80 Questions
Which equation represents the relationship between arterial pressure, cardiac output, and total peripheral resistance?
Arterial pressure = cardiac output x total peripheral resistance
During laminar flow, what type of velocity profile is observed?
Parabolic velocity profile
Which factor is used to determine whether flow is likely to be laminar or turbulent?
Reynold's number (Re)
Which of the following is NOT a factor that increases the likelihood of turbulence in blood flow?
Low blood viscosity
What is the equation for Reynold's number (Re)?
Re = (velocity of flow) x (radius of vessel) / viscosity
Which statement is true regarding the effect of flow on viscosity?
Static blood has 100x the viscosity of flowing blood
What is the primary effect of turbulence on blood flow?
Turbulence disrupts flow and increases resistance
According to LaPlace's Law, the tension (T) in a blood vessel wall is proportional to the distending pressure (P) and the radius (R) of the vessel. Which of the following statements is correct?
The tension (T) in a blood vessel wall is directly proportional to the distending pressure (P) and inversely proportional to the radius (R) of the vessel.
Which of the following is NOT a practical consequence of LaPlace's Law?
Regulation of blood flow
Which of the following is responsible for regulating tissue blood flow in arterioles and precapillary sphincters?
Smooth muscle control
What is the purpose of vasomotion in blood vessels?
To regulate blood flow through capillaries
What is the term used to describe the increase in blood flow to highly active tissues?
Active hyperaemia
What is the term used to describe the increase in blood flow that occurs after a temporary blockage of blood supply?
Reactive hyperaemia
Which of the following is responsible for the regulation of arteriolar radius?
Smooth muscle
Which of the following is true about blood flow through capillaries?
It accounts for approximately 5% of total cardiac output at rest.
Which of the following describes the electrical conduction pathways in cardiac muscle?
The electrical activity starts in the sinoatrial node and spreads to the ventricles first.
What is the primary focus of this lecture on cardiac action potentials?
Depolarization events
What does an electrocardiogram (ECG) measure?
The total electrical activity of the heart
What is the term used to describe the coordinated electrical activity in the heart?
Functional syncytium
Which of the following is responsible for modifying the spontaneous electrical activity of the heart?
Sympathetic and parasympathetic nerves
How can the spread of electrical activity throughout the heart be measured non-invasively?
By means of an electrocardiogram (ECG)
What is the relationship between the shape and features of the ECG and the cellular action potentials?
The shape and features of the ECG reflect the cellular action potentials.
Which phase of the cardiac action potential is characterized by rapid depolarization due to an increase in sodium permeability?
Phase 0
During which phase of the cardiac action potential do calcium ions enter the cell through L-type channels?
Phase 2
What is the effect of elevated internal calcium levels during the cardiac action potential?
Stimulates opening of potassium channels
What is the primary effect of sympathetic stimulation on pacemaker activity?
Increased cAMP production
How does parasympathetic stimulation affect the membrane potential of pacemaker cells?
Hyperpolarizes the membrane potential
What is the intrinsic pacemaker of the heart?
Sinoatrial node (SAN)
What is the conduction velocity in atrial and ventricular fibers?
0.3-0.5 m/s
What does the Q-T interval on an electrocardiogram (ECG) represent?
Ventricular repolarization
Which of the following is a possible mechanism of primary hypertension?
Increased sympathetic system activity
What are the possible mechanisms of secondary hypertension?
Renin-angiotensin-aldosterone system dysfunction
What are the consequences of hypertension?
All of the above
How is hypertension treated?
All of the above
What type of hypertension affects the pulmonary system?
Pulmonary hypertension
Which of the following is NOT a possible contributor to systemic hypertension?
Genetics
Which of the following is the most potent endogenous vasoconstrictor?
Endothelin-1 (ET-1)
Which of the following is responsible for promoting sodium and water excretion in the kidneys?
Nitric oxide (NO)
Which of the following is NOT a potential cause of secondary hypertension?
Primary hypertension
Which of the following is NOT a consequence of systemic hypertension?
Increased nitric oxide production
Which of the following is a major risk factor for cardiovascular disease?
Increased blood pressure in the arteries of the lungs
What is the definition of systemic arterial hypertension?
Systolic blood pressure > 140 mmHg and/or Diastolic blood pressure > 90mmHg
Which of the following is NOT a possible contributor to systemic hypertension?
Increased blood pressure in the arteries of the lungs
Which of the following is responsible for the secretion of aldosterone from the adrenal glands?
Angiotensin II
Which of the following is the primary cation in the extracellular fluid (ECF)?
Sodium (Na+)
Which of the following is NOT a risk factor for hypertension?
Age
What is the primary cation in the extracellular fluid (ECF)?
Sodium
Which of the following is responsible for the conversion of angiotensin I to angiotensin II?
Angiotensin converting enzyme (ACE)
Which of the following is true about blood flow through capillaries?
Blood flow is slowest in capillaries compared to other blood vessels.
What is the primary effect of turbulence on blood flow?
Increased resistance
Which of the following is a possible mechanism of primary hypertension?
Increased sympathetic system activity
What is the primary effect of turbulence on blood flow?
Increased resistance
What is the equation for Reynold's number (Re)?
Re = (velocity) x (density) x (length) / (viscosity)
Which of the following is NOT a possible contributor to systemic hypertension?
Decreased circulating factors
Which of the following is responsible for promoting sodium and water excretion in the kidneys?
Renin-angiotensin-aldosterone system (RAAS)
Which of the following is NOT a risk factor for hypertension?
Increased sympathetic activity
Which of the following is the correct order of the cleavage steps in the renin-angiotensin-aldosterone system (RAAS)?
Angiotensinogen -> Renin -> Angiotensin I -> ACE -> Angiotensin II
Which of the following is NOT a consequence of hypertension?
Increased nitric oxide production
Which of the following is the most potent endogenous vasoconstrictor?
Endothelin-1 (ET-1)
Which of the following is NOT a possible mechanism of secondary hypertension?
Increased sympathetic activity
Which of the following is NOT a broad category of events that can lead to dysrhythmias?
Circus re-entry
Which type of dysrhythmia is considered to be more serious?
Ventricular tachycardia
Which part of the heart has the fastest inherent rate and acts as the pacemaker?
SAN
Which of the following is true about First Degree Heart Block?
AVN is only slightly affected and conduction is slowed
What is the most likely consequence of Third Degree Heart Block?
The ventricles depolarise at their inherent rate
What can cause the development of ectopic pacemakers in the heart?
Abnormalities in the conducting system
Which of the following is NOT a category in the Vaughn-Williams Classification system for anti-dysrhythmic drugs?
Class IV
What is the primary effect of the accessory electrical connection between the atria and ventricles in Wolf-Parkinson-White Syndrome?
Shortening the PR interval
What is the main characteristic of circuits involved in circus re-entry movements?
Short length and high impulse frequency
What is the primary cause of the grey area in the cardiac conduction system?
Insufficient current generation
Which of the following is responsible for the conduction of electrical impulses between the atria and ventricles in the heart?
Bundle of His
What is the term used to describe a condition where the AV node is only slightly affected and conduction is slowed, resulting in an abnormally long P-R interval?
First Degree Heart Block
Which of the following describes a type of second degree heart block where most beats are conducted with a constant P-R interval, but occasionally there is an atrial depolarisation without a ventricular depolarisation?
Mobitz (type 2)
Which of the following is NOT a broad category of event that can give rise to dysrhythmias?
Circus re-entry
Which of the following is NOT a common type of tachyarrhythmia?
Ventricular ectopic
Which part of the heart has the fastest inherent rate and acts as the pacemaker?
SAN
Which part of the heart is responsible for generating the impulse that initiates the cardiac action potential?
AV node
What is the main characteristic of Wolf-Parkinson-White Syndrome?
Short PR interval and early upstroke of QRS complex
What is the primary effect of Class III anti-dysrhythmic drugs?
Prolong the duration of action potential repolarisation
What is the effect of unidirectional block in the orthodromic direction?
Increased frequency of impulses generated
Test your knowledge on arterial blood flow and peripheral resistance in the vasculature with this quiz. Learn about factors affecting resistance to blood flow, regulation of tissue blood flow, and the role of capillaries. Challenge yourself with questions on fluid flow and the parabolic velocity profile during laminar flow.
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