Which of the following functions is associated with efferent neurons?
A.
Carrying stimulus to the spinal cord and the brain from all other parts of the body
B.
Conducting impulses from sensory neurons to motor neurons
C.
Regulating neuron function
D.
Carrying stimulus away from the brain and spinal cord
The Correct Answer and Explanation is:
The correct answer is D. Carrying stimulus away from the brain and spinal cord.
Explanation:
Efferent neurons, also known as motor neurons, are integral to the nervous system’s functionality. Their primary role is to transmit signals from the central nervous system (CNS) to various effectors throughout the body. Effectors can include muscles and glands that carry out the appropriate responses to stimuli.
Here’s a detailed breakdown of their function:
- Signal Transmission: Efferent neurons carry electrical impulses away from the brain and spinal cord to muscles and glands. For example, when you decide to move your hand, the brain sends a signal through efferent neurons to the muscles in your arm, instructing them to contract and produce movement.
- Motor Pathways: Efferent neurons are part of the motor pathways that control voluntary and involuntary actions. Voluntary movements, such as walking or writing, involve complex pathways from the brain’s motor cortex through the spinal cord and finally to the muscles. Involuntary actions, such as reflexes, involve shorter pathways that do not require conscious thought.
- Role in Reflexes: In reflex arcs, which are automatic responses to stimuli, efferent neurons play a crucial role. For instance, when you touch something hot, sensory neurons send a signal to the spinal cord. The spinal cord then sends an immediate signal back through efferent neurons to the muscles to withdraw the hand, often before the sensation even reaches the brain.
- Distinction from Afferent Neurons: Efferent neurons should be distinguished from afferent neurons, which are responsible for carrying sensory information from the body to the CNS. While afferent neurons are involved in bringing sensory input (such as touch or pain) to the brain, efferent neurons are involved in executing the responses initiated by the brain.
- Regulation and Coordination: By controlling muscle contractions and glandular secretions, efferent neurons help in maintaining homeostasis and enabling adaptive responses to environmental changes.
In summary, efferent neurons are vital for translating the CNS’s commands into actionable responses in the body. Their role in carrying impulses away from the brain and spinal cord ensures that the body can perform necessary actions and maintain physiological balance.