Structure and Function of the Nervous System

 

Cells of the Nervous System

Neurons have three major external features

Box 2.1 The Cutting Edge Embryonic Stem Cells

Characteristics of the cell membrane are critical for neuron function

Glial cells provide vital support for neurons

Box 2.2 Of Special Interest Astrocytes

Electrical Transmission within a Neuron

Ion distribution is responsible for the cell’s resting potential

Local potentials are small, transient changes in membrane potential

Sufficient depolarization at the axon hillock opens voltage-gated Na⁺ channels, producing an action potential

Drugs and poisons alter axon conduction

Organization of the Nervous System

Box 2.3 The Cutting Edge Finding Your Way in the Nervous System

The nervous system comprises the central and peripheral divisions

CNS functioning is dependent on structural features

The CNS has six distinct regions reflecting embryological development

Box 2.4 Of Special Interest Neuroendocrine Response to Stress

The cerebral cortex is divided into four lobes, each having primary, secondary, and tertiary areas

Rat and human brains have many similarities and some differences