Neurons Flashcards
Neuron Components
Dendrite
Axon
Presynaptic terminal
Soma
Dendrite
Receive information from other cells
Axon
Carries output information to presynaptic terminal
Presynaptic Terminal
Transmit information to other cells
Neurotransmitter released
Soma
Cell body
Where neurotransmitter is produced
Bipolar Neuron
Has dendrite and root
Pseudounipolar Neuron
Single projection from soma that has two axons
Peripheral and central axon
Peripheral Axon
Carries information from periphery to soma
Central Axon
Carries information from soma to spinal cord
Multipolar Neuron
Multiple dendrites and single axon
Leak Channel
Always open
Allow diffusion from ions from high to low concentration
No energy needed
Gated Channel
Open in response to stimulus and close when stimulus is removed
Modality-gated Channel
Open in response to specific sensory information (mechanical force, temperature, chemicals)
Ligand-gated Channel
Open in response to neurotransmitter binding to channel receptor
Voltage-gated Channel
Important for release of neurotransmitter and propagation of action potential
Depolarization
Less negative (Excitatory)
Allow action potential transmission
Allow neurotransmitters to be released
Hyperpolarization
More negative (Inhibitory) Lack of transmission
Local Potential
Local change in electrical potential Initial change in membrane potential Spreads short distance Either depolarizes or hyperpolarizes Produced from modality-gated channel or ligand-gated channel
Action Potential
Larger change in electrical potential
Large depolarization regenerated along length of axon
All-or-non principle
Spreads long distances by voltage-gated channels
Transmits info down axon and causes release of neurotransmitter
Temporal Summation
Combined effect of local potentials occurring one after another
Spatial Summation
Combined effect of several small local potentials occurring at same time
Events of Action Potentials
Na+ channels open and Na+ goes in
Na+ channels close
K+ channels open and K+ leaves cell
Absolute Refractory Period
No amount of stimulus will result in action potential
Relative Refractory Period
Stronger than usual stimulus will result in action potential
Nodes of Ranvier
Where saltatory conduction is produced to propagate action potential down axon
Interneuron
Modify information in spinal cord
Relay information to different levels of spinal cord
Convergence
Multiple inputs from several neurons to one single neuron
Divergence
Single neuron branches and synapses on multiple neurons
Glial Cells
Provide structure
Transmit information
Involved in neural development
Repair following brain damage
Macroglia
Astrocytes
Oligodendrocytes
Schwann cells
Astrocytes
Provide structure
Regulate neuronal signalling
Blood-brain barrier
Recovery from injury
Microglia
Phagocytosis
Abnormal activation in several diseases
Presynaptic Terminal
Releases neurotransmitter
Postsynaptic Terminal
Receiving cells
Contains receptors, gland, muscle cell, another neuron
Synaptic Transmission
Action potential reaches presynaptic terminal
Calcium enters
Calcium causes vesicles to move toward cleft
Neurotransmitter released
Neurotranmitter binds to postsynaptic receptors
Membrane channel changes shape and ions enter
Excitatory Postsynaptic Potential
Depolarization
Summation can lead to AP
Inhibitory Postsynaptic Potential
Hyperpolariztion
Decrease chance of AP
Acetylcholine
Most prevalent in PNS
Glutamate
Amino Acid
Primary excitatory neurotransmitter
Glycine
GABA
Amino Acid
Primary inhibitory neurotransmitter
Dopamine
Amine
Loss of dopamine is Parkinson’s
Peptides
Important role in pain perception and modulation
Direct Receptor Effect of Neurotransmitter
Open ligand-gated ion channel
Indirect Receptor Effect of Neurotransmitter
Open ion channel through G-protein
