Neuron N euroglia (glia) PNS : Schwann cells S atellite cells CNS : Astrocytes

1. Composition of Nervous Tissue • Neuron • Neuroglia (glia) PNS : Schwann cells Satellite cells CNS :Astrocytes Oligodendrocytes Microglial cells Ependymal cells

2. Glia are different from neurons: 1. Neurons haveTWOkinds of “processes” called axons and dendrites，but Glial cells only haveONE. 2. NeuronsCAN generate action potentials, Glial cellsCANNOT. however, Gliado have a resting potential. 3. NeuronsHAVEsynapses that use neurotransmitters. Glial cells DO NOThave chemical synapses. 4. Neurons DONOTcontinue to divide. Glial cellsDOcontinue to divide.

3. Importance of glial cells in nervous system functionis VASTLY underestimated! • Evidence is mounting: • Nurturing role • Signaling role (Memory?) • Inflammation • Pain • Many more to come!

4. There are two main kinds in PNS Schwann cells（雪旺细胞） Satellite cells（卫星细胞）

6. Schwann cell

7. The Schwann cell making the myelin sheath (M) around the axon (A) was cut at the level of the nucleus (N). E - endoneurium. Scale = 300 nm. (Rat, trigeminal nerve.)

8. Schwann 细胞功能： • 形成周围神经系统的有髓神经纤维的髓鞘 • 合成和分泌多种营养因子、细胞外基质成分和细胞黏附分子。 • 周围神经损伤后的再生和修复

9. Satellite cells

10. There are four main kinds in CNS Astrocytes(星形胶质细胞） Oligodendrocytes(少突胶质细胞） Ependymal cells(室管膜细胞） Microglial cells(小胶质细胞）

12. Astrocytes(AS, 星形胶质细胞）

13. Properties of glial cells • Most numerous cell type in brainConstitute ~30-50% of brain volume • Some astrocytes develop processes with expanded end-feet（终足）that are linked to endothelial cells, or to ependymal cells，et al. • Express GFAP-an intermediate filament protein

14. 分 类 • 突起的形态的不同： 纤维性星形细胞：白质中，突起细长，分支少。 原浆性星形细胞：灰质中，突起粗短，分支多。 • 抗原标记物的不同： 1型星形胶质细胞：GFAP+/A2B5- 2型星形胶质细胞：GFAP+/A2B5+

15. Fibrous astrocyte

16. protoplasmic astrocyte

17. 星形细胞的功能： • 为神经细胞提供支持、隔离的作用 • 合成和分泌多种细胞因子（黏连蛋白，生长因子和营养因子），参与神经损伤后再生和修复；参与神经元的迁移； • 参与血脑屏障的构成 • 参与内环境的稳定：具有多数神经递质的受体，参与神经元及其突触功能的离子、递质和代谢的调节,突触的形成和可塑性

18. 功能：新的观点： • 星形胶质细胞负责大脑信息传送 2007《science》“大脑中与记忆和学习有关的海马区中的星形胶质细胞能够释放一种谷氨酸化学信号，这种信号可以提高神经元间的信号效率” ※ 星形胶质细胞可以让高度兴奋的神经元保持适当 “冷 静”，免受疾病侵袭； ※ 星形胶质细胞能使神经元产生长时间增强反应，使 人学得进、记得牢。 星形胶质细胞与脑组织的神经干细胞密切相关

19. 《nature》美国的两个科研小组报告说:一种名为“神经胶质细胞”的变异神经细胞所分泌的毒素，可导致肌萎缩侧索硬化症(ALS).《nature》美国的两个科研小组报告说:一种名为“神经胶质细胞”的变异神经细胞所分泌的毒素，可导致肌萎缩侧索硬化症(ALS). 肌萎缩侧索硬化症(ALS)

20. end-feet that are linked to endothelial cells 血 脑 屏 障 Blood brainbarrier • 内皮细胞 • 基膜 • 星形胶质细胞

21. BBB

23. Properties of Blood Brain Barriers • Presence of tight junctions between the endothelial cells • One of the notable features of endothelial cells in comparison to other cell is the lack of pinocytic vesicles(胞饮小泡) • Selective permeability to molecules based on their molecular weight and lipid solubility

24. end-feet that are linked to endothelial cells, or to ependymal cells, or to the pia matter

27. AS参与维持中枢神经系统内环境稳定 • Astrocytes can absorb local excess of neurotransmitters, and release metabolic and neuroactive molecules. • Astrocytes can influence neuronal survival and activity through their ability to regulate constituents of the extracellular environment。

28. 1. 参与葡萄糖代谢 normal disease 酵解 葡萄糖 乳糖 葡萄糖 储存糖原

29. 2. 参与脑内谷氨酸的代谢

31. AChBP as a nAChR decoy Nature 411, 261 - 268 (2001) 星形胶质细胞对突触的调节作用

32. Astrocytes • Astrocytes contact virtually every cell component in brain • Other astrocytes (gap junctions) • Ependymal cells • Neurons (somas, processes, synapses) • Oligodendroglia • Capillary endothelial cells

33. 神经系统疾病的关系 • 帕金森病和Huntington舞蹈病：运动障碍性疾病，与星形胶质细胞 产生的某些物质有关。 • Alzheimer病：与细胞中产生过多的淀粉样前体蛋白有关。

34. Oligodendrocytes(少突胶质细胞） • 束间少突胶质细胞 • 血管周少突胶质细胞 • 神经元周少突胶质细胞 • 镀银染色发现突起很少； • 通过特异性的GC单抗做免疫细胞化学标记，则可见少突细胞有很多突起，而且分支很多。 根据在中枢神经系统中的位置和分布：

35. 功 能 • 形成中枢神经系统的髓鞘 • 抑制神经元轴突的生长和再生 （神经突起生长抑制蛋白） • 摄取神经递质，参与神经系统内的吞噬活动等

40. Ependymal cells(室管膜细胞）

41. Ependymal cells

42. Dr Arturo Alvarez-Buylla contends neural stem are astrocytes that lie one layer in from ventricle lining; Dr Jonas Frisen contends that neural stem cells are cells that line ventricles Who are the stem cells of the adult brain?astrocytes vs. ependymal cells Ependymal cells The subventricular zone astrocytes Johansson et al., "Identification of a neural stem cell in the adult mammalian central nervous system," Cell, 96:25-34, 1999. Doetsch et al., "Subventricular zone astrocytes are neural stemcells in the adult mammalian brain," Cell, 97:703-16, 1999.

43. Microglial cells (小胶质细胞）

44. microglia

45. Typical features of neuronophagia, a cluster of microglia around a necrotic neuron, are shown (HE, high power).

46. On the left side of the diagram, cells labeled "B1", "B2", and "B3" represent chronically activated microglial cells. "B3" is a markedly elongated cell, the nucleus in particular having a long, rod-shaped form. This rod cell is classically seen in general paresis (paretic neurosyphilis) but may also be seen in other chronic disease states of the brain.

47. Microglial activation "Al" is a normal resting microglial cell. Under the stimulus of tissue necrosis, the resting microglial cell undergoes hypertrophy and hyperplasia, entering an intermediate phase often referred to as the "pleomorphic microglial response". Transitional forms in this pleomorphic microglial stage would include "A2a" and "A2b". It is important to remember that as soon as the resting microglial cell is activated it becomes an active mobile scavenger cell. If the necrosis is subtotal, the microglial cells may not be stimulated to evolve beyond this "pleomorphic" stage of response. If necrosis is complete, microglia proceed through further transitional forms, as shown on the diagram, to become rounded macrophages, "A6". The latter are also referred to as "compound granular corpuscles" or "gitter cells".

48. 功 能 • 吞噬功能 静止态——反应态小胶质细胞 • 免疫功能 神经元变性——小胶质细胞——表达MHC抗原——呈递给T淋巴细胞——发挥免疫作用

49. Thanks！