Pathophysiology Exam 4
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Questions and Answers

What effect does sympathetic stimulation have on the action potential of the SA node?

  • It decreases the depolarization rate.
  • It accelerates the action potential firing rate. (correct)
  • It increases the threshold potential.
  • It causes a negative chronotropic effect.

Which condition leads to an increased resting membrane potential (RMP)?

  • Acidosis
  • Hypokalemia (correct)
  • Dehydration
  • Hyperkalemia

What is the conduction rate of the AV node in m/s?

  • 2
  • 1
  • 0.5
  • 0.05 (correct)

What is the role of epinephrine in relation to the SA node?

<p>It enhances the pace of the SA node by acting like norepinephrine. (A)</p> Signup and view all the answers

Which of the following can cause negative chronotropic effects?

<p>Beta-adrenergic receptor antagonists (A), Parasympathetic stimulation (B)</p> Signup and view all the answers

What effect does depolarization have on the membrane potential of cardiomyocytes?

<p>It flips the membrane to a positive potential. (B)</p> Signup and view all the answers

Which part of the heart initiates the depolarization wave?

<p>SA node (B)</p> Signup and view all the answers

What is a consequence of the AV node being slow conducting tissue?

<p>It causes a flatline in the ECG baseline during contraction. (C)</p> Signup and view all the answers

What causes the peak of the ventricular septal depolarization to show a negative deflection?

<p>The depolarization moving from left to right. (D)</p> Signup and view all the answers

Why is atrial repolarization not visually represented in the ECG?

<p>It coincides with ventricular depolarization. (B)</p> Signup and view all the answers

What is the primary function of the specialized anatomy described?

<p>To pump blood throughout the body (D)</p> Signup and view all the answers

What role do intercalated disks play in the heart's function?

<p>They connect myocytes together (B)</p> Signup and view all the answers

Which component strengthens the connections between heart muscle cells?

<p>Desmosomes (A)</p> Signup and view all the answers

What type of junctions are responsible for electrical connections in cardiac tissue?

<p>Gap junctions (C)</p> Signup and view all the answers

Why is it important for cardiac muscle cells to depolarize in a specific order?

<p>To ensure coordinated contractions (B)</p> Signup and view all the answers

What is the purpose of the smooth, slippery structure surrounding the heart?

<p>To prevent the heart from getting stuck (A)</p> Signup and view all the answers

Which type of blood do veins primarily return to the heart?

<p>Deoxygenated blood (D)</p> Signup and view all the answers

What role does the conduction system of the heart play?

<p>Coordinates electrical impulses for contraction (A)</p> Signup and view all the answers

What does the presence of cardiac troponin (cTn) in the serum indicate?

<p>Cellular damage and severe pathology (D)</p> Signup and view all the answers

What is primarily responsible for causing Acute Coronary Syndromes (ACS)?

<p>Coronary thrombus (D)</p> Signup and view all the answers

Which type of myocardial infarction is associated with the most severe ischemic damage?

<p>Transmural infarction (A)</p> Signup and view all the answers

Which factors are significant in determining the severity of EKG changes in ACS?

<p>Size of the thrombus (D)</p> Signup and view all the answers

Why is the endocardium more vulnerable to ischemia compared to the epicardium?

<p>It is less well perfused (C)</p> Signup and view all the answers

What physiological change occurs due to vessel occlusion in ACS?

<p>Decreased oxygen delivery to cardiac tissues (C)</p> Signup and view all the answers

What is the anatomical direction of blood perfusion in coronary arteries?

<p>From epicardium to endocardium (A)</p> Signup and view all the answers

Which of the following is NOT a sign or symptom of ACS?

<p>Improved exercise tolerance (A)</p> Signup and view all the answers

What does ST elevation in an EKG indicate?

<p>A transmural infarct (STEMI) (C)</p> Signup and view all the answers

Which EKG change is associated with a non-STEMI?

<p>ST depression (C), T wave inversion (D)</p> Signup and view all the answers

Why does the EKG trace begin with a positive deflection during subendocardial infarcts?

<p>Positive charge is moving toward the electrode (B)</p> Signup and view all the answers

What does a 'true baseline' EKG represent?

<p>Complete depolarization of the ventricles (B)</p> Signup and view all the answers

What symptom led the EMT to suspect a heart attack in Art?

<p>Crushing substernal pain (B)</p> Signup and view all the answers

Why was Art given oxygen during his emergency treatment?

<p>To increase blood flow to the heart (C)</p> Signup and view all the answers

What is the significance of Art being pale and sweaty?

<p>Helps confirm a heart attack suspicion (D)</p> Signup and view all the answers

What is the purpose of starting an IV for Art?

<p>To administer fluids and medications (D)</p> Signup and view all the answers

What is a characteristic EKG alteration in atrial flutter?

<p>Saw tooth P waves (B)</p> Signup and view all the answers

In the case of re-entry in the ventricles, which tissue is considered susceptible?

<p>Ventricular myocytes (B)</p> Signup and view all the answers

What primary method is suggested to treat paroxysmal supraventricular tachycardia (PSVT)?

<p>Changing the automaticity of the heart (D)</p> Signup and view all the answers

What happens to conduction and re-entry during ischemia?

<p>Conduction slows down, creating reentrant loops (B)</p> Signup and view all the answers

In sustained tachycardia, what effect does uncoordinated stimulation have on the ventricular QRS?

<p>Wide QRS complexes (D)</p> Signup and view all the answers

What is the atrial rate typically seen in atrial flutter?

<p>300 bpm (A)</p> Signup and view all the answers

What condition is indicated by damaged tissue conducting signals retrograde?

<p>STEMI (D)</p> Signup and view all the answers

Which medication is mentioned as a beta-blocker for treating supraventricular tachycardia?

<p>Propranolol (B)</p> Signup and view all the answers

Flashcards

Intercalated Disks

Structures that connect cardiac muscle cells, maintaining the heart's shape and function.

Desmosomes

Structures providing strength to myocardial connections, preventing tearing.

Gap Junctions

structures allowing electrical signals to transmit between cardiac muscle cells efficiently

Myocardium

The muscular wall of the heart, responsible for pumping blood.

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Cardiomyocytes

Individual heart muscle cells.

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Specialized Anatomy in Heart

Structural adaptations in the heart enables specialized function(pumping blood throughout the body).

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Conduction System

Specialized cells that initiate and transmit electrical impulses to coordinate heart muscle contractions.

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Depolarization (heart)

Electrical stimulation triggering heart muscle contraction by changing the cell's electrical charge.

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Heart's Conduction Process

The order in which the heart cells contract, crucial for effective pumping.

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Heart's Contraction (Conduction Pathway)

Contraction of the heart chambers is dependent on correct transmission of electrical impulses.

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SA Node Action Potential

The electrical signal that originates in the sinoatrial (SA) node, the heart's pacemaker, responsible for initiating the heartbeat.

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Positive Chronotropy

Factors that increase the heart rate.

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Negative Chronotropy

Factors that decrease the heart rate.

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Sympathetic Stimulation

Activation of the sympathetic nervous system, increasing heart rate.

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Parasympathetic Stimulation

Activation of the parasympathetic nervous system, decreasing heart rate.

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Threshold Potential (TP)

The minimum level of membrane potential required to initiate an action potential.

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Resting Membrane Potential (RMP)

The electrical potential difference across the cell membrane when the cell is at rest.

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Conduction Rate

The speed at which an electrical signal travels through different parts of the heart.

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Tissue Conduction Rates

Different parts of the heart have different speeds of electrical signal transmission.

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Acidosis

A condition of abnormally low blood pH.

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Hypokalemia

A condition of low potassium levels in the blood.

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Hyperkalemia

A condition of high potassium levels in the blood.

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Depolarization

The process of a cardiomyocyte's membrane flipping from a negative to a positive potential.

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SA Node

The source of the depolarization wave in the heart, initiating the heart's electrical activity.

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AV Node

A region of slow-conducting tissue in the heart, delaying the depolarization wave.

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QRS complex (ECG)

The portion of an electrocardiogram representing ventricular depolarization.

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Ventricular Septum

The wall separating the left and right ventricles of the heart, which depolarizes.

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PR interval

The time delay in the ECG between atrial and ventricular depolarization.

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ECG Baseline

The flat line on an ECG during heart rest between heartbeats (no electrical activity).

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Atrial repolarization

The return of atrial cells to their resting potential after contracting.

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Acute Coronary Syndromes (ACS)

A group of conditions where blood flow to the heart is suddenly reduced, potentially causing heart damage.

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Cardiac Troponin (cTn)

A protein released into the blood when heart muscle cells are damaged.

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Creatinine Kinase (CK)

Another biomarker released into the blood when cells in the body are damaged, including heart muscle cells.

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Coronary Thrombus

A blood clot inside a coronary artery, blocking blood flow.

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Vessel Occlusion

Blockage of a blood vessel.

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STEMI

A severe type of heart attack where the plaque cuts off blood flow completely.

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NSTEMI

A less severe type of heart attack where the plaque cuts off some but not all blood flow.

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Subendocardial Infarction

A heart attack that affects the inner part of the heart wall, less severe.

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Transmural Infarction

A heart attack affecting the whole thickness of the heart wall, more severe.

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EKG Changes in Infarction

EKG changes differ depending on the extent of heart damage. Transmural infarcts show ST elevation, while subendocardial infarcts show ST depression.

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ST Elevation

A positive deflection on the EKG tracing, indicating a complete blockage of blood flow to the heart tissue. Often shows complete blockages.

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ST Depression

Indicates partial blockage or damage to the heart tissue and is often seen in subendocardial infarcts. A negative deflection on the EKG tracing.

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Chest Pain Cause

Chest pain in Art is likely due to a heart attack.

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Pale and Sweaty in Heart Attack

Pale and sweaty skin are symptoms associated with reduced blood flow to the body, a sign of a potential heart attack.

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Oxygen in Heart Attack

Oxygen is given to increase oxygen supply to the body, which helps compensate for reduced blood flow.

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IV in Heart Attack

IV fluids like fluids can be given to ensure the body has enough fluids and electrolytes, crucial during emergencies.

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Supraventricular Tachycardia (SVT)

Rapid heart rhythm originating above the ventricles.

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Atrial Flutter

A type of SVT with a rapid, regular atrial rhythm (often 300 bpm).

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Re-entry

A heart rhythm problem where electrical signals circulate in a loop, causing rapid beating.

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Paroxysmal SVT (PSVT)

SVT that comes and goes (attacks).

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Saw-toothed P waves

Characteristic EKG pattern seen in atrial flutter.

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AV conduction

Transmission of electrical signals from the atria to the ventricles.

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Ventricular rate

The rate at which the ventricles contract (beat per minute).

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Re-entrant Loop

Circuitous path of electrical signals within the heart.

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EKG alterations in re-entry ventricles

Changes in the EKG pattern related to the abnormal ventricular electrical pathways in re-entry arrhythmias.

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Ventricular Re-entry

Rapid heart rhythm originating within the ventricles due to a re-entrant circuit.

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Damaged tissue conduction

Slowed conduction in a part of the heart as due to damaged tissues.

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Retrograde

Movement of electrical signal in the opposite direction.

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