Question | Answer |
What are the regions of the developing spinal cord? | neuroepithelial, mantle, marginal |
What does the neuroepithelial zone develop into? | all spinal neurons and some support cells |
What does the mantle develop into? | Neuroblast cells - alar and basal plates |
What does the marginal zone develop into? | White matter - anterior |
Where are sensory cell bodies located? | alar plates --> posterior horn |
Where are motor cell bodies located? | basal plates --> anterior horn |
Where is the intermediate horn located? | between the anterior and posterior horn (sympathetic cells) (ANS) |
Roots develop from __________. | axons |
What does the alar plate contain? | posterior horn - sensory neurons |
What does the basal plate contain? | Anterior horn - motor neurons |
What does the intermediate horn contain? | Sympathetic cells (ANS) |
Where are spinal ganglia cells derived from? | Neural crest |
What do spinal ganglia contain? | sensory root axons to dorsal horn |
What do anterior horn cells contain? | Motor root axons to myotome |
What does a dermatome innervate? | Skin |
What does a myotome innervate? | Skeletal muscle |
What does a sclerotome innervate? | Connective tissue |
What is the C3 dermatome landmark? | Neck |
What is the T4 dermatome landmark? | Nipple |
What is the T10 dermatome landmark? | Umbilicus |
What is the L1 dermatome landmark? | inguinal line |
What is the C8 dermatome landmark? | 5th digit of the hand |
What is the C6 dermatome landmark? | Pollex |
What is the L4 dermatome landmark? | Knee |
What is the L5 dermatome landmark? | Anterior ankle and foot |
What is the S2 dermatome landmark? | Posterior lower limb |
Where do the nerves that go through the anterior ramus go? | Hypomere |
What does the hypomere consist of? | Skin everywhere but midline of back, and hypaxial (extrinsic) muscles |
Where do the nerves that go through the posterior root go? | Epimere |
What does the epimere consist of? | skin along the midline of back (to costal angle) and to epaxial (intrinsic) back muscles |
How does development of the sclerotome occur? | Resegmentation to allow for gap for axon. |
How many sclerotome segments is each vertebrae made of? | |
What does sclerotomal mesenchyme surround, and what does it become? | neural tube and notochord. Becomes vertebrae and ribs |
What does the mesenchyme condense into? | Cartilage --> bone |
What is the last part of the vertebrae to form? | spinous process |
What happens when the spinous process doesn't form? | Spina bifida |
What is the spina bifida characterized by incomplete formation with usually no adverse effects? Hairs will form over location. | Spina bifida occulta |
What is the spina bifida characterized by the development of herniation without spinal cord displacement? | Meningocele |
What is the spina bifida where the spinal cord herniates into subarachnoid space? | Meningomyelocele |
What is the fatal form of spina bifida involving folded neural tissue? Fetus usually doesn't come to term. | Rachischisis |
The notochord leaves no trace, except as the _______ _________. | nucleus pulposus |
The sclerotomal mesenchyme becomes the __________. | vertebra |
The nucleus pulposus is surrounded by a ring of fibrocartilage called the ___________ __________. | anulus fibrosus |
In the embryo, where does the spinal cord end? | Full length of vertebral canal |
At 6 months gestation, where does the spinal cord end? | S1 |
In the newborn, where does the spinal cord end? | L2-L3 |
Over the age of 2, where does the spinal cord end? | L1-L2 |
Vertebral body T12 is in close association with the _________ _________ cord segments | lower lumbar |
Vertebral body L1 is in close association with all ___________ spinal cord segments | sacral |