Cardiovascular system - Pressure Applied and Blood pressure and its control

Why is blood pressure stated in units of "mm Hg"? Because... A. the first barometers operated with mercury. B. standard International (SI) units are not required in human biology. C. the haemoglobin molecule contains an atom of mercury. D. blood pressure is a length

Answer is A: Mercury (also known as hydrogyrum) was the liquid used in manometers (pressure measuring devices) because of its very high density compared with water

What is "systolic pressure"? A. The peak pressure in the blood due to contraction of the left ventricle B. The minimum pressure in the blood prior to contraction of the left ventricle C. It may be obtained by multiplying cardiac output by total peripheral resistance. D. It is also known as mean arterial pressure

Answer is A: Systole means "contraction" in Greek. So systolic pressure is the pressure produced by the contraction of the left ventricle. Choice C refers to mean arterial pressure, which is less than systolic pressure

Which statement about cardiac output is correct? Cardiac output is: A. the sum of volume of blood pumped by left and right ventricles per minute. B. the mean arterial pressure divided by total peripheral resistance C. the mean arterial pressure multiplied by stroke volume. D. the blood volume multiplied by heart rate

Answer is B: MAP= CO×TPR, so CO = MAP÷TPR

A rise in arterial blood pressure stretches the vessel walls which contain baro-receptors. Which of the following responses does this produce? The barorecep-tors send a: A. slower stream of impulses to the vasomotor centre which inhibits it. B. faster stream of impulses to the vasomotor centre which inhibits it. C. slower stream of impulses to the vasomotor centre which stimulates it. D. faster stream of impulses to the vasomotor centre which stimulates it

Answer is B: When a blood vessel wall is stretched it stimulates baroreceptors to increase their stream of impulses to the vasomotor centre which inhibits it. This means the smooth muscle in blood vessel walls will relax and the vessel diameter will increase and so BP is reduced

Which three factors affect blood pressure? A. heart rate, stroke volume and total peripheral resistance. B. cardiac output, heart rate and pulse pressure. C. total peripheral resistance, cardiac output and blood volume. D. diastolic pressure, systolic pressure and pulse pressure

Answer is C: Blood pressure rises and falls as blood volume rises and falls. If volume does not change, then just cardiac output and total peripheral resistance determine BP. Choice A is correct for a constant blood volume

When blood pressure is measured in the brachial artery by the auscultatory method, why should the arm be at the same level as the heart? A. if the arm is lower than the heart, brachial artery pressure will be lower as blood flow is assisted by gravity. B. if the arm is higher than the heart, brachial artery pressure will be higher as more force is required to pump blood up hill. C. to avoid any hydrostatic pressure effects on the brachial artery pressure. D. there is no reason for it, the practice is part of "nursing ritual".

Answer is C: If the arm is higher, the pressure in the brachial artery will be lower than aortic pressure (and vice versa)

The Korotkoff sounds that are listened for during a blood pressure measure-ment by the auscultatory method are caused by: A. turbulent blood flow in the aorta B. the difference between systolic pressure and cuff pressure. C. turbulent flow in the collapsed brachial artery D. the opening and closing of the heart valves

Answer is C: Squashing the brachial artery will cause blood flow to be turbu-lent as it passes through the constriction. This turbulence creates sound that can be detected with a stethoscope.

Blood may flow in the aorta with a speed of 30 cm/s and in the capillaries with a speed of only 0.1 m/s. Why is there such a large difference in speed? A. the capillaries are much further from the heart than the aorta. B. the very narrow capillaries present a large resistance to blood flow com-pared to the large diameter aorta. C. the total cross-sectional area of the lumens of the capillaries is much greater than the cross-sectional area of the aorta. D. the length of the aorta is short compared to the length of a capillar

Answer is C: The "equation of continuity" may be stated: volume flow rate = cross-sectional area × speed of flow. Hence if the total cross-sectional area of capillaries is very large (as it is), the speed of flow can be very slow while still allowing the required volume flow rate

Why is the blood pressure in the pulmonary arteries less than in the aorta? A. the expansion and contraction of the lungs pumps blood through its blood vessels. B. blood flowing to the lungs does not need to overcome gravity. C. pulmonary resistance is greater than the peripheral resistance. D. pulmonary resistance is less than peripheral resistance

Answer is D: As pulmonary resistance is much lower than systemic resistance, the BP required to overcome it is much less too. Hence heh right ventricle does not need to produce the high pressure of the left ventricle to move blood through the pulmonary circuit.

What is "autoregulation"? It is the adjustment of blood flow to each tissue due to: A. hormonal control B. neural control C. systemic factors D. local factors

Answer is D: Autoregulation refers to the tissue regulating its own blood flow depending on the concentration of chemicals (oxygen, carbon dioxide, metabo-lites) within the tissue

In which of the following situations would blood pressure be increased? A. antidiuretic hormone (ADH) secretion is inhibited. B. the kidneys absorb less water before it is excreted as urine. C. the extracellular fluid volume decreases. D. the extracellular fluid volume increases

Answer is D: Extracellular volume includes the blood. If its volume increases, that means blood volume increases and this will increase BP.

In the circulatory system, why does an increase in cardiac output cause an increase in volume flow rate (of blood)? Because: A. an increased cardiac output causes vasoconstriction. B. as cardiac output increases so blood viscosity increases. C. as cardiac output increases, the resistance of the systemic circulation to blood flow decreases. D. cardiac output and volume flow rate are the same thing

Answer is D: The number of millilitres of blood per minute is volume flow rate and cardiac output. They are the same thing.

What does administering Beta-Blocking medication do? A. It targets adrenergic neurotransmission to Beta receptors B. It targets cholinergic neurotransmission to decrease blood pressure C. It acts principally upon Beta 2 and Alpha 1 receptors D. It exposes the Beta 1 receptors to enhance neurotransmission

Answer is A: "Beta-blockers" block beta-1 receptors. These receptors are "adrenergic" as they bind adrenaline (& noradrenaline). Blocking them dimin-ishes neurotransmission.

Which of the following readings (in mm Hg) would be considered within a healthy resting blood pressure range? A. 115/70 B. 120/30 C. 100/90 D. 145/90

Answer is A: A reading above 140/90 is considered hypertensive. A diastolic reading of 30 is too low; a systolic reading of 100 is low-ish; a systolic reading of 145 is too high

One of the following is a vasodilator. Which one? A. atrial natriuretic peptide (ANP). B. angiotensin II. C. epinephrine (adrenaline). D. an increase in sympathetic impulses.

Answer is A: ANP causes a decrease in BP and vasodilation is one of the ways by which this is achieved

A resting blood pressure stated as 120/80 (in units of mmHg) refers to A. maximum pressure in the aorta/minimum pressure in the aorta B. maximum pressure in the aorta/maximum pressure in the vena cavae C. diastolic pressure/systolic pressure D. left ventricular systolic/right ventricular systolic

Answer is A: Arterial blood pressure cycles between a maximum value and a minimum value in time with the heartbeat. It is recorded as the maximum value adjacent to the minimum value

Say a diastolic blood pressure reading was 80 mm Hg. This is consistent with which one of the following statements? A. the diastolic reading is 80 mm Hg greater than atmospheric pressure. B. pressure is measured in length units. C. the diastolic reading is 80 mm Hg less than atmospheric pressure. D. this is the maximum pressure produced by contraction of the myocardium

Answer is A: Because atmospheric pressure (about 760 mmHg) is always pres-ent, it is taken to be a "relative zero" and other pressures are stated as an amount greater than atmospheric pressure. We say 80 implying 80 more than 760, rather than stating 840 mmHg (760 + 80)

What is one of the determinants of the resistance to blood flow? A. blood viscosity. B. cardiac output. C. heart rate. D. the blood osmolarit

Answer is A: Blood viscosity, largely determined by the concentration of rbc (the haematocrit) affects blood's resistance to flow

What units is a blood pressure of 120/80 is expressed in? A. Millimetres of mercury B. Centimetres of blood C. Centimetres of mercury D. Pascals

Answer is A: Despite the mmHg not being an SI unit, blood pressure is still commonly reported in this unit

If a person has an arterial blood pressure measurement of 16 kPa (120 mmHg), this equates to which of the following pressures in newtons per square centimetre? A. 16,000 B. 160 C. 1.6 D. 1600

Answer is A: The "newton per square metre" is renamed the pascal. 1 N/m2 = 1 Pa. 16,000 N/m2 = 16,000 Pa = 16 kPa

By which means will the sympathetic response raise blood pressure? A. Vasoconstriction due to stimulation of alpha receptors B. Vasoconstriction due to stimulation of beta receptors C. Increase cardiac output due to stimulation of alpha receptors D. Increased stroke volume due to stimulation of alpha receptors

Answer is A: The neurotransmitter epinephrine will attach to the alpha receptor sites of smooth muscle in blood vessels and cause vasoconstriction (except for blood vessel in skeletal muscle). Choices C and D are wrong as beta, not alpha receptors increase CO. Choice A is wrong as alpha (not beta) produce vasoconstriction.

Which of the following statements about the cardiovascular control centre of the brain is FALSE? A. increased impulses along parasympathetic fibres causes vasoconstriction. B. increased output along the sympathetic fibres INcrease heart rate. C. output along of the parasympathetic fibres DEcreases heart rate. D. decreased output along the sympathetic fibres causes dilation of arterioles.

Answer is A: The parasympathetic system does not have a role in vasoconstric-tion or vasodilation.

Which of the following is NOT true about turbulent blood flow? A. turbulent flows exists when blood is flowing in smooth streamlines. B. it may occur when blood passes through a constriction or stenosis. C. it occurs if blood speed is high. D. turbulent flow is noisy

Answer is A: When blood flows in smooth streamlines parallel to the vessel walls, it is known as streamline flow. In turbulent flow the liquid moves in eddies and will not always be parallel to the vessel walls

Consider an arteriole that is 50 cm distant from the aorta. If blood pressure in the aorta is 130 mmHg and in the arteriole is 30 mmHg, what is the pressure GRADIENT between the two? A. 2 mmHg/cm B. 30 mmHg/cm C. 100 mmHg/cm D. 130 mmHg/cm

Answer is A: pressure gradient = pressure drop / distance = (130 - 30) / 50 = 2mmHg/cm

Blood flow is largely regulated at a tissue level. Which of the following could be said regarding this process? A. A rise in the blood level of O2 will result in vasodilation B. A raised CO2 level results in vasodilation C. Acidaemia directly increases vasopressin (ADH) release D. A raised CO2 blood level will result in an increased serum alkalinit

Answer is B: A high level of CO2 in the tissues will promote vasodilation to remove it, and to provide more O2. ADH produces vasoconstriction which is the opposite of what is required to correct acidaemia. Normally (in the absence of ventilation problems) the blood buffers prevent any change in blood pH so choice D is wrong

An increase in which of the following would NOT produce an increase in car-diac output? A. heart stroke volume B. heart rate C. peripheral resistance D. venous return

Answer is C: Increasing peripheral resistance would not increase CO unless there was a compensating increase in BP

The definition of mean arterial pressure (MAP) may be written as: A. MAP = stroke volume × heart rate B. MAP = (diastolic pressure + systolic pressure) ÷ 2 C. MAP = cardiac output × peripheral resistance D. MAP = diastolic pressure + pulse pressure

Answer is C: Mean arterial pressure, MAP = CO × TPR. MAP also is diastolic pressure +1/3× pulse pressure

What is the pressure gradient produced by the left ventricle equal to? A. the mean arterial pressure. B. the difference between mean arterial pressure and pressure at the start of the capillaries. C. the difference between mean arterial pressure and pressure at the start of the capillaries, divided by the distance between the start of the aorta and capillaries. D. the mean arterial pressure divided by the distance between the start of the aorta and capillaries

Answer is C: Pressure gradient between two points is the pressure difference between two points, divided by their distance apart.

When a person is standing upright, what can be said about the arterial blood pressure in their feet? A. It will be greater than arterial pressure in the aorta. B. It will be less than the arterial pressure in the aorta. C. It will be the same as the arterial pressure in the aorta. D. It will be the same as the venous blood pressure in the feet

Answer is A: Due to the head of liquid above the feet contributing hydrostatic to the arterial pressure produced by the heart, arterial blood pressure in the feet will be greater than in the aorta

One of the following does NOT contribute to peripheral resistance. Which one? A. heart rate. B. blood viscosity. C. diameter of blood vessels. D. length of blood vessels

Answer is A: Heart rate contributes to cardiac output but not peripheral resistance.

Which statement regarding the regulation of blood pressure by the endocrine system is correct? A. In comparison to other physiological regulatory processes, it is slow. B. Aldosterone is responsible for the conversion of angiotensin I into angioten-sin II C. In response to a drop in blood pressure, the renin-angiotensin aldosterone system leads to parasympathetic stimulation D. Angiotensin converting enzyme (ACE) is responsible for converting angio-tensinogen into angiotensin I

Answer is A: Hormone control mechanisms are slower than those controlled by the nervous system. ACE converts angiotensin I to angiotensin II. Parasympathetic stimulation decreases CO and hence BP

If dietary salt intake is excessive, which of the following will NOT occur? A. Less ADH will be secreted B. The osmolarity of extracellular fluids will increase C. The thirst centre will be stimulated D. The extracellular fluid volume increases

Answer is A: If a greater than recommended amount of salt is in the diet, moreADH will be secreted so that additional water is reclaimed from the nephron filtrate. This will tend to decrease blood osmolarity. Hence it will not occur that "less ADH will be secreted".

Which completed statement is NOT true? Peripheral resistance: A. increases if diameter of blood vessels increases B. is greater if the total length of blood vessels is greater C. increases if viscosity of blood increases D. is greater than pulmonary resistance

Answer is A: If the diameter of blood vessels increases, there will be less fric-tion with the vessel wall and peripheral resistance will decrease.

Which situation below would make the heart beat faster? A. an increase in sympathetic impulses along the cardioaccelerator nerves B. an increase in parasympathetic impulses along the cardioaccelerator nerves C. an increase in sympathetic impulses along the vagus nerves D. an increase in parasympathetic impulses along the vagus nerves

Answer is A: Increased sympathetic stimulation cause an increase in heart rate. The vagus nerve carries only parasympathetic impulses

Which of the following is most unlikely to increase blood viscosity? A. leucocytosis B. dehydration C. hypothermia D. an infusion of packed red blood cells

Answer is A: Leucocytosis is an increase in the number of wbc above the nor-mal range. Such a rise would have a minimal effect on viscosity as viscosity is due largely to the number of the much more numerous rbc in normal blood

As a result of the pumping action of the heart, we are able to feel pulsations in our superficial arteries (e.g. the radial pulse). This effect is an example of which of the following? A. Pascal's principle. B. Torricelli's law. C. The Bernoulli effect. D. Starling's law of the heart.

Answer is A: Pascal's states that pressure applied to an enclosed fluid is trans-mitted undiminished throughout the fluid. The LV pushes blood into the aorta at pressure. This pressure distends the artery walls of the brachial artery - even though it is 70 cm away from the heart - and we can feel the pulsations as pres-sure rises and falls

If a stenosis reduces the size of a blood vessel to half of the original diameter, the volume flow rate through the vessel will be reduced. Which relationship below determines the extent of the decrease in flow? A. Poiseuille's law. B. Bernoulli's theorem C. Dalton's law. D. Pascal's principle

Answer is A: Poiseuille's law relates diameter (radius) of blood vessel to vol-ume flow rate.

Which three hormones have a role in regulating blood pressure? A. angiotensin II, ADH and ANP B. renin, angiotensin II and ADH C. vasopressin, ADH and ANP D. angiotensin II, ACE and ADH

Answer is A: Renin is an enzyme that coverts angiotensinogen into angiotensin I, while ACE is an enzyme that converts angiotensin I into angiotensin II. Vasopressin and ADH are the same hormone

Consider Pascal's principle. If the heart exerts a pressure of 120 mmHg on the blood in the aorta, where else in the body will the blood pressure be 120 mm Hg? A. in the brachial artery of a seated person B. in the superior vena cava of a standing person. C. in the capillaries of the feet of a supine person D. in the anterior tibial artery of a person who is standing

Answer is A: Resting BP is usually measured while the subject is seated. In this posture, the brachial artery is at the level of the heart. Hence gravity will not affect the BP in the brachial artery. In a standing person, gravity would increase the BP in the legs. BP in the capillaries and vena cava is not comparable to BP in the aorta.

Too much salt (sodium chloride) in the diet increases blood osmolarity and can cause increased arterial blood pressure. Which of the following is NOT a way that salt affects blood pressure? A. Salt causes peripheral vasoconstriction. B. Salt stimulates thirst. C. Salt stimulates ADH secretion. D. Salt causes fluid shift from the intracellular fluid to the extracellular fluid

Answer is A: Sodium chloride does not cause peripheral vasoconstriction

Which of the following will increase cardiac output? A. an increase in sympathetic impulses B. an increase in parasympathetic impulses C. a faster stream of impulses from the baroreceptors D. an increase in vasodilation

Answer is A: Sympathetic impulses will increase CO. Increased baroreceptor activity would decrease CO.

Which of the following would cause a rise in mean arterial blood pressure? A. sympathetic impulses along the cardio-accelerator nerves. B. changing from a standing position to a supine position. C. generalized vasodilation of blood vessels. D. a severe haemorrhage.

Answer is A: Sympathetic stimulation increases heart rate and contractility which increases cardiac output which increases BP. The term cardio- accelerator nerve should provide a clue

120/80 is recorded as a blood pressure measurement. What does this mean? A. systolic pressure is 120 and diastolic pressure is 80. B. left ventricular systolic pressure is 120 and left ventricular diastolic pressure is 80. C. the average of the left and right ventricular systolic pressure is 120 and the average of the left and right ventricular diastolic pressure is 80. D. left ventricular diastolic pressure is 120 and left ventricular systolic pres-sure is 80.

Answer is B: Although not always specifically stated, a blood pressure of 120/80 refers to the BP in the aorta, that is, caused by the left ventricle. Hence choice A is not as good an answer as choice B.

What does Angiotensin II do? A. It is a weak vasoconstrictor and requires activation by Angiotensinogen B. It acts via several mechanisms that cause blood pressure to increase C. It reduces blood pressure through decreasing vascular smooth muscle tone D. It causes an increase in urine output by triggering ADH release

Answer is B: Angiotensin II is a vasoconstrictor. It also stimulates thirst, the secretion of ADH and the adrenal glands to secrete aldosterone. All of which cause BP to increase (provided that we do drink)

What is the role of angiotensin II? To: A. decrease blood pressure by promoting vasodilation of veins. B. increase blood pressure by promoting vasoconstriction of arterioles C. decrease blood pressure by promoting excretion of water in urine. D. increases blood pressure by promoting absorption of Na+.

Answer is B: Angiotensin II promotes vasoconstriction which increases periph-eral resistance which increases BP. It also stimulates the adrenal glands to pro-duce aldosterone. It is aldosterone that causes an increase in Na+ absorption, hence choice B is a better answer than D

The antihypertensive drugs known as "ACE inhibitors" function by doing which of the following? A. preventing the release of ADH B. blocking the formation of angiotensin II C. blocking the release of renin D. preventing the entry of Ca++ to vascular smooth muscle.

Answer is B: Angiotensin converting enzyme is known as "ACE". An ACE inhibitor will prevent this enzyme from converting angiotensin I into angioten-sin II. Hence the blood pressure raising effects of angiotensin II will be prevented

What is the consequence when ADH is released? A. blood osmolarity increases B. the permeability of the collecting ducts to water is increased C. peripheral vasodilation increases D. blood pressure decreases

Answer is B: Anti-diuretic hormone decreases the volume of urine formed by causing water to be reclaimed from the DCT and collecting duct. Hence blood osmolarity will not increase and BP will not decrease

Which hormone produces a decrease in arterial blood pressure? A. vasopressin B. ANP C. ADH D. angiotensin II

Answer is B: Atrial natriuretic enzyme (ANP) exerts effects that result in a decrease in BP

Consider a capillary where the blood hydrostatic pressure is 3300 Pa at the arterial end and 2000 Pa at the venous end. If the difference between the osmotic pressures inside and outside the capillary is 2900 Pa, what would be the net pressure difference between the surrounding tissue and blood in the venous end of the capillary? A. 400 Pa. B. 900 Pa. C. 1300 Pa. D. 4900 Pa

Answer is B: Blood hydrostatic pressure tends to move water and solutes out of the capillary, while osmotic pressure tends to move water into the capillary. Taking the outward direction as positive: net pressure at the venous end is = 2000 − 2900 = −900 Pa and so is directed into the capillary

To what does the term "cardiac output" refer? A. the speed of blood flow through the aorta. B. the volume of blood flowing through the aorta per minute. C. the volume of blood pumped by the heart with each beat. D. the number of heart beats per minute.

Answer is B: CO is the volume flow rate. The volume of blood pumped per minute. Choice C is the stroke volume. Choice D is the heart rate.

Which of the following statements about the cardiovascular control centre of the brain is TRUE? A. increased impulses along parasympathetic fibres causes vasoconstriction. B. output along the sympathetic fibres INcrease heart rate. C. output along the parasympathetic fibres INcrease heart rate. D. output along the sympathetic fibres DEcrease heart rate

Answer is B: Impulses travelling in the sympathetic fibres increases heart rate (in preparation for increased physical activity

What would be the effect produced if the cardiovascular centre increased the rate of parasympathetic impulses it sends out? A. heart rate would increase B. heart rate would decrease C. vasoconstriction of blood vessels would increase D. vasodilation of blood vessels would increase

Answer is B: Increased parasympathetic causes a decreased heart rate. Vasoconstriction and vasodilation are controlled by the sympathetic division not the parasympathetic.

Which will produce a decrease in arterial blood pressure? A. vasoconstriction. B. increased parasympathetic stimulation. C. increased blood osmolarity. D. increased cardiac output

Answer is B: Increased parasympathetic stimulation will decrease heart rate and myocardial contractility. This will cause CO and hence BP to decline

What does the term "systolic pressure" refer to? A. the value, in mmHg, that appears in the denominator of a blood pressure measurement B. the peak pressure in the blood due to the contraction of the left ventricle. C. the minimum pressure in the aorta prior to left ventricular contraction D. the difference between maximum and minimum arterial blood pressures

Answer is B: It is the maximum pressure produced by the LV during contrac-tion (while the body is at rest).

Which of the following statements about the cardiovascular centre of the brain is FALSE? A. it consists of the cardiac centre and the vasomotor centre. B. output along fibres of the sympathetic nervous system DEcrease heart rate. C. output along fibres of the parasympathetic nervous system DEcrease heart rate. D. output along fibres of the sympathetic nervous system INcrease heart rate

Answer is B: Output along fibres of the sympathetic nervous system actually increases heart rate. So choice B is FALSE and answers the question that was asked.

An increase in parasympathetic impulses along the vagus nerve causes A. dilation of the arterioles B. a decrease in blood pressure C. an increase in vasoconstriction D. increases the force of myocardial contraction

Answer is B: Parasympathetic stimulation causes a decrease in BP as heart rate and force of contraction are decreased. Dilation and constriction of blood ves-sels are controlled by the sympathetic nervous system

Due to an atheromatous plaque, a man's coronary artery has narrowed to one third of its healthy diameter, all other things being equal, his blood flow rate (ml/min) in that artery would A. be one third of the unobstructed value B. be one eighty-first of its healthy value C. be one ninth of its healthy value D. be one twenty-seventh of its healthy value

Answer is B: Poiseuille's law states that volume flow rate is proportional to radius to the fourth power, so blood flow rate would be 1/3*1/3*1/3*1/3=1/81

If the blood pressure at the arterial end of a blood capillary is 4000 Pa (30 mmHg) and at the venule end of the capillary is 2000 Pa (15 mmHg), and the capillary has a length of 1 mm, what will the pressure gradient in the capillary be? A. 4000 Pa/mm B. 2000 Pa/mm C. 15 mmHg D. 45 mmH

Answer is B: Pressure gradient = (pressure difference)/ length==(4000-2000)/1=2000Pa/ mm. Choice C states the pressure difference but not the gradient

When blood pressure drops, which of the following responses would happen? A. atrial natriuretic peptide is released from the heart B. the kidneys release renin which catalyses the formation of angiotensin I C. the rate of sodium excretion by the kidneys increases D. the secretion of anti-diuretic hormone is inhibited

Answer is B: Renin acts on angiotensinogen and eventually angiotensin II would be formed. Angiotensin has four effects that will cause BP to rise.

During an auscultatory blood pressure determination, the Korotkoff sounds that are listened for are produced because A. the partial pressure of the blood has been increased. B. the blood flow is turbulent. C. of the viscosity of the blood. D. the volume flow rate has decreased

Answer is B: Turbulent blood flow produces sound that is audible with a stetho-scope. Auscultatory systolic BP measurement requires the artery to be squashed flat. At the point just before blood flow is stopped the blood squirts through the squashed artery in a turbulent fashion and this noisy squirting blood produces a sound audible with a stethoscope.

In a resting heart pumping 5 litres of blood per minute, the average aortic blood pressure is 13.3 kPa. Suppose arterial blood pressure falls to 3.3 kPa at the start of a capillary that is 50 cm from the heart. What is the pressure gradient along the path from heart to capillary? A. 5 l/min. B. 200 Pa/cm. C. 2000 Pa/m. D. 10,000 Pa

Answer is B: pressure gradient = pressure drop + distance = (13300 - 3300) / 50 = 200 Pa /cm. Choices A and D are not gradients

Which of the following events would you expect to observe in response to a drop in a patients' blood pressure? A. Renin is converted to Angiotensinogen B. Angiotensin 2 is converted into Aldosterone C. ADH (Anti Diuretic Hormone) will be released by the posterior pituitary gland D. Baroreceptors signal the SA node to slow

Answer is C: ADH causes more water to be reclaimed from the urine filtrate. This return of water to the blood volume prevents it from decreasing. Maintain blood volume is a way of preventing BP from falling further

Complete the following sentence. When standing, the arterial blood pressure in the feet is: A. less than the arterial blood pressure of the hands. B. reduced due to the action of valves in supporting the blood in the veins of the legs. C. increased by the hydrostatic pressure due to the "head of blood" in the vessels. D. less than the venous blood pressure in the feet

Answer is C: Because of gravity, the position of the body in space affects blood pressure. When standing, hydrostatic pressure increases the BP in the blood vessels of the feet.

Given that a healthy resting blood pressure may be stated as 16/10.6 (in units of kPa). What would the reading on the pressure gauge of a sphygmomanometer that was measuring blood pressure in the posterior tibial artery of a standing patient be closest to? A. 6 kPa, the average blood pressure at the arterial end of the capillaries. B. 12 kPa, the hydrostatic pressure due to head of blood. C. 28 kPa, the hydrostatic pressure plus average aortic pressure. D. 107 kPa, atmospheric pressure plus average pressure at the start of the capillaries

Answer is C: Both pressure due to the head of liquid between the heart and the feet (about 11 kPa) and pressure due to the pumping action of the heart (16 kPa) must be added to arrive at BP in the feet when standing. Alternatively, the value in choice D is too high, and choices A and B are values that are too low and do not take into account the two components that are operating in a standing person.

Which statement about cardiac output is correct? A. cardiac output is peripheral resistance multiplied by stroke volume. B. mean arterial pressure multiplied by peripheral resistance is cardiac output. C. cardiac output is heart rate multiplied by stroke volume. D. cardiac output is blood volume multiplied by heart rate

Answer is C: Cardiac output (in ml per minute) = stroke volume (in ml per beat) times heart rate (in beta per minute).

Which of the following is a class of antihypertensive medication which specifi-cally target a reduction in blood volume? A. Beta blockers B. Calcium Channel Blockers C. Diuretics D. Anticoagulants

Answer is C: Diuretics promote the production of urine - which is filtered from blood. Hence blood volume decreases as more urine is produced

An intravenous (IV) infusion flows into a vein because of hydrostatic pressure. This depends LEAST on which of the following? A. gravity B. the density of the IV solution C. the volume of liquid in the IV bag D. the "head" of liquid

Answer is C: Gravity acting on the head of liquid provides the pressure that forces an IV solution into a vein. As long as the head of liquid is maintained, the volume contained in the IV bag has little influence.

Which of the following is the best definition of hypertension? A. a systolic pressure of more than 140 mmHg and a diastolic pressure of more than 90 mmHg B. a diastolic pressure of more than 140 mmHg and a systolic pressure of more than 90 mmHg C. a blood pressure of more than 140/90 mmHg measured after 5 minutes of inactivity D. a blood pressure of less than 110/70 mmHg measured after 5 minutes of inactivity

Answer is C: Hypertension refers to a resting BP of more than 140/90. Choice A is correct except that there is no reference to being "at rest"

If mean arterial pressure is kept constant while a small artery changes its radius from 1 mm to 2 mm, what will happen? A. blood volume flow rate through the artery will double. B. blood volume flow rate through the artery will increase to four times its previous value. C. blood volume flow rate through the artery will be sixteen times the original value. D. blood speed will halve so there will be no change in volume flow rate

Answer is C: If an artery dilates to twice its previous value, sixteen times (24) as much blood will flow per minute

When the AV valve between the left atrium and left ventricle is open, the blood pressure in both chambers is zero. When the left ventricle contracts the AV valve shuts and blood pressure in the left ventricle rises while blood pressure in the left atrium reaches and stays at ~5 mmHg. Blood pressure in the aorta is ~80 mmHg at the end of diastole. Which of the following will happen next? A. When blood pressure in the left ventricle reaches 6 mmHg, blood will flow into the left atrium. B. When blood pressure in the left ventricle reaches 80 mmHg, blood will flow into the aorta C. When blood pressure in the left ventricle reaches 81 mmHg, blood will flow into the aorta. D. Blood volume in the left ventricle will decrease as pressure increases until there is sufficient pressure to push blood into the aort

Answer is C: Pressure in the LV will rise as the myocardium contracts until pressure in the LV is greater than the pressure in the aorta. When this happens, the aortic valve will be forced open and blood will move from the LV into the aorta through the aortic valve.

Which of the following statements regarding antihypertensive medication is correct? A. Calcium channel blockers are a class of drug used to reverse a decrease in blood volume. B. Diuretic medication principally affects peripheral resistance. C. Beta blockers target cardiac sympathetic innervation. D. ACE inhibitors promote the effects of the renin-angiotensin aldosterone system

Answer is C: The neurotransmitters epinephrine & norepinephrine attach to the beta-1 receptor sites of the heart and cause HR & contractility to increase. This sympathetic stimulation promotes an increase in CO (and hence BP). Blocking (preventing the binding of E and NE) their effect prevents sympathetic stimulation.

What are the receptors that are sensitive to blood pressure called? A. pacinian corpuscles B. nociceptors C. baroreceptors D. chemoreceptors

Answer is C: The prefix "baro"receptors refers to a barometer (an air pressure measuring device) where the unit one bar is the pressure of one standard atmosphere

A systolic blood pressure which is stated as 16 kPa (120 mmHg) means that the pressure in the arterial blood is: A. negative 16 kPa. B. 16 kPa above zero kilopascals. C. 16 kPa greater than atmospheric pressure. D. 16 kPa less than atmospheric pressure

Answer is C: The pressure exerted by the atmosphere is disregarded when read-ing the pressure on the gauge. 16 kPa actually means that blood is actually at a pressure of 16 + 101 kPa

When taking a subject's blood pressure you are actually measuring the differ-ence between total pressure and which other pressure? A. gauge pressure B. blood pressure C. atmospheric pressure D. standard atmospheric pressure

Answer is C: The pressure on the gauge used to measure blood pressure dis-plays the difference between atmospheric pressure and blood pressure. That is, total pressure is atmospheric pressure plus the reading on the gauge

Cardiac output does NOT depend on one of the following, which one? A. the rate of venous return to the heart B. the blood viscosity C. the volume flow rate through the circulatory system D. the pressure drop (between start of aorta and start of capillaries)

Answer is C: This is the required answer as CO is the same thing as volume flow rate

What may correctly be said about baroreceptors? A. They are located in the walls of the aortic arch and the inferior vena cava B. A drop in blood pressure triggers the baroreceptor reflex which causes vaso-dilation and an increased heart rate C. They promote vasoconstriction and an increased force of myocardial con-traction in the hypotensive patient D. They respond directly to alterations in circulating oxygen levels

Answer is C: Vasoconstriction and increased contractility promotes an increase in BP. Baroreceptors are located in the walls of the carotid sinus and aortic sinus, among other places. Choices B & D are wrong

Which one of the following will make blood pressure fall? A. increased cardiac output B. increased heart rate C. increased vasodilation D. increased peripheral resistance

Answer is C: Vasodilation decreases resistance to blood flow, which means the same CO can be maintained by a lower BP.

What will be the result of an increase in sympathetic impulses along the vaso-motor nerves? A. increased heart rate and force of contraction B. decreased heart rate and force of contraction C. generalised vasoconstriction D. generalised vasodilation

Answer is C: Vasomotor nerves should give the clue that vessels will be set in motion. An increase in impulses will result in vasoconstriction.

What effect will increasing the concentration of red cells in blood have? It will: A. decrease blood viscosity and increase aortic pressure B. increase blood viscosity and decrease aortic pressure C. increase blood viscosity and increase aortic pressure D. decrease blood viscosity and decrease aortic pressure

Answer is C: Viscosity will increase as the number of rbc increases. This will also increase the resistance to flow so BP in the aorta will increase a bit

A man who is standing has a resting systolic blood pressure of 120 mmHg at the start of his aorta. What will be the pressure in the arteries of his feet? A. about 40 mmHg, as arterial blood pressure decreases with distance from the heart. B. about 120 mmHg as arterial blood pressure does not fall appreciably until just before blood enters the capillaries. C. about 200 mmHg as the "head" of liquid increases the blood pressure in the feet. D. about 80 mmHg as blood pressure will drop in the absence of venous return when the "skeletal muscle pump" is not operatin

Answer is C: When standing, the BP in the feet results from the pumping of the heart (120 mmHg) as well as the hydrostatic effect of the head of liquid - another 80 mmHg or more

Suppose that a person who is standing still, has a mean arterial pressure in the aorta of 13 kPa (98 mmHg). The blood pressure at the start of the arterioles of the feet will be: A. about the same since healthy arteries present very little resistance to blood flow. B. less because blood pressure decreases along arteries as distance from the heart increases. C. more because of the hydrostatic pressure exerted by the column of blood in the arteries. D. less because of the decreased venous return which results from the person's inactivity.

Answer is C: When standing, the vertical column of blood in the arteries exerts pressure on the blood in the arterioles in the feet due to the head of liquid. Hence mean arterial BP in the feet will be considerably greater than 13 kPa

When arterial blood pressure is stated as 120/80, what do the numbers refer to? A. 120 ÷ 80 = 1.5 = mean arterial pressure B. pulse pressure/mean arterial pressure C. systolic pressure/diastolic pressure D. arterial pressure/venous pressur

Answer is C: Writing BP as 120/80 is an abbreviated way of writing systolic pressure of 120 mmHg and diastolic BP of 80 mmHg

According to Poiseuille's law of fluid flow, the volume flow rate, V, is propor-tional to radius to the fourth power. What would happen to the volume flow rate of blood if the diameter of an artery decreased to 20 % (1/5) of its original diameter? V would: A. be one fifth (0.2) of its original value. B. be one twenty-fifth (0.04) its original value. C. be 1/625 (0.0016) of its original value. D. five times its original value

Answer is C:(/)(.).15020 001644==. Narrowing of arteries has dire conse-quences for blood flow

According to Poiseuille's law, volume flow rate through a blood vessel is pro-portional to its radius to the fourth power (V ∝ R4). If an atheroma reduces the radius of an artery from 4 mm to 2 mm, what effect would this have on the blood flow through the artery? A. blood flow would decrease to half (1/2) the value for an artery with radius 4 mm. B. blood flow would decrease to a quarter (1/4) of the value for an artery with radius 4 mm. C. blood flow would decrease to an eighth (1/8) of the value for an artery with radius 4 mm. D. blood flow would decrease to one sixteenth (1/16) of the value for an artery with radius 4 mm

Answer is D: 2 mm is half of 4 mm and according to Poiseuille's law: V∝(‰)^4=1/16

What is a normal pressure in the venous system returning blood to the heart? A. 35 mmHg B. 35 cm water C. 80 mmHg D. 10 cm water

Answer is D: 35 mmHg is BP at arterial end of capillary, so C is also wrong. 17 mmHg is BP at venous end of capillary, 35 cmH2O is ~26 mmHg so choice B is too high 35 cm water = ~26 mmHg 15 cm water = ~ 11 mmHg

Which of the following chemicals would cause blood pressure to decrease when they appear in blood? A. anti-diuretic hormone B. angiotensin II C. aldosterone D. atrial natriuretic peptid

Answer is D: ANP acts to reduce blood volume by: Increasing Na+ excretion at kidneys (blocking release aldosterone); Increasing volume of urine produced; Reducing thirst; Blocking release of ADH. ANP acts to reduce blood pressure by blocking release of the vasoconstrictors adrenaline & noradrenaline and stimulating peripheral vasodilation

Angiotensin II does all of the following except one. Which one? A. stimulates thirst B. causes the release of aldosterone C. causes the release of ADH D. stimulates peripheral vasodilation

Answer is D: Angiotensin II promotes an increase in blood volume and vaso-constriction, but not vasodilation

Which of the following does Angiotensin II cause to happen? A. Atrial natriuretic peptide to be released. B. The collecting ducts in the kidney to become permeable to water. C. The release of antidiuretic hormone to be supressed. D. Aldosterone to be released

Answer is D: Angiotensin II stimulates the adrenal glands to release aldosterone

If an atheroma reduces the diameter of an artery from 2 mm to 1 mm, what effect would this have on the blood flow through the artery? (According to Poiseuille's law, volume flow rate through a blood vessel is proportional to its radius to the fourth power i.e. V ∝ R4). A. blood flow would decrease to half (1/2) the value for an artery with diameter 2 mm. B. blood flow would decrease to a quarter (1/4) of the value for an artery with diameter 2 mm. C. blood flow would decrease to an eighth (1/8) of the value for an artery with diameter 2 mm. D. blood flow would decrease to one sixteenth (1/16) of the value for an artery with diameter 2 mm.

Answer is D: As volume flow rate is proportional to radius to the fourth power, if radius decreases by half, volume flow rate decreases by ½x½x½x½ = 1/16.

Given that a heart pumps out 70 ml of blood with each stroke and beats 70 times per minute, what is the cardiac output? A. 70 ml/min B. 490 ml/min C. 700 ml/min D. 4900 ml/min

Answer is D: Cardiac output, CO=SVxHR= 70ml / beat x 70 beat/min = 4900 mL/min

Hypertension in adults may be defined as: A. Excessive decrease in blood pressure. B. Mean arterial pressure greater than 110 mm Hg. C. Systolic blood pressure less than 100 mm Hg when resting D. Systolic blood pressure persistently greater than 140 mm Hg when resting

Answer is D: Choice B would also be correct if reference was made to "rest-ing". The hypertensive value for children is less

Complete the following sentence correctly for a person at rest. Hypertension A. occurs when blood volume is too low B. refers to the increased blood pressure in the legs while standing C. indicates that resistance to blood flow is low D. is when systolic blood pressure is more than 140 mmHg

Answer is D: Hypertension means a resting BP that is too high. The value beyond which hypertension is identified is 140 mmHg for the systolic reading.

Which of the following will NOT increase cardiac output? A. increasing strength of contraction B. increasing stroke volume C. increasing heart rate D. increasing total peripheral resistance

Answer is D: If peripheral resistance increases, all else being unchanged, CO will fall

Which of the following statements about resting blood pressure is correct? According to the Australian Heart Foundation Classifications: A. High blood pressure is considered greater than 180/110 mmHg B. A systolic reading alone of greater than 140 mmHg is classed as high blood pressure C. If the pulse pressure remains around 1/3 of the systolic reading, then BP is considered normal regardless of the systolic & diastolic readings D. Blood pressure is classed as high if it is greater than 140/90 mmHg

Answer is D: If resting systolic BP is above 140 mmHg and diastolic BP is above 90 mmHg, then a diagnosis of hypertension may be made. Choice A is very high BP

What is the class of anti-hypertensive drug that prevents smooth muscle con-traction, and hence promotes vasodilation called? A. ACE inhibitors. B. beta blockers. C. diuretics D. calcium channel blockers

Answer is D: In order for muscle to contract, calcium is released from the sar-coplasmic reticulum and binds to troponin, which changes its shape and pulls tropomyosin away which exposes actin's binding site. A blocker prevents the release of Ca++ into the muscle cell sarcoplasm

What achieves short term control of blood pressure? A. hormonal mechanisms B. the kidneys C. changes in concentration of chemicals such as O2, CO2, H+, K+. D. neural mechanisms

Answer is D: In the short term, it is the cardio-vascular centre (of the brain). It receives input from higher brain centres (hypothalamus & cerebrum), barore-ceptors & chemoreceptors.

To what does the term ventricular systole refer? A. relaxation of the ventricles. B. relaxation of the atria. C. contraction of the myocardium. D. contraction of the ventricles

Answer is D: ventricular systole is contraction of the ventricles, which does not coincide with relaxation of the atria.

Which of the following would increase arterial blood pressure? A. a decrease in sympathetic impulses along the cardio-accelerator nerves B. an increase in parasympathetic impulses along the vagus nerve C. a decrease in sympathetic impulses along vasomotor nerves D. an increase in sympathetic impulses along vasomotor nerve

Answer is D: Increase the rate of sympathetic impulses along vasomotor nerves would result in vasoconstriction which would increase BP. An increase in para-sympathetic impulses would slow the heart rate, which would decrease BP

What does measuring a patient's blood pressure using the auscultatory method do? A. It offers valuable information related to cardiac preload B. It involves the reporting of audible venous turbulence created by an inflated arm cuff C. It relates to a systolic relaxation of the ventricles D. It reports the Korotkoff sounds heard from a partially compressed artery

Answer is D: Korotkoff sounds are made as blood flows turbulently through a compressed artery. They cease when the artery is completely squashed and no blood flows (this is taken to be the systolic pressure) and also when the artery is not compressed at all. In this case the air pressure in the cuff is equal to or less than the diastolic pressure

Which of the following are two of the factors that influence arterial blood pressure? A. peripheral resistance and gravity. B. cardiac output and the partial pressure of oxygen dissolved in blood. C. blood volume and blood osmotic pressure D. cardiac output and peripheral resistance

Answer is D: Mean arterial blood pressure, MAP = CO x TPR(TPR = total peripheral ressistanc)

Which of the following would cause blood pressure to DECREASE? A. an increase in heart rate B. an increase in total peripheral resistance C. an increase in heart stroke volume D. an increase in parasympathetic impulses along the vagus nerve

Answer is D: Parasympathetic activity decreases heart rate and decreases force of myocardial contraction, hence CO and BP would decrease

Which of the following would produce a DECREASE in heart rate? A. sympathetic impulses along the cardioaccelerator nerves. B. increased sympathetic impulses along the vasomotor nerves C. decreased sympathetic impulses along the vasomotor nerves. D. parasympathetic impulses along the vagus nerve

Answer is D: Parasympathetic stimulation (which almost always utilises the vagus nerve) causes a decrease in heart rate

Colloid osmotic pressure A. is due to all of the dissolved particles in blood B. is the difference in pressure between the arterial end and the venous end of a capillary C. is the difference in pressure between the inside of a capillary and the interstitial fluid D. is due to the plasma proteins in the blood

Answer is D: Plasma proteins (also known as colloids) are responsible for the colloid osmotic pressure of blood

When "colloid osmotic pressure" is used in relation to the blood. What is being referred to? A. the movement of water molecules across the membrane of a red blood cell. B. the filtration pressure in the glomeruli of the kidneys. C. the osmotic pressure forcing water and solute out of capillaries. D. the osmotic pressure due to the plasma proteins

Answer is D: Plasma proteins are known as colloids. They are present in blood but not in the interstitial fluid. That part of the osmotic pressure of blood that they produce is known as colloid osmotic pressure

A plaque in a coronary vessel wall will result in a decrease in the lumen diameter of a coronary artery and in less oxygen being delivered to the heart muscle. Why is this? A. A protruding plaque increases the distance blood needs to travel and this increases resistance to flow. B. A narrow artery restricts blood flow by increasing blood's viscosity. C. The constricted artery causes the pressure gradient to decrease which results in lower blood flow. D. The decrease in artery radius will cause blood volume flow rate to decrease

Answer is D: Poiseuille's law states that volume flow rate is proportional to radius the 4th power so a decrease in radius results in a decrease in flow rate and hence less oxygen being delivered to the myocardium

Which of the following responses best describes term "pulse pressure" A. A mean measurement of the systolic and diastolic readings B. A measurement calculated from 1/3 of the diastolic added to the systolic value C. The lowest audible Korotkoff sound when recording blood pressure D. A measurement of the difference in pressure between systolic and diastolic readings

Answer is D: Pulse pressure is defined as the difference between the maximum and minimum BP values

Which of the following does NOT influence the resistance to blood flow? A. diameter of the arterioles B. temperature of the blood C. haematocrit D. radius of the veins

Answer is D: Resistance to blood flow is of interest on the arterial side of the circulation. Radius of veins is much greater than radius of arteries. Temperature does affect blood flow for example in the situation of extremities with "frostbite"

In which part of the brain is the cardiovascular control centre located? A. the neurohypophysis B. the cerebrum C. the hypothalamus D. the medulla oblongat

Answer is D: The CVC is in the brain stem, specifically in the medulla oblongata.

Which of the following does NOT influence the resistance to blood flow? A. diameter of the arterioles B. temperature of the blood C. haematocrit D. diameter of the veins

Answer is D: The arterial side of the circulation contributes to resistance to blood flow. Hence the veins do not contribute to resistance

If a blood pressure is stated as 16 over 10.6 (in units of kilopascals) this means: A. pulse pressure is 16 kPa. B. diastolic pressure is 10.6 kPa below atmospheric pressure C. systolic pressure is 5.4 kPa above atmospheric pressure D. systolic pressure is 16 kPa above atmospheric pressure

Answer is D: The larger value (16) is the systolic pressure (i.e. maximum blood pressure at end of ventricular contraction) and states by how much the blood pressure is above atmospheric pressure 16 kPa = 120 mmHg

The intravenous cannula that will give the largest flow rate is: A. 0.7 mm diameter 32 mm length B. 0.7 mm diameter 19 mm length C. 1.8 mm diameter 32 mm length D. 1.8 mm diameter 19 mm length

Answer is D: The largest diameter gives the largest flow rate and the shortest length provides the lesser resistance to flow

If the radius of a blood vessel is halved, the blood flow through it drops to one sixteenth its previous value. This statement could be describing which of the following? A. a decrease in pressure gradient B. atherosclerosis C. vasoconstriction D. Poiseuille's law

Answer is D: The statement also describes vasoconstriction, but the reference to a quantity means the Poiseuille's law is the best answer