Cardiac Physiology and ECG Interpretation

<p>Requires a trained technician to interpret (D)</p> Signup and view all the answers

<p>60–100 beats per minute (B)</p> Signup and view all the answers

<p>Parasympathetic fibers only innervate the SA and AV nodes (B)</p> Signup and view all the answers

<p>Increases heart rate and force of contraction (D)</p> Signup and view all the answers

<p>Action potentials generated by specialized autorhythmic cells spread through the heart muscle triggering contraction. (D)</p> Signup and view all the answers

<p>Action potentials directly cause muscle contraction by triggering the release of calcium ions. (B)</p> Signup and view all the answers

<p>Echocardiography to visualize heart structure and motion. (C)</p> Signup and view all the answers

<p>Cardiac excitability allows us to understand the physiological mechanisms behind the heart's ability to pump blood. (D)</p> Signup and view all the answers

<p>To act as a pacemaker setting the heart rate (C)</p> Signup and view all the answers

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

<p>50 bpm (D)</p> Signup and view all the answers

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

<p>Under specific pathological conditions (B)</p> Signup and view all the answers

<p>To prevent electrical interference between chambers (C)</p> Signup and view all the answers

<p>Increases heart rate by 20-40 bpm (C)</p> Signup and view all the answers

<p>Parasympathetic nerve activity (B)</p> Signup and view all the answers

<p>Na+ influx (B)</p> Signup and view all the answers

<p>Na+ and Ca2+ (A)</p> Signup and view all the answers

<p>They allow rapid spread of depolarizations between cells. (A)</p> Signup and view all the answers

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

<p>It generates spontaneous action potentials autonomously. (C)</p> Signup and view all the answers

<p>Slow depolarizing phase (A)</p> Signup and view all the answers

<p>It slows down significantly. (B)</p> Signup and view all the answers

<p>Spontaneous depolarization of the SA node (C)</p> Signup and view all the answers

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

<p>Increases cAMP levels (D)</p> Signup and view all the answers

<p>Depolarizes more rapidly (C)</p> Signup and view all the answers

<p>Calcium (L-type) channels (A)</p> Signup and view all the answers

<p>Decreases heart rate (B)</p> Signup and view all the answers

<p>Increases the rate of depolarization (B)</p> Signup and view all the answers

<p>Drifting between -90mV and -55mV (C)</p> Signup and view all the answers

<p>Stimulate heart rate increase during stress (C)</p> Signup and view all the answers

<p>They contribute to the slow depolarization of the pacemaker potential. (A)</p> Signup and view all the answers

<p>They contribute to the slow depolarization of the pacemaker potential. (C)</p> Signup and view all the answers

<p>They are responsible for repolarization. (D)</p> Signup and view all the answers

<p>It is constantly fluctuating due to the activity of the funny current channels (If). (C)</p> Signup and view all the answers

<p>The pacemaker potential is a gradual depolarization that triggers the action potential. (B)</p> Signup and view all the answers

<p>Pacemaker cells are responsible for initiating the heartbeat, while non-pacemaker cells carry the electrical signal throughout the heart. (C)</p> Signup and view all the answers

<p>Calcium ions contribute to both the slow depolarization of the pacemaker potential and the plateau phase of the action potential in non-pacemaker cells. (B)</p> Signup and view all the answers

<p>The atria, specifically the sinoatrial and atrioventricular nodes. (C)</p> Signup and view all the answers

The ability of heart cells to respond to stimuli and generate action potentials.

The process by which heart cells shorten and generate force to pump blood.

A rapid change in electrical charge across a cell membrane that leads to contraction.

A test that records the electrical activity of the heart over time.

The number of times the heart beats in a minute, indicative of cardiac activity.

Na+ causes rapid depolarization in non-pacemaker cardiac cells.

Slow depolarization in pacemaker cells due to Na+ influx.

Ca2+ prolongs action potential duration and creates a plateau phase in cardiac muscle cells.

Ca2+ ions initiate the depolarization phase in pacemaker cells.

Cells that generate spontaneous action potentials, influencing heart rhythm.

The SA node initiates depolarization and sets the heart's pace.

Gap junctions allow depolarizations to spread rapidly between adjacent heart cells.

AV node slows conduction of electrical activity between atria and ventricles.

The primary pacemaker of the heart, setting the rhythm at ~70 bpm.

A secondary pacemaker that routes electrical signals and delays transmission, firing at ~50 bpm.

Conductive fibers that spread depolarization through the ventricles, allowing synchronized contraction.

Controlled by sympathetic and parasympathetic nervous systems, affecting pace of heart beats.

The influence of the vagus nerve that usually slows down heart rate at rest.

Neurotransmitter released by the vagus nerve that slows heart rate by binding to receptors in SA node.

Receptors in the SA node that respond to acetylcholine, controlling heart rate.

Protein channels that allow communication between myocytes, absent in atrial and ventricular syncytia.

Increases heart rate through norepinephrine from sympathetic nerves.

A neurotransmitter that increases heart rate at the SA node.

Receptors on SA node cells that bind NE to increase heart rate.

A molecule that increases PKA activity leading to increased heart cell activity.

The control of heart rate by sympathetic and parasympathetic systems.

Parasympathetic nerves that decrease the SA node rate and heart rate.

Nerves that slow heart rate by affecting SA and AV nodes.

Nerves that increase heart rate and force of contraction.

Sinoatrial node initiates heartbeats and regulates heart rate.

Represents atrial depolarization, the electrical activity of atria before contraction.

Represents ventricular depolarization, indicating ventricles are preparing to contract.

Represents ventricular repolarization, the heart's recovery phase.

Key questions to assess an ECG, including rate, rhythm, and wave presence.

Fast response action potentials in non-pacemaker myocytes, characterized by rapid depolarization.

Pacemaker action potentials from autorhythmic cells, causing spontaneous firing due to unstable resting potential.

Channels that cause unstable resting potential in pacemaker cells, permeable to K+ and Na+.

The critical membrane potential that must be reached to trigger an action potential in pacemaker cells.

The shifts in cell membrane potential during pacemaker and action potentials due to ion movements.

Contractile cells that make up most of the muscle wall, transmitting fast response action potentials.

Locations in the heart where pacemaker cells are found, responsible for initiating signals.