Cellular Physiology of Nerve and Muscle

Cellular Physiology of Nerve and Muscle , Fourth Edition offers a state of the art introduction to the basic physical, electrical and chemical principles central to the function of nerve and muscle cells. The text begins with an overview of the origin of electrical membrane potential, then clearly illustrates the cellular physiology of nerve cells and muscle cells. Throughout, this new edition simplifies difficult concepts with accessible models and straightforward descriptions of experimental results.

An all-new introduction to electrical signaling in the nervous system.

Expanded coverage of synaptic transmission and synaptic plasticity.

A quantitative overview of the electrical properties of cells.

New detailed illustrations.

Cellular Physiology of Nerve and Muscle, Fourth Edition offers a state of the art introduction to the basic physical, electrical and chemical principles central to the function of nerve and muscle cells. The text begins with an overview of the origin of electrical membrane potential, then clearly illustrates the cellular physiology of nerve cells and muscle cells. Throughout, this new edition simplifies difficult concepts with accessible models and straightforward descriptions of experimental results.

• An all-new introduction to electrical signaling in the nervous system.

• Expanded coverage of synaptic transmission and synaptic plasticity.

• A quantitative overview of the electrical properties of cells.

• New detailed illustrations.

Gary G. Matthews is the author of Cellular Physiology of Nerve and Muscle, 4th Edition, published by Wiley.

Auteur

Gary G. Matthews is the author of Cellular Physiology of Nerve and Muscle, 4th Edition, published by Wiley.

Texte du rabat
Cellular Physiology of Nerve and Muscle offers a state of the art introduction to the basic physical, electrical, and chemical principles central to the function of nerve and muscle cells. The text begins with an overview of the origin of electrical membrane potential, then clearly illustrates the cellular physiology of nerve cells and muscle cells. Throughout, this new edition simplifies difficult concepts with accessible models and straightforward descriptions of experimental results. The fourth edition of Cellular Physiology of Nerve and Muscle features new material including:

· An all-new introduction to electrical signaling in the nervous system
· Expanded coverage of synaptic transmission and synaptic plasticity
· A quantitative overview of the electrical properties of cells
· New detailed illustrations

Résumé

Cellular Physiology of Nerve and Muscle, Fourth Edition offers a state of the art introduction to the basic physical, electrical and chemical principles central to the function of nerve and muscle cells.

The text begins with an overview of the origin of electrical membrane potential, then clearly illustrates the cellular physiology of nerve cells and muscle cells. Throughout, this new edition simplifies difficult concepts with accessible models and straightforward descriptions of experimental results.

• An all-new introduction to electrical signaling in the nervous system.
• Expanded coverage of synaptic transmission and synaptic plasticity.
• A quantitative overview of the electrical properties of cells.
• New detailed illustrations.

Échantillon de lecture
1

Introduction to Electrical Signaling in the Nervous System

The Patellar Reflex as a Model for Neural Function

To set the stage for discussing the generation and transmission of signals in the nervous system, it will be useful to describe the characteristics of those signals using a simple example: the patellar reflex , also known as the knee-jerk reflex. Figure 1-1 shows the neural circuitry underlying the patellar reflex. Tapping the patellar tendon, which connects the knee cap (patella) to the bones of the lower leg, pulls the knee cap down and stretches the quadriceps muscle at the front of the thigh. Specialized nerve cells ( sensory neurons ) sense the stretch of the muscle and send a signal that travels along the thin fibers of the sensory neurons from the muscle to the spinal cord. In the spinal cord, the sensory signal is received by other neurons, called motor neurons . The motor neurons send nerve fibers back to the quadriceps muscle and command the muscle to contract, which causes the knee joint to extend.

Figure 1-1 A schematic representation of the patellar reflex. The sensory neuron is activated by stretching the thigh muscle. The incoming (afferent) signal is carried to the spinal cord along the nerve fiber of the sensory neuron. In the spinal cord, the sensory neuron activates motor neurons, which in turn send outgoing (efferent) signals along the nerve back to the thigh muscle, causing it to contract.

The reflex loop exemplified by the patellar reflex embodies in a particularly simple way all of the general features that characterize the operation of the nervous system. A sensory stimulus (muscle stretch) is detected, the signal is transmitted rapidly over long distance (to and from the spinal cord), and the information is focally and specifically directed to appropriate targets (the quadriceps motor neurons, in the case of the sensory neurons, and the quadriceps muscle cells, in the case of the motor neurons). The sensory pathway, which carries information into the nervous system, is called the afferent pathway , and the motor output constitutes the efferent pathway . Much of the nervous system is devoted to processing afferent sensory information and then making the proper connections with efferent pathways to ensure that an appropriate response occurs. In the case of the patellar reflex, the reflex loop ensures that passive stretch of the muscle will be automatically opposed by an active contraction, so that muscle length remains constant.
The Cellular Organization of Neurons

Neurons are structurally complex cells, with long fibrous extensions that are specialized to receive and transmit information. This complexity can be appreciated by examining the structure of a motor neuron, shown schematically in Figure 1-2a . The cell body, or soma , of the motor neuron-where the nucleus resides-is only about 20-30 µm in diameter in the case of motor neurons involved in the patellar reflex. The soma is only a small part of the neuron, however, and it gives rise to a tangle of profusely branching processes called dendrites , which can spread out for several millimeters within the spinal cord. The dendrites are specialized to receive signals passed along as the result of the activity of other neurons, such as the sensory neurons of the patellar reflex, and to funnel those signals to the soma. The soma also gives rise to a thin fiber, the axon , that is specialized to transmit signals over long distances. In the case of the motor neuron in the patellar reflex, the axon extends all the way from the spinal cord to the quadriceps muscle, a distance of approximately 1 meter. As shown in Figure 1-2b , the sensory neuron of the patellar reflex is structurally simpler than the motor neuron. Its soma, which is located just outside the spinal cord in the dor

Contenu
Part I: Origin of Electrical Membrane Potential.

1. Introduction to Electrical Signaling in the Nervous System.

The Patellar Reflex as a Model for Neural Function.

The Cellular Organization of Neurons.

Electrical Signals in Neurons.

Transmission between Neurons.

2. Composition of Intracellular and Extracellular Fluids.

Intracellular and Extracellular Fluids.

The Structure of the Plasma Membrane.

Summary.

3. Maintenance of Cell Volume.

Molarity, Molality, and Diffusion of Water.

Osmotic Balance and Cell Volume.

Answers to the Problem of Osmotic Balance.

Tonicity.

Time-Cou…