Which contains only motor fibers?

Verified step by step guidance

1. Step 1: Understand the concept of motor fibers. Motor fibers are nerve fibers that carry signals from the central nervous system (CNS) to muscles or glands, enabling movement or secretion. They are part of the efferent division of the nervous system.
2. Step 2: Recall the types of nerves in the human body. Nerves can be classified as sensory (containing only sensory fibers), motor (containing only motor fibers), or mixed (containing both sensory and motor fibers).
3. Step 3: Review examples of nerves that are purely motor. For instance, cranial nerves such as the oculomotor nerve (CN III), trochlear nerve (CN IV), and abducens nerve (CN VI) are primarily motor nerves, as they control eye movements.
4. Step 4: Analyze the options provided in the question. Determine which of the listed choices corresponds to nerves that contain only motor fibers based on your knowledge of anatomy and physiology.
5. Step 5: Cross-reference your answer with anatomical resources or textbooks to confirm that the selected nerves are indeed motor-only, ensuring accuracy in your response.

Key Concepts

Motor Fibers

Motor fibers are nerve fibers that transmit signals from the central nervous system to muscles, facilitating movement. They are part of the efferent pathway, which carries commands from the brain and spinal cord to the body's muscles. Understanding the distinction between motor and sensory fibers is crucial for identifying structures that contain only motor fibers.

Nerve Anatomy

Nerve anatomy refers to the structural organization of nerves, including the classification of fibers based on their function. Nerves can be mixed, containing both motor and sensory fibers, or purely motor. Familiarity with the anatomy of peripheral nerves, such as the spinal nerves and cranial nerves, is essential for determining which contain only motor fibers.

Peripheral Nervous System (PNS)

The peripheral nervous system encompasses all the nerves outside the brain and spinal cord, including those that carry motor signals to muscles. It is divided into somatic and autonomic systems, with the somatic system primarily responsible for voluntary movements. Recognizing the components of the PNS helps in identifying specific nerves that are exclusively motor in function.