LS 2 Neuron Review Send

LS 2 Neuron Review Send - LS 2: Review Chapter 45; Neurons...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: LS 2: Review Chapter 45; Neurons and Nervous System 1) Nervous system made of billions of neurons, which communicate through Electrical and Chemical signals. Soma-cell body, contains nucleus and most cell organelles. (140mm diameter) Where protein synthesis occurs. Dendrites-extension from soma, receptive sites for chemical signals. Axon- neuron has ONLY 1 axon, generate (axon hillock) and conduct signals away from soma; Abundant microtubules for transport. Also known as Nerve Fibers. Axon Terminals- synapse with target cell. Contain neurotransmitter filled vesicles. Glial Cells- not excitable, do not transmit electrical signal; help in nutrient supply, physical support, consume foreign particles, insulate axons. Axon Hillock : High concentration of VGSC; Integrates signal from dendrites and soma, where Action Potential is initiated. . 1) Oligodendroctes- produce Myelin (the covering for axons) in CNS (brain + spinal cord) Can produce myelin to wrap around multiple axons for insulation. 2) Schwann Cells- produce Myelin in PNS (sensory cells). Produce myelin to rap around 1 axon. 3) Glia include Schwann cells and oligodendrocytes, both of which generate myelin sheets on axons. Glia also include astrocytes , which support neurons metabolically and contribute to the bloodbrain barrier. Microglia , help in immune defense. 4) Nodes of Ranvier : are gaps in myelin sheaths along axon. (high concentration of sodium voltage gated channels) 5) Myelin Speeds Up Action Potential/ Saltatory Conductance : Action potentials do not travel along all axons at the same speed. They travel faster in myelinated (100m/sec) than in nonmyelinated (2m/sec) axons, and in large- diameter axons vs. small diameter axons. Squid has giant axon, but vertebrates use myelin insulation. (200 times smaller diameter) (leaky hose vertebrates use myelin insulation....
View Full Document

This note was uploaded on 10/26/2011 for the course LS 2 taught by Professor Pires during the Spring '08 term at UCLA.

Page1 / 9

LS 2 Neuron Review Send - LS 2: Review Chapter 45; Neurons...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online