Content Content

Differentiate into:

The Nervous System

Differentiate into:

• Melanocytes
• Schwann cells
• Chromaffin cells of adrenal medulla
• Dorsal root ganglia
• Sympathetic chain ganglia
• Prevertebral sympathetic ganglia,
• Enteric parasympathetic ganglia of the gut (Meissner and Auerbach; CN X)
• Abdominal/pelvic cavity parasympathetic ganglia

Neural Crest cells

The Nervous System

The Nervous System

How Does the Spinal Cord Develop?

The Nervous System

The mantle layer (gray matter) grows asymmetrically so that a dorsal and a ventral mass develops on each side of the midline, the alar and basal plates, respectively

What are the fates of the alar and basal plates?

The Nervous System

What are the fates of the alar and basal plates?

Answer: The alar plate becomes the dorsal horn composed of sensory neurons, and the basal plate becomes the ventral horn composed of motor neurons.

The Nervous System

Answer: The alar plate becomes the dorsal horn composed of sensory neurons, and the basal plate becomes the ventral horn composed of motor neurons.

The Nervous System

MYELINATION OF THE SPINAL CORD

• Oligodendrocytes accomplish myelination in the central nervous system.
• Schwann cells accomplish myelination in the peripheral nervous system.

The Nervous System

The Nervous System

POSITIONAL CHANGES

• At birth the conus medullaris extends to the level of the third lumbar vertebra (L3)
• In adults, the conus medullaris terminates at L1–L2 interspace
• Growth results in the nonneural filum terminale, which anchors the spinal cord to the coccyx.

The Nervous System

Hypophysis

• Anterior lobe (adenohypophysis), pars tuberalis, and pars intermedia develop from Rathke’s pouch which is an ectodermal diverticulum of the primitive mouth cavity (stomodeum)

The Nervous System