Video Transcript
Which of the following tables
correctly summarizes the main types of neurons and their functions? (A), which states sensory neurons
carry impulses from the receptors to the relay neurons, relay neurons carry impulses
between sensory and motor neurons, and motor neurons carry impulses from relay
neurons to effectors like muscles and glands. (B), which states sensory neurons
carry impulses from relay neurons to effectors like muscles and glands, relay
neurons carry impulses between sensory and motor neurons, and motor neurons carry
impulses from receptors to relay neurons. (C), which states sensory neurons
carry impulses from relay neurons to motor neurons, relay neurons carry impulses
from the central nervous system to the muscles and glands, and motor neurons carry
impulses from receptors to the central nervous system. (D), which states sensory neurons
carry impulses from receptors to the central nervous system, relay neurons carry
impulses from the central nervous system to the muscles and glands, and motor
neurons carry impulses from relay to sensory neurons.
To answer this question let’s
review the three main types of neurons and their functions.
From the table, we can see that
there are three main types of neurons, which are sensory neurons, motor neurons, and
relay neurons.
Sensory neurons are typically found
in the peripheral nervous system, where they collect sensory information from
receptors about the body and the external environment. The collected sensory information
is then carried towards the central nervous system for processing. The flow of information towards the
central nervous system is also why sensory neurons are called afferent neurons, as
the word afferent is Latin for bringing toward.
Motor neurons, which are also found
in the peripheral nervous system, transmit motor information to the muscles, organs,
and glands. The motor information from the
brain and spinal cord is carried away from the central nervous system to the
effectors likes muscles and glands. This flow of information away the
central nervous system is also why motors neurons are called efferent neurons, since
the word efferent is Latin for carrying away.
Relay neurons are the largest class
of neurons, because it describes any neuron that is not a sensory or motor
neuron. Instead, relay neurons transfer
information between sensory and motor neurons. Since the flow of information in
relay neurons moves between sensory and motor neurons, they’re also called
intermediate neurons or interneurons.
From our review, we can eliminate
certain answer choices. For example, there are only two
tables which correctly describe relay neurons as transferring information between
sensory and motor neurons. Between the two remaining choices,
we can further eliminate one answer choice that incorrectly describes motor neurons
as carrying impulses from receptors to relay neurons.
With this information, we can
identify the correct answer choice. The table that correctly summarizes
the main types of neurons and their functions describes the function of sensory
neurons as carrying impulses from receptors to relay neurons and the function of
relay neurons as carrying impulses between sensory and motor neurons and the
function of motor neurons as carrying impulses from relay neurons to effectors like
muscles and glands.
