Spinal cord

Definition

The spinal cord is a long, tubular structure that extends from the brainstem down the vertebral column, serving as a crucial pathway for transmitting neural signals between the brain and the rest of the body. It plays a vital role in reflex actions, motor control, and sensory processing, connecting peripheral nerves to the central nervous system and facilitating communication throughout the body.

5 Must Know Facts For Your Next Test

1. The spinal cord is divided into segments that correspond to different regions of the body: cervical, thoracic, lumbar, sacral, and coccygeal.
2. It contains both gray matter, which consists of neuron cell bodies, and white matter, composed of myelinated axons that form ascending and descending pathways.
3. Reflex actions mediated by the spinal cord occur without direct involvement from the brain, allowing for quick responses to stimuli.
4. Central pattern generators located within the spinal cord are networks of neurons that produce rhythmic patterns of motor output for activities like walking.
5. Damage to the spinal cord can lead to varying degrees of paralysis or loss of sensation below the injury site, depending on its severity and location.

Review Questions

• How does the structure of the spinal cord support its function in transmitting signals between the brain and body?
  • The spinal cord's structure is essential for its function in signal transmission. It is organized into segments that correspond to specific body areas, allowing for efficient communication with peripheral nerves. The presence of both gray and white matter enables processing and routing of information: gray matter processes sensory input and motor output, while white matter facilitates fast transmission of signals between different regions of the central nervous system.
• Discuss the significance of reflexes mediated by the spinal cord in maintaining bodily functions.
  • Reflexes mediated by the spinal cord are critical for maintaining bodily functions as they allow for rapid responses to potentially harmful stimuli without requiring conscious thought. This swift action is crucial for protection against injury. The reflex arc involves sensory neurons detecting a stimulus and transmitting signals to interneurons within the spinal cord, which then activate motor neurons to elicit a quick response, such as withdrawing a hand from a hot surface.
• Evaluate how central pattern generators in the spinal cord contribute to locomotion and rhythmic movement.
  • Central pattern generators (CPGs) in the spinal cord are vital for coordinating locomotion and other rhythmic movements. These networks of neurons can produce rhythmic outputs without requiring sensory feedback or input from the brain. This intrinsic capability allows organisms to maintain steady gaits while walking or running. Understanding CPGs has implications for rehabilitation strategies in patients with spinal cord injuries, as these circuits may be harnessed to promote recovery of movement patterns.

Related terms

neurons:

The specialized cells that transmit nerve impulses throughout the body, including motor neurons, sensory neurons, and interneurons.

vertebrae: The series of small bones that make up the spine, protecting the spinal cord and providing structural support to the body.

reflex arc:

The neural pathway that mediates a reflex action, typically involving sensory neurons, interneurons in the spinal cord, and motor neurons.