Professor Diamond continues her discussion of the nervous system with a diagram of a cross section of a developing spinal cord in which she highlights the ependyma, the mantle layer, the neuronal soma, and the marginal layer. She compares the developing cord to an adult cord and discusses the ventricles, the posterior and anterior horn, and the lateral horn in the thoracic cord. After relating these to the sympathetic division of the automatic nervous system and describing funiculi and fasciculi, she provides an example of a spinal nerve.  Her explanation includes the process of sensory fibers traveling via dorsal root ganglia, interneurons and multipolar neurons, as well as how the polio virus attacks anterior horn cells. She continues by discussing the development of cauda equina, detailing how nerve fibers move from the cord level to the vertebral level through the intervertebral foramen, then building to add the menenges while explaining the importance of the filum terminali. Next, she touches on the dermatome and describes how T2 causes a radiation of pain of the medial side of the left arm during a heart attack before returning to the cord to discussing ascending tracts in the cord and three neurons found in dorsal root ganglia, the posterior horn or medulla, and the thalamus, which carry sensory information to the brain. She provides an example using pain and temperature sensations before showing slides illustrating the concepts discussed throughout lecture as well as pictures of brain-degenerative diseases.