Spinal cord
In this lesson, we'll learn about the spinal cord, a critical structure that links the brain to the body. The spinal cord carries information that supports sensation, movement, and reflexes, among other things.
1) Start with these videos:
2) Then, read this article: Know Your Brain - Spinal Cord
3) Finally, answer these questions to test your understanding:
1. What is the name for the extension of the meninges that extends from the end of the spinal cord to the tailbone and helps anchor the cord in place?
- A. cauda equina
- B. filum terminale
- C. dorsal root ganglion
- D. conus medullaris
Show Answer
Correct answer: B
An extension of the meninges called the filum terminale extends from the end of the spinal cord to the tailbone to anchor the cord in place.
2. If a sample of cerebrospinal fluid is needed, from which region of the spinal cord is it typically obtained from?
- A. cervical
- B. thoracic
- C. lumbar
- D. sacral
Show Answer
Correct answer: C
A sample of cerebrospinal fluid (CSF) is typically obtained from the lumbar region of the spine, below the end of the spinal cord (usually between L3–L4 or L4–L5). This area contains the lumbar cistern, which is filled with CSF but below the end of the spinal cord, making it a safe location to insert a needle without risking injury to the spinal cord.
3. The spinal cord is made up of how many segments?
- A. 12
- B. 26
- C. 31
- D. 48
Show Answer
Correct answer: C
The spinal cord has 31 segments, each giving rise to a pair of spinal nerves. There are: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal segments.
4. The cell bodies of sensory neurons that enter the spinal cord are located in which structure below?
- A. dorsal root ganglion
- B. ventral horn
- C. dorsal horn
- D. ventral root ganglion
Show Answer
Correct answer: A
Neurons carrying sensory information enter the back of the spinal cord as dorsal rootlets, which all emerge from a single dorsal root. The cell bodies of these sensory neurons are contained in a cluster of cell bodies called a dorsal root ganglion.
5. Which of the following accurately describes the white matter of the spinal cord?
- A. it primarily consists of neuronal cell bodies involved in spinal reflexes
- B. it primarily contains ascending sensory tracts and descending motor tracts
- C. it is the primary site of neurotransmitter release between spinal neurons
- D. it primarily contains clusters of interneurons responsible for local processing
Show Answer
Correct answer: B
The white matter of the spinal cord consists of bundles of ascending and descending fibers that carry sensory information to the brain and motor information to the body, respectively.
