Plasma membrane of a muscle cell. It is also referred to as sarcolemma.

Sarcolemma

Cytoplasm of a muscle cell. It is also referred to as sarcoplasm.

Sarcoplasm

The A band is the region of a striated muscle sarcomere that contains myosin thick filaments. In fact, the A band is the entire length of the thick filament of the sarcomere. Its length is approximately 1 μm. The center of the A band is located at the center of the sarcomere (M line).

H zone
I band
M line
Z disk

Electrophysiology is the study of the electrical properties of biological macromolecules, cells, tissues, and organs. Electrical signals such as voltage and/or current are generally measured. Examples include measuring changes in the membrane voltage of excitable cells (e.g., neurons, muscle cells, and some endocrine cells) during an action potential. The current carrried by ions as they permeate the pore of ion channels can also be measured - both at the single-channel level (single-channel current), as well as the macroscopic current resulting from the activity of a population of channels. As another example, electrical measurements may involve recording voltage changes at the surface of the skin that result from the activity of skeletal muscles (electromyogram, EMG), cardiac myocytes (electrocardiogram, ECG), or neurons in the brain (electroencephalogram, EEG).

Lidocaine is a local anesthetic and an antiarrhythmic drug. It is a commonly used local anesthetic for minor surgery and in dental procedures. Lidocaine is also used topically to relieve itching, burning, and pain from skin inflammations.

Lidocaine's mechanism of action is to block fast voltage-gated Na⁺ channels of neurons and cardiac myocytes.

Other names used for lidocaine are xylocaine and lignocaine.

Pharmacological Inhibition of Na⁺ and K⁺ Channels

Lidocaine (Wikipedia)

The component of the electrocardiogram (ECG) that corresponds to the depolarization of atrial myocytes. Atrial depolarization precedes atrial contraction.

QRS complex
T wave

The component of the electrocardiogram (ECG) that corresponds to the depolarization of ventricular myocytes. Ventricular depolarization precedes ventricular contraction.

P wave
T wave

Plasma membrane of a muscle cell. It is also referred to as myolemma.

Myolemma

Cytoplasm of a muscle cell. It is also referred to as myoplasm.

Myoplasm

The Z disk (or Z line) defines the boundaries of a muscle sarcomere. Two adjacent Z disks along the myofibril mark the boundaries of a single sarcomere. The Z disks are the attachment sites for the thin filaments. Therefore, from each Z disk, thin filaments extend to two neighboring sarcomeres. When a muscle fiber contracts, the Z disks of a sarcomere move closer together (i.e., the sarcomere also shortens).

A band
H zone
I band
M line