotid arteries do not lead to the pulmonary circuit, lungs, or heart. The location of the aorta and carotid arterial baroreceptors are shown in the image below.

Calcium channel blockers bind to Ca2+ channel proteins in vascular smooth muscle and cause ________. A)dilation of vessels, raising blood pressure B)constriction of vessels, lowering blood pressure C)constriction of vessels, raising blood pressure D)dilation of vessels, lowering blood pressure

D)dilation of vessels, lowering blood pressure Calcium channel blockers bind to Ca2+ channel proteins in vascular smooth muscle and cause dilation of vessels, lowering blood pressure. Calcium ion influx into smooth muscle initiates constriction of blood vessels, which raises blood pressure. Therefore, calcium channel blockers are a good treatment for hypertension.

The organ that plays the greatest role in regulating blood pressure by altering blood volume is the ________. A)heart B)lung C)liver D)kidney

D)kidney The organ that plays the greatest role in regulating blood pressure by altering blood volume is the kidney. The kidneys play a vital role in the regulation of blood pressure by regulating blood volume through control of fluid volume conservation or solute excretion via urine volume (water). Additionally the kidneys regulate erythropoiesis via their monitoring of oxygen levels in the blood and production of renal erythropoetic factor, which stimulates erythrogenesis in bone marrow. Not only does this increase the number of circulating erythrocytes, it also affects the viscosity of the blood and thereby produces an effect on resistance and ultimately on blood pressure. Vasopressin (a.k.a. antidiuretic hormone) produced by the posterior pituitary gland promotes water conservation by the kidney, which can raise blood pressure, while its reduction then increases water output in urine and correspondingly decreases blood pressure. In the kidneys, a hormone known as renin is produced when blood pressure decreases. This hormone initiates a sequence of events that leads to systemic vasoconstriction and increased TPR (total peripheral resistance) and MAP (mean arterial pressure). Neither the liver, heart, nor lungs can alter blood volume.

The velocity of blood flow is ________ through the capillaries than the blood flow through the aorta because the overall cross-sectional area of all capillaries is ________ in comparison to the aorta. A)faster; larger B)the same; the same C)faster; smaller D)slower; larger

D)slower; larger The velocity of blood flow is slower through the capillaries than the blood flow through the aorta because the overall cross-sectional area of all capillaries is larger in comparison to the aorta. This inverse relationship between cross sectional area and blood flow velocity is illustrated in the figure below.

The lymphatic system contains ________. A)veins and arteries B)arteries only C)arterioles only D)veins and capillaries

D)veins and capillaries The lymphatic system contains veins and capillaries. One of the primary functions of the lymphatic system is to collect and redistribute interstitial fluid so that excessive fluids do not produce edema. As the primary sites for exchange of materials and fluids between the blood plasma and interstitial fluids, systemic capillaries play a major role in the amount of fluid reabsorbed into the blood and the amount of fluid left to be collected by lymphatic capillaries. Thus, the lymphatic vessels originate as capillaries and do not contain arteries or arterioles. Lymphatic veins merge to collect lymph, filter it through lymph nodes and ultimately drain lymph into the circulatory system. The lymphatic system is represented as the green vessels in the image below.

What effect did fluid administration have on Mio's heart rate and blood pressure during standing? Fluid administration caused an increase in Mio's heart rate while standing, but did not alter blood pressure. Fluid administration caused an increase in Mio's blood pressure while standing, but did not alter heart rate. Fluid administration caused a decrease in Mio's blood pressure while standing, but did not alter heart rate. Fluid administration caused a decrease in Mio's heart rate while standing, but did not alter blood pressure.

Fluid administration caused an increase in Mio's blood pressure while standing, but did not alter heart rate.

Which of the following inaccurately represents normal forces across capillary walls? Capillary hydrostatic pressure decreases from arteriole end to venous end. Interstitial fluid oncotic pressure is almost zero. At rest, net filtration occurs across capillary walls. Interstitial fluid hydrostatic pressure increases from arteriole end to venous end. Capillary oncotic pressure is due primarily to plasma proteins.

Interstitial fluid hydrostatic pressure increases from arteriole end to venous end.

Based on these test results, which of the following best explains the cause of Mio's dizziness? (If needed, use MedlinePlus to research these choices.) Autonomic peripheral neuropathy Neurally-mediated syncope Phobias or depression Labyrinthitis

Neurally-mediated syncope?

Despite the use of meclizine, Mio still experiences dizziness during periods of standing . In light of the actions of meclizine, should Mio still be taking this medication? Why? (If needed, use MedlinePlus to research these choices.) No. Mio's dizziness persists despite taking meclizine. No. Mio's hypotension persists despite taking meclizine. Yes. Meclizine is decreasing Mio's dizziness due to motion sickness. Yes. Meclizine is decreasing Mio's nausea due to motion sickness.

No. Mio's dizziness persists despite taking meclizine.

Due to their diameter, capillaries have the greatest individual resistance, while the arteriole networks have the greatest total resistance. True False

T

Predict, under normal circumstances, how the administration of 1500 mL of fluid should influence a person's blood pressure and heart rate? The additional fluid increases blood volume, which increases blood pressure. To compensate, the heart rate decreases via the baroreceptor reflex. The additional fluid increases blood volume, which decreases blood pressure. To compensate, the heart rate increases via the baroreceptor reflex. The additional fluid decreases blood volume, which decreases blood pressure. To compensate, the heart rate decreases via the baroreceptor reflex. The additional fluid decreases blood volume, which increases blood pressure. To compensate, the heart rate increases via the baroreceptor reflex.

The additional fluid increases blood volume, which increases blood pressure. To compensate, the heart rate decreases via the baroreceptor reflex.

The emergency department nurse records Mio's symptoms: Patient is dizzy and faint upon standing, but never in sitting or supine positions; palpitations, muscle weakness in the legs, feeling of falling. Dizziness has worsened over 6 weeks. Occupation: restaurant server. No history of smoking, alcohol or illicit drug use; no history of mental illness. Why does Mio's heart rate increase when blood pressure decreases during periods of standing? Standing stimulates increased parasympathetic nervous system to increase heart rate in order to increase blood perfusion to the brain. Standing causes an increase in venous return, which increases heart rate in order to increase blood perfusion to the brain. Gravity stimulates the heart to increase its rate in order to increase blood perfusion to the brain. The baroreceptor reflex is compensating for the drop in blood pressure in order to increase blood perfusion to the brain.

The baroreceptor reflex is compensating for the drop in blood pressure in order to increase blood perfusion to the brain.

During exercise, cardiac output may increase by more than 170 % to meet the body's increased O2 demands. This increase in cardiac output increases blood pressure. But the accompanying increase in arterial pressure is relatively small—only about 40 % . What limits this increase in blood pressure so that it doesn't reach dangerously high levels during exercise? Vasodilation causes arterial diameter to increase in the exercising skeletal muscle. Blood vessels shorten in the contracting skeletal muscles. Blood volume decreases due to sweating. Hematocrit decreases as more interstitial fluid enters the blood vessels

Vasodilation causes arterial diameter to increase in the exercising skeletal muscle.

The driving force for bulk flow is always __________. a concentration gradient liquid a pressure gradient gas

a pressure gradient

An increase in blood flow to tissues in response to increased metabolic activity is called myogenic response. hypoxia. ischemia. active hyperemia. reactive hyperemia.

active hyperemia.?

A decrease in blood pressure at the arterial baroreceptors would result in which of the following? vasodilation of arterioles a decrease in heart rate a decrease in cardiac output an increase in heart contractility

an increase in heart contractility

Stimulation of the adrenal medulla would result in which of the following? vasodilation of arteries a decrease in cardiac output a decrease in blood pressure an increase in heart rate and contractility

an increase in heart rate and contractility

In the circulatory system, the largest pressure drop occurs across which blood vessels? arteries capillaries venules arterioles veins

arterioles

Which type of vessel provides the greatest amount of resistance to blood flow? the aorta arterioles veins capillaries

arterioles

Which of the following acts to increase arteriolar radius? beta-2 adrenergic agonist alpha adrenergic agonists angiotensin II norepinephrine released from the axon terminals of sympathetic neurons

beta-2 adrenergic agonist

The total cross-sectional area is greatest in which blood vessels? arterioles venules capillaries veins arteries

capillaries

Where are the sensors for the arterial baroreceptor reflex located? The sympathetic and parasympathetic nervous systems cardiovascular centers in the medulla oblongata carotid sinus and aortic arch

carotid sinus and aortic arch

Heart failure can be a result of a problem with heart rate or a problem with stroke volume, or both. A problem with heart rate involves some trouble with the __________ and a problem with stroke volume can involve some problem with __________ or cardiac muscle contractility, or both. conduction system; blood volume heart valves; blood volume papillary muscle; blood volume conduction system; total peripheral resistance

conduction system; blood volume

If heart failure occurs and cardiac output decreases, mean arterial pressure will __________, unless total peripheral resistance increases to compensate; for it to increase there must be a large amount of __________. increase; vasoconstriction decrease; vasodilation increase; vasodilation decrease; vasoconstriction

decrease; vasoconstriction

Which of the following would cause vasodilation of arterioles? decreased activity of the parasympathetic nervous system increased activity of the parasympathetic nervous system increased activity of the sympathetic nervous system decreased activity of the sympathetic nervous system

decreased activity of the sympathetic nervous system

Glucose moves across continuous capillary walls by what mechanism? facilitated transcytosis primary active transport secondary active transport diffusion

diffusion

An abnormal increase in venous pressure in the peripheral (outside the heart) circulation can cause a disturbance of Starling's law of the capillaries, which can result in __________. myocardial ischemia edema heart attack dehydration

edema

Military snipers use their knowledge of the respiratory sinus arrhythmia to help them aim as accurately as possible. Just before shooting, they will __________, which __________ their heart rate and helps steady their hands. inspire; speeds expire; speeds inspire; slows expire; slows

expire; slows

During exercise, which of the following tissues receive less blood flow compared to resting conditions? gastrointestinal tract only brain only skin only heart only both gastrointestinal tract and skin

gastrointestinal tract only

In comparison to the systemic circuit, the pulmonary circuit transports deoxygenated blood. has lower resistance to blood flow. has an equal pressure gradient to drive blood flow. is under greater pressure. has lower blood flow.

has lower resistance to blood flow.

The term __________ refers to any change in the heart that reduces its ability to maintain an adequate cardiac output. heart failure heart block myocardial infarction myocardial ischemia

heart failure

Cardiac output equals __________ multiplied by __________. mean arterial pressure; stroke volume end systolic volume; end diastolic volume end diastolic volume; end systolic volume heart rate; stroke volume

heart rate; stroke volume

The mean circulatory filling pressure is the pressure in the blood vessels. If the heart totally stopped working, its average value would be 7 mm Hg. If normal mean arterial pressure is 90 mm Hg to 100 mm Hg, it can be stated that the __________ contributes most of the mean arterial pressure. Thus, blood pressure will drop in most cases of __________. No matter how much __________ attempts to increase, it cannot compensate for this problem. heart; heart failure; total peripheral resistance heart rate; heart failure; total peripheral resistance blood vessel radius; significant systemic vasodilation; the heart stroke volume; heart failure; total peripheral resistance

heart; heart failure; total peripheral resistance

Which of the following is a decrease in tissue oxygen? hypoxia ischemia active hyperemia myogenic response reactive hyperemia

hypoxia

In response to a decrease in the stretch of a baroreceptor, sympathetic nervous activity will ________ while parasympathetic nervous activity will ________. not change : increase decrease : increase not change : remain constant increase : decrease decrease : remain constant

increase : decrease

Blood pooling occurs when blood accumulates in lower veins of the body due to the very high compliance of veins. Which of the following is NOT a result of blood pooling? increase in cardiac output reduction in arterial pressure decrease in venous return orthostatic hypotension

increase in cardiac output

If blood pressure is increased at the arterial baroreceptors, what would happen with the activity level of the parasympathetic nervous system (PNS) and sympathetic nervous system (SNS)? increased PNS and SNS activity decreased PNS activity and increased SNS activity increased PNS activity and decreased SNS activity

increased PNS activity and decreased SNS activity

Total peripheral resistance __________. increases as blood viscosity increases decreases with increasing length of the blood vessel is not a major factor in blood pressure in healthy individuals .increases as blood vessel diameter increases

increases as blood viscosity increases?

If the left ventricle undergoes failure, the blood will eventually back up into the pulmonary circulation; this raises pulmonary vascular pressure. Since blood from the right side of the heart (right atrium and right ventricle) must ultimately exit the heart through the left side of the heart, __________ can lead to __________. right-sided heart failure; left-sided heart failure right-sided heart failure; increased pulmonary vascular pressure left-sided heart failure; right-sided heart failure left-sided heart failure; systemic hypertension

left-sided heart failure; right-sided heart failure

The heart's purpose is to act as a pump that forcibly propels blood into the pulmonary and systemic circulations. It is the major factor in maintaining a proper mean arterial pressure in the systemic and pulmonary circulations. The formula that relates pressure gradients to resistance in the systemic circulation is __________. heart rate multiplied by stroke volume systolic pressure minus diastolic pressure end diastolic volume minus end systolic volume (SV = EDV - ESV) mean arterial pressure equals cardiac output multiplied by total peripheral resistance (MAP = CO x TPR)

mean arterial pressure equals cardiac output multiplied by total peripheral resistance (MAP = CO x TPR)

Which of the following chemical's concentration is NOT increased by an elevation in metabolic activity? oxygen pyruvic acid potassium hydrogen carbon dioxide

oxygen

Loss of plasma proteins will affect which of the pressures associated with capillary function? interstitial oncotic pressure plasma oncotic pressure plasma hydrostatic pressure interstitial fluid hydrostatic pressure

plasma oncotic pressure

The elastic nature of the largest artery's walls allows them to act as a ________, maintaining the driving force for blood flow while the heart is relaxed during diastole. contractile force pressure reservoir non-compliant structure non-distensible structure volume reservoir

pressure reservoir

An increase in blood flow to tissues in response to a previous reduction in blood flow is called hypoxia. ischemia. active hyperemia. myogenic response. reactive hyperemia

reactive hyperemia

Any change in the relative distribution of cardiac output to an organ is typically due to changes in which of the following? viscosity of the blood moving through that organ's vascular bed central venous pressure compliance of that organ's vascular bed mean arterial pressure resistance of that organ's vascular bed

resistance of that organ's vascular bed

Angiotensin II has what effect on systemic arterioles? vasospasm vasoconstriction and vasospasm neither vasodilation or vasoconstriction, but may cause vasospasm vasoconstriction vasodilation

vasoconstriction

Oxygen has what effect on systemic arterioles? vasospasm neither vasodilation or vasoconstriction, but may cause vasospasm vasoconstriction and vasospasm vasodilation vasoconstriction

vasoconstriction?

Nitric oxide has what effect on systemic arterioles? vasoconstriction and vasospasm vasoconstriction vasodilation neither vasodilation or vasoconstriction, but may cause vasospasm vasospasm

vasodilation

Which of the following is NOT a component of the microcirculation? arterioles veins venules metarterioles capillaries

veins

If the right ventricle undergoes failure, the blood will ultimately back up into superior and inferior vena cavae, thus raising __________ in the systemic circulation. venous pressure arterial pressure mean arterial pressure pulmonary vasculature pressure

venous pressure

When the heart pumps properly, it moves blood in such a manner that systemic __________ stays appropriately low and systemic __________ remains at its proper higher level. arterial pressure; venous pressure mean arterial pressure; central venous pressure barometric pressure; tidal volume pressure venous pressure; arterial pressure

venous pressure; arterial pressure

Veins functions as ________ reservoirs due to their ________ compliance. volume : high pressure : low volume : low pressure : lack of pressure : high

volume : high