Question

What are the functions performed by the three types of neurons? Describe the structure and functions of the three parts of a neuron. (page 277 )

Short answer

In short, the three types of neurons are sensory neurons that gather and transmit sensory information, motor neurons that transmit information from the CNS to muscles, glands, and organs for performing actions, and interneurons that connect other neurons and facilitate communication within the nervous system. Neurons consist of three main parts: the cell body (soma), which contains the nucleus and controls overall function; dendrites, which receive information from other neurons; and the axon, which transmits electrical signals to other neurons or target cells.

Step-by-step solution

Introduction to neurons

Neurons are specialized cells within the nervous system that transmit signals throughout the body. There are three primary types of neurons: sensory neurons, motor neurons, and interneurons. Each type has a specific role in transmitting information within the body.

Explain the functions of sensory neurons

Sensory neurons, also known as afferent neurons, enable the body to respond to various stimuli from the external environment. Their main function is to gather and transmit sensory information from sensory receptors to the central nervous system (CNS). For example, sensory neurons carry information about touch, taste, temperature, and light to the CNS for processing and interpretation.

Explain the functions of motor neurons

Motor neurons, also known as efferent neurons, transmit information from the CNS to the muscles, glands, and organs of the body to perform an action. They are responsible for carrying the response generated by the CNS (in response to sensory input) to the target muscles, glands, or organs. For example, motor neurons send signals to our leg muscles to enable them to contract and move while walking.

Explain the functions of interneurons

Interneurons are the most abundant type of neuron in the nervous system and are mainly found within the CNS. They connect other neurons, acting as a bridge between sensory and motor neurons, and play a crucial role in creating neural circuits for information processing and integration. Interneurons are responsible for facilitating communication between different parts of the nervous system, thus contributing to complex processes such as learning, memory, and decision-making. Now that we have discussed the functions of the three types of neurons, let's move on to the structure and functions of the three parts of a neuron.

Define the structure of a neuron

A neuron typically consists of three main parts: the cell body (soma), dendrites, and the axon.

Describe the cell body (soma)

The cell body, or soma, is the central part of a neuron where the nucleus resides. It contains the neuron's genetic material and controls the overall function of the neuron. The cell body is responsible for generating and maintaining the essential molecules and structures required for proper neuronal functioning.

Describe dendrites

Dendrites are branched projections that extend from the cell body. They function as the primary site for receiving information from other neurons. Dendrites have numerous synapses (connections with other neurons) that allow them to gather inputs from multiple sources. The collected information is then transmitted to the cell body, which integrates the inputs and generates an appropriate response.

Describe the axon

The axon is a long extension that emerges from the cell body and transmits electrical signals, called action potentials, to other neurons or target cells. The end of the axon, known as the axon terminal, forms synapses with other neurons or target cells, enabling the neuronal signal to be transmitted across a small gap called the synaptic cleft. The axon can be insulated with a myelin sheath, which increases the speed and efficiency of signal transmission. In conclusion, the different types of neurons (sensory, motor, and interneurons) play specific roles in facilitating communication within the nervous system. Each neuron, consisting of a cell body, dendrites, and axon, has specific structures and functions that allow it to effectively transmit information within the body.