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Unformatted text preview: CBNS 116 Lecture 3 - Organizing principles & histology and fine structure of the nervous system ASSIGNMENT: In Nolte read Chapter 1: “Introduction to the Nervous System”. FOR NEXT LECTURE: Read Nolte Chapters 4 & 6, “Meningeal coverings of the brain and spinal cord” and “Blood supply of the brain”. TODAY'S LECTURE: The big picture: Cellular neuroscience is heavily emphasized in the first half of CBNS 106, so Chapter 1 will be an easy review for most of you. However, this will likely be your first introduction to electron micrographs , so be sure to look these over carefully as you read the chapter. Excluded from Chapter 1 is an introduction to the techniques used in histology and electron microscopy, so I have provided an overview of these methods in the lecture notes. Having a basic understanding of histological and EM techniques will be useful preparation for both premedical students and students with interest in neuroscience research. Furthermore, anatomy is studied at both the gross and microscopic levels, and this lecture serves as your primary overview of microscopic anatomy (histology) and fine structure (EM). I. Organizing principles of the CNS: Gray matter vs. white matter [slides 30 - 33]. A. Gray matter is comprised of 2 general cell types: neurons and glia B. Gray matter is generally organized into 3 different types of structures 1. Cerebral cortex- the first 1-2 mm of the surface of the brain 2. Ganglia- collections of neuronal (and glial) cell bodies in the PNS. e.g. dorsal root ganglia, autonomic ganglia (sympathetic and parasympathetic) 3. Nuclei- collections of neuronal (and glial) cell bodies in the CNS. Do not be confused by the misnomer “basal ganglia”. The basal ganglia are collections of neurons in the CNS and are therefore, technically, nuclei. C. White matter is organized into bundles called: 1. Commissures- commissures connect identical structures between each hemisphere. The principal commissures are: 1) the corpus callosum, 2) the anterior commissure, and 3) the posterior commissure. 2. Peripheral nerves (PNS). 3. Other CNS - numerous terms are used to describe fiber bundles in the CNS: a. fasciculus- “little bundle” b. funiculus- “string” c. lemniscus- “ribbon” (bundle tends to be flattened out; e.g. medial lemniscus) d. peduncle- “little foot” (axons funnel down into compact bundle) e. tract e.g. optic tract D. Myelination in the PNS (Schwann cells) and CNS (oligodendrocytes) [slides 34 - 36]. D....
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