B5 Lt MCQ

What vessels of the vasculature are best suited to regulate blood flow in the systemic circulation? Arteries Arterioles Capillaries Veins

Arterioles Indeholder lag med glat muskulatur som gør at de kan ændre radius og dermed modstand

How does the velocity of blood flow relate to the total cross-sectional area of a group of blood vessels? As total cross-sectional area decreases, velocity decreases. As total cross-sectional area decreases, velocity stays the same. As total cross-sectional area increases, velocity decreases. As total cross-sectional area increases, velocity stays the same.

As total cross-sectional area increases, velocity decreases.

When two vectors are the same size (have the same magnitude) and are moving in opposite directions along the lead axis (in line with the positive electrode of the lead) as in the picture, what will appear on the ECG recording? A negative deflection A positive deflection An isoelectric (flat) line

An isoelectric (flat) line

At what angle does lead III view the heart from? That is, at what angle on the hexaxial system of limb lead axes is the positive electrode of lead III located? +60° +120° 180° -90°

+120°

Lead I is at ____, Lead II is at ____, and Lead III is at ____. 0°; +60°; +120° 0°; +90°; +180° +30°; +90°; +150°

0°; +60°; +120°

For an individual with a heart rate of 70 BPM and a stroke volume of 70 mL, what is their CO? 1 L/min 5 L/min 1 mL/min 5 mL/min

5 L/min 70 BPM x 70 mL = 4900 mL/min = 5 L/min

What is the normal range for MABP? 60-90 mmHg 70-105 mmHg 100-140 mmHg 110-150 mmHg

70-105 mmHg

What does a depolarizing wave that travels away from a positive electrode cause in the ECG recording? A negative deflection A positive deflection An isoelectric (flat) line

A negative deflection

Which part of the vasculature would have the slowest localized flow rate through each vessel? Aorta Arteries Capillaries Veins

Capillaries

Arterial blood pressure can be calculated from which equation? CO × PP DP + 1/3 PP SP × 1/3 TPR TPR × SV

DP + 1/3 PP

The ECGs of which two leads are sufficient for basic calculation of the cardiac axis? I and II I and aVF I and aVL II and aVF

I and aVF

Which lead is most likely to show an increased positive R amplitude in left ventricular hypertrophy? Lead II Lead III Lead aVF Lead aVR

Lead II

Which limb lead's axis is the closest to a normal cardiac axis vector? Lead I Lead II Lead III Lead aVF Lead aVL Lead aVR

Lead II

Blood flow equals the pressure difference (ΔP) between two points divided by which of the following? Arterial diameter Blood volume Osmotic pressure Resistance

Resistance

What properties of a vessel make it easy to stretch? Large elastance and large compliance Large elastance and small compliance Small elastance and large compliance Small elastance and small compliance

Small elastance and large compliance

What is the most important force in venous flow? Gravity The pressure gradient generated by the heart The skeletal muscle pump The thoracic (respiratory) pump

The pressure gradient generated by the heart

A vessel with a low compliance requires a greater pressure to accommodate a given volume. True False

True

What is the basis for the sounds referred to as Korotkoff sounds? Laminar blood flow Maximal blood flow Turbulent blood flow

Turbulent blood flow

How can the same volume of blood return to the heart each minute as is ejected from the heart, when the velocity of blood flow in the veins is significantly less than the velocity of the blood flow in the arteries? Veins have a higher blood volume than arteries. The pressure in the veins compensates for the lower blood velocity.

Veins have a higher blood volume than arteries.

What is the most important determinant of the volume of blood flowing through a vessel at a constant pressure? Blood viscosity Blood cell count Vessel length Vessel radius

Vessel radius

The isovolumetric contraction phase only lasts about 30 ms, but it is an incredibly important part of the cardiac cycle. What happens during the isovolumetric contraction phase that is so important? a) A high pressure is generated which is needed to overcome the aortic pressure. b) The high pressure generated in the ventricle helps to sufficiently close the stiff mitral valve. c) The pressure generated rapidly increases blood flow through the aortic valve.

a) A high pressure is generated which is needed to overcome the aortic pressure.

Which molecule do parasympathetic postganglionic neurons release? a) Acetylcholine b) Epinephrine c) Norepinephrine

a) Acetylcholine

Which of these neurotransmitters is always released at the postganglionic synapses in the parasympathetic nervous system? a) Acetylcholine b) Epinephrine c) Norepinephrine

a) Acetylcholine

Which of these neurotransmitters is released at the preganglionic-postganglionic synapses in the sympathetic nervous system? a) Acetylcholine b) Epinephrine c) Norepinephrine

a) Acetylcholine

Which receptor does norepinephrine bind to on effector cells? a) Adrenoceptors b) Muscarinic receptors c) Nicotonic receptors

a) Adrenoceptors

Which statement regarding bulk flow and diffusion is false? a) Air moves by diffusion from the bronchi downwards. b) Bulk movement of air ceases at the alveolar ducts. c) Movement of gas between the alveolar ducts and alveoli occurs by diffusion, not bulk flow. d) There is no longer any bulk flow of air in the alveolar ducts.

a) Air moves by diffusion from the bronchi downwards.

Which statement regarding flow and resistance in the airways is false? a) Airflow is more laminar in the nasal cavity than it is in the bronchioles. b) Turbulent flow allows more efficient removal of dust and microorganisms from inspired air. c) Turbulent flow helps bring inspired air into contact with the respiratory epithelium.

a) Airflow is more laminar in the nasal cavity than it is in the bronchioles.

Which law states that pressure exerted by a gas is directly proportional to temperature, if the volume of the gas is held constant? a) Amontons' law b) Boyle's law c) Charles' law d) The law of gravity

a) Amontons' law

Which baroreceptors monitor the pressure of blood going to the systemic circulation? a) Baroreceptors in the aortic arch b) Baroreceptors in the carotid sinus

a) Baroreceptors in the aortic arch

Which statement is true regarding heart valves during isovolumetric contraction? a) Both the mitral and aortic valves are closed. b) The mitral valve is closed while the aortic valve is open. c) The mitral valve is open while the aortic valve is closed

a) Both the mitral and aortic valves are closed.

In response to an increase in MABP, how is cardiac output (CO) affected by the baroreflex? a) CO decreases b) CO increases c) CO remains unchanged

a) CO decreases Både HR og SV reduceres CO = HR x SV

Which of the following is responsible for generating the first heart sound, and the second heart sound? a) Closure of the AV valves, then closure of the semilunar valves. b) Closure of the semilunar valves, then closure of the AV valves.

a) Closure of the AV valves, then closure of the semilunar valves

Which statement regarding the diaphragm is true? a) Contraction of the diaphragm causes the muscle to flatten. b) The diaphragm is innervated by intercostal nerves. c) The diaphragm is important for quiet breathing but not forced breathing. d) Relaxation of the diaphragm increases the volume of the thoracic cavity.

a) Contraction of the diaphragm causes the muscle to flatten.

Which statement regarding the internal and external intercostal muscles is true? a) Contraction of the internal intercostals pulls the ribs downward and inward. b) The external intercostals are important for decreasing the volume of the thoracic cavity. c) The internal intercostals are involved in quiet and forced inspiration. d) The intercostal muscles are innervated by branches of the phrenic nerve. e) The intercostal muscles assist the diaphragm by pushing it upwards.

a) Contraction of the internal intercostals pulls the ribs downward and inward.

Which statement regarding coronary blood flow is true? a) Coronary blood flow falls abruptly as the ventricular muscle contracts. b) Coronary blood flow increases in systole. c) Coronary blood flow is lower during diastole.

a) Coronary blood flow falls abruptly as the ventricular muscle contracts.

Which of these would be seen if the effects of angiotensin II were inhibited? a) Decreased ADH release from posterior pituitary b) Decreased salt and water excretion by the kidney c) Peripheral vasoconstriction

a) Decreased ADH release from posterior pituitary

What effect does breathing through the mouth have on resistance to flow? a) Decreases resistance b) Increases resistance c) No change in resistance

a) Decreases resistance

Which period of the cardiac cycle shortens most with exercise? a) Diastole b) Systole

a) Diastole

What drives the flow of blood through the vascular system during diastole? a) Elastic recoil of the large arteries. b) Momentum of the blood that results from ventricular contraction. c) Vasodilation of the small arteries, to decrease the resistance to flow.

a) Elastic recoil of the large arteries.

If the overall electrical activity vector of the heart points superiorly (upward, toward the head) for a short time, how will this look on an ECG recording? a) It depends on which "lead" records the electrical activity. b) The "upward" vector means the ECG recording will have a downward deflection. c) The "upward" vector means the ECG recording will have an upward deflection.

a) It depends on which "lead" records the electrical activity.

When a wave of repolarization travels toward a lead, how is this represented on an ECG tracing? a) Negative (downward) b) No change (horizontal) c) Positive (upward)

a) Negative (downward)

Would turbulent flow require the same pressure as laminar flow to achieve the same flow rate? a) No b) Yes

a) No

A simple lead II recording is performed on Olivia during a period when she is experiencing atrial flutter. Which component of the ECG trace would you expect to look abnormal? a) P wave b) QRS complex c) T wave

a) P wave (atriel depolarisering)

The coordinated action of chordae tendineae, papillary muscles, and ventricular walls prevent the cusps of the mitral valve from inverting into the atria. How is this achieved? a) Papillary muscles anchor the chordae tendineae to the ventricular wall to create tension and prevent the cusps inverting into the atria. b) Papillary muscles contract and pull the cusps closer to the ventricular wall to prevent cusps inverting into the atria

a) Papillary muscles anchor the chordae tendineae to the ventricular wall to create tension and prevent the cusps inverting into the atria.

What is the effect of acetylcholine binding to nicotinic receptors? a) Synaptic transmission in both sympathetic and parasympathetic pathways. b) Synaptic transmission in the parasympathetic pathway. c) Synaptic transmission in the sympathetic pathway.

a) Synaptic transmission in both sympathetic and parasympathetic pathways.

Which statement is true for the ANS? a) The ANS has both afferent and efferent components. b) The ANS is only an efferent system. c) The ANS is only an afferent system.

a) The ANS has both afferent and efferent components.

What determines blood volume? a) The amount of sodium chloride (NaCl) in the extracellular fluid. b) The concentration of sodium chloride (NaCl) in the extracellular fluid.

a) The amount of sodium chloride (NaCl) in the extracellular fluid.

Ventricular filling slows in the second half of this period, as indicated by a plateau in the ventricular volume trace. Why do you think that passive filling of the ventricles slows? a) The pressure gradient for blood to flow from the atria into the ventricles becomes less. b) The ventricles have reached maximum blood capacity, and cannot hold any more blood. c) Ventricular pressure is now greater than atrial pressure, so there is a tendency for blood to flow back into the atria.

a) The pressure gradient for blood to flow from the atria into the ventricles becomes less.

How does venoconstriction affect cardiac output? a) Venoconstriction helps to push blood back to the heart to increase venous return, stroke volume, and cardiac output. b) Venoconstriction increases the resistance to blood flow in the veins. This will reduce venous return, stroke volume, and cardiac output.

a) Venoconstriction helps to push blood back to the heart to increase venous return, stroke volume, and cardiac output.

The limb leads view the heart in the ______ plane, while the chest leads view the heart in the ______ plane. a) coronal; transverse b) transverse; coronal

a) coronal; transverse

At rest, systole lasts approximately 0.27 s. What then, is the duration of a cardiac cycle? a) 0.5 s b) 0.8 s c) 1.1 s

b) 0.8 s 0,27 x 3

Short-term regulation of blood pressure does not involve changes in which of the following? a) Blood vessel diameter b) Blood volume c) Heart rate

b) Blood volume

To increase oxygen delivery to working muscles during exercise, heart rate increases. Barry's heart rate has increased from 60 beats per minute (bpm) at rest, to 120 bpm during a run. What happens to the time taken for each cardiac cycle? a) Increases b) Decreases c) Stays the same

b) Decreases Fra 1 sek (60 bpm) til 0,5 sek (120 bpm)

Which event of the cardiac cycle occurs while the aortic valve is open? a) Atrial contraction b) Ejection c) Isovolumetric contraction d) Isovolumetric relaxation e) Rapid filling

b) Ejection

At the end of the ejection phase there is no blood remaining in the ventricles. a) True b) False

b) False 50-70 mL tilbage

At rest, the ventricles are filled mostly during atrial contraction. a) True b) False

b) False Kun 10% af ventrikulær fyldning --> 30% ved fysisk aktivitet

Some people find it more difficult to breathe in a humid environment. Which of these statements might explain this? a) High water vapor decreases the radius of the airway. b) High water vapor increases the density of the air. c) High water vapor increases the environmental temperature.

b) High water vapor increases the density of the air.

An increase in MABP will result in which of the following? a) Decreased baroreceptor activity b) Increased arteriolar diameter c) Increased sympathetic activity d) Increased TPR

b) Increased arteriolar diameter

Inspired air first makes contact with the curved shelves of bone in the nasal cavity, the conchae. The shape of these conchae create considerable turbulent airflow. What effect does this have on resistance to flow? a) Decreases resistance b) Increases resistance c) No change in resistance

b) Increases resistance

Which event of the cardiac cycle occurs immediately after the mitral valve closes? a) Ejection b) Isovolumetric contraction phase c) Isovolumetric relaxation phase d) Rapid filling

b) Isovolumetric contraction phase

Which statement regarding flow-volume loops is true? a) Expiratory flow is shown as negative flow. b) It is the expiratory information that is diagnostically significant. c) It requires forced breathing. d) Time is plotted on the x-axis.

b) It is the expiratory information that is diagnostically significant.

Which lead is most closely aligned with the direction of ventricular depolarization? a) Lead I b) Lead II c) Lead III

b) Lead II Har dermed størst R-bølge, og viser P- og T-bølgen som positiv.

When Mei quickly stood after lying down on this hot, humid day, she felt lightheaded and fainted. Why was this? a) When she stood up, blood had to now return from her legs to her heart against gravity. b) Mei's veins are not rigid, but distensible. c) Because it was hot and humid, the blood vessels in Mei's skin were dilated and there was not enough blood available to her brain when she stood up.

b) Mei's veins are not rigid, but distensible.

How would urine production be affected by decreased ADH release? a) Less urine production b) More urine production c) No change in urine production

b) More urine production Mindre ADH --> mindre vand reabsorberes af nyrerne ind i blodstrømmen.

Which of the following statements about the residual volume (RV) is true? a) RV is about 12% of the total volume of air that the lungs contain. b) RV is approximately 1.2 L in a healthy young adult. c) RV is the volume of air that can be expired at the end of a maximal expiration.

b) RV is approximately 1.2 L in a healthy young adult.

Which statement regarding the diaphragm is false? a) Contraction of the diaphragm increases the volume of the thoracic cavity. b) Relaxation of the diaphragm causes the muscle to flatten. c) The diaphragm is the primary muscle used in breathing. d) The esophagus, blood vessels, and nerves all pass through a series of openings in the diaphragm.

b) Relaxation of the diaphragm causes the muscle to flatten.

What does isovolumetric relaxation refer to? a) Contraction of the ventricles when both the mitral and aortic valves are closed. b) Relaxation of the ventricles when both the mitral and aortic valves are closed. c) Relaxation of the ventricles when both the mitral and aortic valves are open.

b) Relaxation of the ventricles when both the mitral and aortic valves are closed.

What is the result of epinephrine binding to an α1 adrenoceptor? Note: this receptor uses the αq subunit. a) No effect. b) Smooth muscle contraction c) Smooth muscle relaxation

b) Smooth muscle contraction

Consider the relationship between electrical activity in the heart, and cardiac muscle contraction. What relationship would you expect between the QRS complex of an ECG, and the start of left ventricular contraction (ventricular systole)? a) The QRS complex and left ventricular contraction occur at the same time. b) The QRS complex would precede the start of left ventricular contraction. c) The QRS complex would occur after the start of left ventricular contraction.

b) The QRS complex would precede the start of left ventricular contraction.

Why does the pressure generated in the left ventricle have to be greater than that generated by the right ventricle? a) The aortic valve is stiffer than the pulmonary valve, therefore a greater pressure is required to open it. b) The left ventricle needs to generate more pressure to overcome the greater vascular resistance of the systemic circulation. c) The left ventricle pumps a larger volume of blood than the right ventricle.

b) The left ventricle needs to generate more pressure to overcome the greater vascular resistance of the systemic circulation.

When you palpate (feel) an arterial pulse, what are you feeling? a) The movement of blood through the artery. b) The propagating pressure wave through the artery. c) Vibrations caused by closure of the semilunar valve.

b) The propagating pressure wave through the artery.

Is resistance higher when flow is laminar or turbulent? a) Laminar b) Turbulent

b) Turbulent

During inspiration, the diaphragm and external intercostal muscles ________, causing the thoracic cavity ________. a) contract; to compress b) contract; to expand c) contract; to relax d) relax; to contract e) relax; to expand

b) contract; to expand

ECG leads detect the electrical activity in the heart. By convention, depolarizing waves that travel toward the positive electrode cause a ______ deflection, while waves that travel away cause a ______ deflection. a) negative; positive b) positive; negative

b) positive; negative

On average, how many postganglionic neurons does a single preganglionic neuron synapse with? a) 1 b) 2-3 c) 8-9 d) 32+

c) 8-9

What does ECG measure? a) Contraction and relaxation of cardiac muscle. b) Contraction and relaxation of the ventricles. c) Electrical activity of cardiac muscle.

c) Electrical activity of cardiac muscle.

Which statement regarding expiratory reserve volume (ERV) is false? a) ERV is approximately 1.5 L in a healthy young adult. b) ERV is the volume of air that can be expired from the end of a normal inspiration. c) Not all of the ERV can be expired.

c) Not all of the ERV can be expired.

When a wave of depolarization travels toward a lead, how is this represented on an ECG tracing? a) Negative deflection (downward) b) No change (horizontal) c) Positive deflection (upward)

c) Positive deflection (upward)

What could a low FEV1/FVC ratio indicate? a) That an individual is exercising. b) That an individual is forcefully exhaling. c) That an individual may have obstructive lung disease. d) That an individual may have restrictive lung disease.

c) That an individual may have obstructive lung disease.

According to Starling's law, the strength of ventricular contraction will adjust to match venous return. This is determined by which of the following? a) Heart rate b) Peripheral resistance c) The amount of blood returning to the right atrium d) The size of the left ventricle

c) The amount of blood returning to the right atrium

What does an ECG measure? a) An individual cardiac action potential. b) Mechanical events in the heart. c) The collective electrical activity of the heart. d) The movement of the cardiac muscles.

c) The collective electrical activity of the heart.

What is the function of the mucus in the trachea? a) The mucus assists with swallowing food. b) The mucus helps stimulate blood flow to the area. c) The mucus helps trap foreign particles before they can enter the lungs.

c) The mucus helps trap foreign particles before they can enter the lungs.

With all other factors constant, which statement is true regarding the relationships between pressure, volume, and temperature? a) Pressure of a gas is inversely proportional to temperature. b) The hotter the water vapor, the lesser its contribution to atmospheric pressure. c) Volume of a gas is directly proportional to temperature

c) Volume of a gas is directly proportional to temperature

Which component of the electrical conduction system is the "pacemaker"? a) AV node b) Bundle of His c) Purkinje fibers d) SA node

d) SA node

The dominant electrical activity moves away from lead aVR. What does this mean for the QRS complex, the P wave, and the T wave in a lead aVR ECG tracing? a) The QRS complex and the P wave are negative, but the T wave is positive. b) The QRS complex and the T wave are negative, but the P wave is positive. c) The QRS complex is negative, but the P and T waves are positive. d) The QRS complex, P wave, and T wave are all negative.

d) The QRS complex, P wave, and T wave are all negative.

The surface of the conchae are lined with ciliated respiratory epithelium, which secretes mucus and fluid. Which of the following is not a function of the conchae or respiratory epithelium? a) Fine hairs and mucus trap dust particles or potentially harmful microorganisms that may be present. b) They increase the turbulence of inspired air to ensure greater air contact with the respiratory epithelium. c) They have a large surface area to help warm, filter, and humidify inspired air. d) The curved bone shape ensures airflow is smooth (or laminar) through the respiratory system.

d) The curved bone shape ensures airflow is smooth (or laminar) through the respiratory system.

The mitral valve snaps shut when _______ pressure becomes greater than _______ pressure. a) atrial; venous b) atrial; ventricular c) ventricular; aortic d) ventricular; atrial

d) ventricular; atrial

Relaxation of smooth muscle in the arteriolar wall ________ the radius, which ________ the resistance and thus ________ the flow. decreases; decreases; increases increases; decreases; increases increases; increases; decreases

increases; decreases; increases