Chapter 19, Problem 1.1BGL

Summary Introduction

To label: The figure 19.1

Introduction: The nervous system plays an important role in transmitting the reflexes from the tissues to the brain. The neuron is the functional unit of the nervous system. It consists of cell body, axon, and dendrons. Based on the function, the neurons are classified as sensory neurons, motor neurons, and interneurons. Another classification of neurons include unipolar neurons, bipolar neurons, and multipolar neurons that depend on the structure of the neurons.

Answer to Problem 1.1BGL

Pictorial representation:

Fig1: The components of the reflex arc.

Explanation of Solution

The reflexes are the involuntary, rapid, motor responses to the external stimulus. The nerve impulses are carried from the receptor to the effector through the neural reflex arc pathway. The five components of the reflex arc are sensory receptor, sensory neuron, integrating centre, motor neuron, and the effector. The sensory receptor detects the external stimulus and generates the action potential, which inturn passes through the sensory neuron. The sensory neuron has two parts namely sensory neuron,  cell body, and sensory neuron axon. The sensory neuron is a cell body that conducts the impulse to the sensory neuron axon. This inturn sends the impulse to the integrating centre located on the gray matter of the brain. In the integrating centre, the interneurons synapse with the motor neurons that contain two parts namely motor neuron and motor neuron axon. The motor neuron is a cell body that sends the impulse to the motor neuron axon that inturn sends the impulse to the effector.