Anatomy & Physiology of the Heart

<p>It increases heart rate and contractility. (D)</p> Signup and view all the answers

<p>Cardiac muscle uses both extracellular and SR Ca²⁺. (A)</p> Signup and view all the answers

<p>Electrical activity from multiple angles. (B)</p> Signup and view all the answers

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

<p>Troponin is elevated only in myocardial injury, indicating necrosis. (B)</p> Signup and view all the answers

<p>Total ventricular depolarization and repolarization (C)</p> Signup and view all the answers

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

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

<p>AV block indication (A)</p> Signup and view all the answers

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

<p>A single dominant pacemaker controls heart rhythm (D)</p> Signup and view all the answers

<p>Acute myocardial injury (B)</p> Signup and view all the answers

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

<p>Sharp chest pain (C)</p> Signup and view all the answers

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

<p>Involuntary, rhythmic contractions (A)</p> Signup and view all the answers

<p>Fluid accumulation under pressure around the heart (A)</p> Signup and view all the answers

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

<p>Nodes and specialized conducting fibers (A)</p> Signup and view all the answers

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

<p>Closure of the semilunar valves (D)</p> Signup and view all the answers

Using antibiotics to prevent infective endocarditis in high-risk patients before dental procedures that can cause transient bacteremia to protect valves

Muscle contraction in the heart driven by calcium, sarcomeres & t-tubules/SR for Ca+ influx → contraction then Ca+ reuptake for relaxation

Gap junctions and desmosomes that electrically couple cardiac muscle cells for synchronous contraction, and provide mechanical support for a coordinated heartbeat.

Cardiac muscle relies on both extracellular and SR Ca²⁺ for excitation-contraction Coupling; skeletal muscle uses only SR Ca²⁺. Cardiac muscle is involuntary and synchronized by gap junctions, while skeletal muscle is voluntary and independent.

Troponin levels remain normal in angina (chest pain), but increase significantly in a heart attack (myocardial infarction). Elevated troponin indicates myocardial injury due to tissue death.

A series of specialized cardiac cells (SA node, AV node, Bundle of His, bundle branches, Purkinje fibers) that ensure electrical signals are conducted smoothly, leading orderly depolarization and contraction.

Cardiac action potentials are much longer (200-400ms) than neuronal action potentials (1-2ms), with a unique plateau phase from Ca²⁺ influx, while neuronal APs lack a plateau.

Sympathetic (norepinephrine) increases heart rate, AV conduction, and contractility; parasympathetic (acetylcholine) decreases heart rate and AV conduction, with little effect on contractility.

Represents atrial depolarization (contraction).

Time from start of P wave to QRS complex; reflects AV node delay.

Represents ventricular depolarization (contraction).

Early ventricular repolarization phase.

Irregularly irregular rhythm, no distinct P waves. High risk of stroke.

Rapid, wide QRS complexes.

Indicates acute heart attack (transmural infarction).

Faster pacemaker (SA node) suppresses slower pacemakers (AV node etc).

ASD (Atrial Septal Defect) is a heart defect affecting the atria, generally less severe, while VSD (Ventricular Septal Defect) impacts the ventricles, leading to more significant hemodynamic changes.

Striated, branched muscle tissue with intercalated discs, responsible for involuntary and rhythmic contractions of the heart, aided by gap junctions for synchronized beating.

The "lub" sound, caused by the closing of the AV valves at the start of ventricular contraction (systole).

The "dub" sound, caused by the closing of the semilunar valves at the end of ventricular contraction (systole).

Life-threatening condition caused by fluid buildup in the pericardial space, putting pressure on the heart.

The pericardium has two layers: visceral (epicardium) which is part of the heart wall, and parietal (fibrous sac) which surrounds the heart, anchoring it and preventing overexpansion.

Inflammation of the pericardium, often causing sharp chest pain and a friction rub.

Deoxygenated blood flows from the body to the right atrium (RA) through the superior/inferior vena cava and coronary sinus, then to the right ventricle through the tricuspid valve, and finally to the lungs via the pulmonary valve and arteries.