C J Long
Overview of Topics
Types of Supporting Cells
Circulation in the CNS
- Describe the basic functions performed by supporting cells in the CNS and explain how each is accomplished.
- Discuss the difference between microglia and other supporting cells.
- Discuss the importance of maintaining adequate circulation of blood to the brain.
- Describe the meninges and explain their function.
- Discuss the production, flow, absorption, and function of the cerebrospinal fluid.
- Explain how myelin is formed in the CNS and how this differs from the formation of myelin in the PNS.
Supporting structures function in the CNS by:
- Providing physical support
- Removing degenerating neural tissue
- Forming myelin
- Forming cerebrospinal fluid
- Forming "blood-brain barrier"
Types of supporting cells: Glia ("Glia" means glue)
Protoplasmic astrocytes (star-shaped)
- Surround cell bodies & vessels in CNS
- Offer structural support to tracts in CNS
Oligodendroglia (glia cells) - supporting functions:
- Important in nourishment of neurons
- Form myelin in CNS
Microglia - arise from mesoderm
- Mobile & phagocytic
- Most frequently found with degenerative diseases such as chorea and encephalitis
Ependymal cells - inner walls of ventricles
- Filtering blood to form CSF (choroid plexus)
Schwann sheath cells - form myelin sheath in PNS
- Cytoplasm makes up neurilemma
Arteries--supply blood to body from heart
Capillaries have single cell walls which allow materials in blood plasma to pass out into surrounding tissue & allow waste to enter vascular system
- Route blood to small capillaries
Veins-- return blood to heart
- 15% of the blood passes to the brain
- Glucose is the principle material delivered in neural tissue
- When circulation is blocked, neural tissue is rapidly destroyed (2-3 min)
Cerebrospinal fluid (CSF)
Terms to Know
||Schwann sheath cells
||Foramen of Magendie
||Foramen of Luschka
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