Untitled Quiz

Slows the heart rate by increasing potassium permeability, hyperpolarizing the cells, and lengthening the time to reach the threshold for firing.

Increases heart rate by increasing sodium and calcium permeability, accelerating the membrane's drift toward threshold.

Neurotransmitter released by the parasympathetic nervous system that slows heart rate.

Neurotransmitter released by the sympathetic nervous system that increases heart rate and contractility.

A recording of all action potentials from the heart's nodal and contractile cells at a given time.

A combination of electrodes that measures electrical signals along a line in the body.

An increase in the negativity of the inside of a cell's membrane, making the cell less likely to fire an action potential.

A rapid change in the electrical potential across the membrane of a neuron or muscle cell, essential for signaling.

Are study materials for medical, pre-med, and PA students, focused on high-yield concepts for exams.

The last version of the study notes.

Essential for permanent offline access to the notes, as access may not be perpetual.

Sharing the notes is not permitted to strictly limit distribution.

Allows viewing and access on up to 2 personal devices.

Allows access to notes without an internet connection.

Method to move files from one device to another without re-downloading.

Each purchase comes with a limit on how many downloads the customer is allowed.

The middle mediastinum is located in the inferior mediastinum, extending from the 2nd rib to the 5th intercostal space, anterior to the vertebrae, posterior to the sternum, and flanked by the lungs. It rests on the diaphragm.

Two-thirds of the middle mediastinum's mass is located to the left of the midsternal line.

The pericardium is a protective sac that surrounds the heart, containing lubricating fluid to reduce friction. It anchors the heart and prevents overfilling, ensuring effective pumping.

The outer layer of the pericardium, made of tough connective tissue, protects the heart, anchors it, and prevents overfilling.

The inner layer of the pericardium, composed of two continuous layers: Parietal layer lining the fibrous pericardium and Visceral layer (Epicardium) lining the heart.

The outer layer of the heart, also known as the visceral layer of the serous pericardium.

The muscular layer of the heart responsible for contraction and heart pumping.

The inner lining of the heart chambers, composed of endothelial cells, prevents blood clotting and acts as a barrier between the myocardium and blood.

Special connections between cardiac muscle cells that allow action potentials to travel directly from one cell to another.

Specialized junctions that hold cardiac muscle cells together, providing structural support and allowing for synchronized contraction.

The 'pacemaker' of the heart, naturally generating electrical impulses that regulate the heart rate.

A relay station for electrical signals, delaying the impulse before passing it on to ventricles, allowing for proper chamber filling.

The gradual depolarization of the membrane potential in SA/AV node cells, leading to an action potential.

Muscle cells of the heart that contract in response to electrical signals, primarily responsible for pumping blood.

A period where the membrane potential remains relatively stable, allowing for prolonged contraction in cardiac muscle cells.

The SA node is the primary pacemaker, but other nodal cells can take over if the SA node fails.

A process where the initial influx of calcium into a muscle cell triggers the release of even more calcium from internal stores, amplifying the signal and leading to muscle contraction.

An active transport protein in the cell membrane that uses energy to pump sodium ions out of the cell and potassium ions into the cell, restoring ion balance after an action potential.

A protein that exchanges sodium ions for calcium ions across the cell membrane, removing excess calcium from the cell after a contraction.

A period of time after the absolute refractory period where a stronger-than-normal stimulus can trigger a new action potential. This allows for fine-tuning of heart rate.

Represents the depolarization of the atria, indicating the SA node is functioning properly.

Represents the delay between the SA node and AV node, allowing for atrial contraction.

Represents the depolarization of the ventricles.

Represents the period of ventricular contraction.

Represents the repolarization of the ventricles.

Occurs when the depolarization wavefront moves towards the positive electrode.

Occurs when the depolarization wavefront moves away from the positive electrode.