- Preface
- Introduction
- Part One Main Features of Structure and Function
- 1 Structure of the Neuron and Organization of Nervous Tissue
- 2 Glia
- 3 Neuronal Excitability
- 4 Synaptic Function
- 5 Neurotransmitters and Their Receptors
- 6 Parts of the Nervous System
- 7 The Coverings of the Brain and the Ventricular System
- 8 The Blood Supply of the CNS
- Part Two Development, Aging, and Plasticity
- 9 Prenatal and Postnatal Development
- 10 The Nervous System and Aging
- 11 Restitution of Function after Brain Damage
- Part Three Sensory Systems
- 12 Sensory Receptors in General
- 13 Peripheral Parts of the Somatosensory System
- 14 Central Parts of the Somatosensory System
- 15 Pain
- 16 The Visual System
- 17 The Auditory System
- 18 The Sense of Equilibrium
- 19 Olfaction and Taste
- Part Four Motor Systems
- 20 Motor Systems and Movements in General
- 21 The Peripheral Motor Neurons and Reflexes
- 22 The Motor Cortical Areas and Descending Pathways
- 23 The Basal Ganglia
- 24 The Cerebellum
- 25 Control of Eye Movements
- Part Five The Brain Stem and the Cranial Nerves
- 26 The Reticular Formation: Premotor Networks, Consciousness, and Sleep
- 27 The Cranial Nerves
- Part Six The Autonomic Nervous System
- 28 Visceral Efferent Neurons: The Sympathetic and Parasympathetic Divisions
- 29 Sensory Visceral Neurons and Visceral Reflexes
- 30 The Central Autonomic System: The Hypothalamus
- Part Seven Limbic Structures
- 31 The Amygdala and Other Neuronal Groups with Relation to Emotions
- 32 The Hippocampal Formation: Learning and Memory
- Part Eight The Cerebral Cortex
- 33 The Cerebral Cortex: Intrinsic Organization and Connections
- 34 Functions of the Neocortex
- Literature
- Index
(p. 32) Neuronal Excitability
- Chapter:
- (p. 32) Neuronal Excitability
- Author(s):
Per Brodal
- DOI:
- 10.1093/med/9780190228958.003.0003
Chapter 3 treats neuronal excitability and the conduction of electric impulses in axons. Neuronal excitability depends on a membrane potential that can be altered by neurotransmitters released at synapses. Selectively permeable ion channels and active pumping mechanisms create the membrane potential. Altering the membrane potential creates a current across the membrane. Opening ion channels that are selectively permeable to sodium ions can produce depolarization of the membrane followed by repolarization due to opening of potassium channels. This brief current is called an action potential. The action potential usually arises at the beginning of the axon near the neuronal cell body and propagates along the length of the axon. Arrival at the nerve terminal of an action potential leads to release of neurotransmitter. The action potential moves with much higher velocity in myelinated axons (surrounded by an insulating myelin sheath) than in unmyelinated axons.
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- Preface
- Introduction
- Part One Main Features of Structure and Function
- 1 Structure of the Neuron and Organization of Nervous Tissue
- 2 Glia
- 3 Neuronal Excitability
- 4 Synaptic Function
- 5 Neurotransmitters and Their Receptors
- 6 Parts of the Nervous System
- 7 The Coverings of the Brain and the Ventricular System
- 8 The Blood Supply of the CNS
- Part Two Development, Aging, and Plasticity
- 9 Prenatal and Postnatal Development
- 10 The Nervous System and Aging
- 11 Restitution of Function after Brain Damage
- Part Three Sensory Systems
- 12 Sensory Receptors in General
- 13 Peripheral Parts of the Somatosensory System
- 14 Central Parts of the Somatosensory System
- 15 Pain
- 16 The Visual System
- 17 The Auditory System
- 18 The Sense of Equilibrium
- 19 Olfaction and Taste
- Part Four Motor Systems
- 20 Motor Systems and Movements in General
- 21 The Peripheral Motor Neurons and Reflexes
- 22 The Motor Cortical Areas and Descending Pathways
- 23 The Basal Ganglia
- 24 The Cerebellum
- 25 Control of Eye Movements
- Part Five The Brain Stem and the Cranial Nerves
- 26 The Reticular Formation: Premotor Networks, Consciousness, and Sleep
- 27 The Cranial Nerves
- Part Six The Autonomic Nervous System
- 28 Visceral Efferent Neurons: The Sympathetic and Parasympathetic Divisions
- 29 Sensory Visceral Neurons and Visceral Reflexes
- 30 The Central Autonomic System: The Hypothalamus
- Part Seven Limbic Structures
- 31 The Amygdala and Other Neuronal Groups with Relation to Emotions
- 32 The Hippocampal Formation: Learning and Memory
- Part Eight The Cerebral Cortex
- 33 The Cerebral Cortex: Intrinsic Organization and Connections
- 34 Functions of the Neocortex
- Literature
- Index
