mmmmmmmmmmmmmmmmmm
CNS Lecture 03rd October
Resting Membrane Potentials
Dr Penny Murphy
Objectives
The student should be able to:
Describe the basic building blocks of the central nervous system.
Explain what a “resting membrane potential” (RMP) is and how it is generated. Include the characteristics of the phospholipid bilayer, leak membrane channels and the diffusion of K+ ions, and the role of the Na+/K+ ATPase pump.
Explain how and why increasing the permeability of the membrane to Na+ ions will affect the membrane potential.
Describe the how changing the permeability of the membrane at one location in a cell can produce a localised change in membrane potential, which in turn can spread over short-distances within that cell.
General Introduction.
The nervous system is made up of two types of cell, neurones (nerve cells) and glia. Neurones generate electrical signals and transmit them to other nerve cells or to muscle / endocrine cells. They communicate with one another at synaptic junctions, usually via the release of a chemical messenger known as a neurotransmitter.
Some nerve cells have a sensory role – they can detect for e.g. pressure, heat or light and generate an electrical signal in response. These cells are referred to as “receptors”, but should not be confused with the “neurotransmitter receptors” covered in a later lecture.
Glia (literally meaning ‘glue cells’) out-number neurones by at least 10:1. They provide vital maintenance and support for the nerve cells. Glial cells that are mentioned in this and the following two lectures include:
Oligodendrocytes, which create the myelin sheaths (electrical insulation) around axons in the central nervous system.
Neurolemmocytes (Schwann cells), which create the myelin sheaths around axons in the peripheral nervous system.
Astrocytes, which control the extracellular environment of nerve cells, for example by removing “used” neurotransmitter molecules.
The nerve cell membrane
Cell
Resting Membrane Potentials
Dr Penny Murphy
Objectives
The student should be able to:
Describe the basic building blocks of the central nervous system.
Explain what a “resting membrane potential” (RMP) is and how it is generated. Include the characteristics of the phospholipid bilayer, leak membrane channels and the diffusion of K+ ions, and the role of the Na+/K+ ATPase pump.
Explain how and why increasing the permeability of the membrane to Na+ ions will affect the membrane potential.
Describe the how changing the permeability of the membrane at one location in a cell can produce a localised change in membrane potential, which in turn can spread over short-distances within that cell.
General Introduction.
The nervous system is made up of two types of cell, neurones (nerve cells) and glia. Neurones generate electrical signals and transmit them to other nerve cells or to muscle / endocrine cells. They communicate with one another at synaptic junctions, usually via the release of a chemical messenger known as a neurotransmitter.
Some nerve cells have a sensory role – they can detect for e.g. pressure, heat or light and generate an electrical signal in response. These cells are referred to as “receptors”, but should not be confused with the “neurotransmitter receptors” covered in a later lecture.
Glia (literally meaning ‘glue cells’) out-number neurones by at least 10:1. They provide vital maintenance and support for the nerve cells. Glial cells that are mentioned in this and the following two lectures include:
Oligodendrocytes, which create the myelin sheaths (electrical insulation) around axons in the central nervous system.
Neurolemmocytes (Schwann cells), which create the myelin sheaths around axons in the peripheral nervous system.
Astrocytes, which control the extracellular environment of nerve cells, for example by removing “used” neurotransmitter molecules.
The nerve cell membrane
Cell