Muscle Physiology

4.

The Neuromuscular Junction

4.1.

Motor Neuron Components

4.1.1.

4.1.2.

4.1.3.

4.1.4.

4.2.

Motor Unit Concept

4.2.1.

4.2.2.

Functional Significance

4.2.3.

Size Variations

4.3.

Structure of the Neuromuscular Junction

4.3.1.

Presynaptic Terminal

4.3.1.1.

Axon Terminal Structure

4.3.1.2.

Synaptic Vesicles

4.3.1.3.

Calcium Channels

4.3.1.4.

4.3.2.

4.3.2.1.

4.3.2.2.

4.3.2.3.

4.3.3.

Postsynaptic Region

4.3.3.1.

Motor End Plate

4.3.3.2.

Junctional Folds

4.3.3.3.

Acetylcholine Receptors

4.3.3.4.

Acetylcholinesterase

4.4.

Acetylcholine System

4.4.1.

Synthesis of Acetylcholine

4.4.1.1.

Choline Acetyltransferase

4.4.1.2.

Substrate Requirements

4.4.2.

Storage in Synaptic Vesicles

4.4.2.1.

Vesicular Acetylcholine Transporter

4.4.2.2.

Vesicle Recycling

4.4.3.

Nicotinic Acetylcholine Receptors

4.4.3.1.

4.4.3.2.

4.4.3.3.

Ion Selectivity

4.5.

Synaptic Transmission

4.5.1.

Arrival of Action Potential

4.5.2.

4.5.2.1.

Voltage-gated Calcium Channels

4.5.2.2.

Calcium Sensing

4.5.3.

Vesicle Fusion and Exocytosis

4.5.3.1.

4.5.3.2.

Calcium-dependent Release

4.5.4.

Acetylcholine Diffusion

4.5.5.

Receptor Binding

4.5.6.

End-plate Potential Generation

4.5.6.1.

4.5.6.2.

4.5.7.

Muscle Action Potential Initiation

4.5.7.1.

4.5.7.2.

All-or-None Response

4.6.

Signal Termination

4.6.1.

Acetylcholinesterase Function

4.6.1.1.

Enzymatic Hydrolysis

4.6.1.2.

Location and Distribution

4.6.2.

Acetylcholine Removal

4.6.3.

Choline Reuptake

4.6.3.1.

Choline Transporter

4.6.3.2.

Recycling Process

4.7.

Neuromuscular Junction Disorders

4.7.1.

Myasthenia Gravis

4.7.2.

Lambert-Eaton Syndrome

4.7.3.

4.7.4.

Organophosphate Poisoning

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5. Excitation-Contraction Coupling