Fundamental Knowledge Flashcards
4 Components of a Neuron
- Dendrites
- Axon
- Presynaptic Terminal
- Soma/Cell Body
Structure: Receives infromation from other cells
Dendrite
Structure: Carries output information to presynaptic terminal
Axon
Structure: Trasmits infromtion to other cells via the release of NT
Presynaptic Terminals
Structure: Location of NT production
Soma/Cell Body
Neuron Type: Dendritic root and single axon
Bipolar
Neuron Type: single projection from soma that divides into two axons
Bipolar Subclass: Pseudounipolar
Defn: Peripheral axon
Carries information from the periphery to soma
Defn: Central axon
Carries information from soma to spinal cord
Neuron Type: Multiple dendrites with a single axon
Multipolar
Term: Essential for transmission of information
Electrical Potentials
Term: Required for maintaining and producing membrane potentials
Membrane Channels
Channel Type:
- ALWAYS open
- Diffusion from high to low concentrations
- No energy required
Leak Channels
Channel Type:
- Open in response to stimulus
- Close when stimulus removed
Gated Channel
Channel Type:
- Open in response to specific SENSORY information i.e. mechanical force, temperature, chemical
Modality-Gated Channel
Channel Type:
- Open in response to a NT
Ligand-Gated Channel
Channel Type:
- Open in resonse to electrical potential
- Important for NT release and AP propagation
Voltage-Gated Channel
Term: difference in electrical charge across the cell membrane at rest
Resting Membrane Potential
Type of Potential:
- NO net flow of ions
- Excitable/Capable of producing change in ion flow
- Neg 70 mV
Resting Membrane Potential
Structure: Maintains resting membrane potential by moving 3 Na OUT and 2 K IN
Na/K Pump
3 Ways Resting Membrane Potential is Maintained
- Na/K Pump
- Intracellular Anions (too large to diffuse out)
- Leak Channels (passive ion diffusion)
Term: Change in resting potential resulting in the cell becoming excited and LESS negative
Depolarization
Term: Change in resting potential resulting in inhibition and the cell becoming MORE negative
Hyperpolarization
Type of Potential:
- Initial change in membrane potential that can be summed (AP can develop)
- Short distance
- Excitatory or Inhibitory
- Produced by modality/ligand-gated channels on the post-synaptic membrane
Local Potential
Type of Potential
- Larger in electrical potential
- Depolarization repeatedly generated along axon length
- All or none
- Causes release of NT
Action Potential
2 ways local potentials can be summed
- Temporal
- Spatial
Term: Combined effect of local potentials occuring rapidly in step wise summation
Temporal Summation
Term: Combined effec tof several small local potentials occurring at the same time
Spatial summation
Degree of change in membrane potential required to initiate AP
~15 mV
Term: No amount of stimulus will result in AP
Absolute Refractory Period
Term: Stronger than usual stimulus will produce AP
Relative Refractory Period
2 features that result in faster conduction
- Large diameter
- Myelination
Term: Multiple inputs from several neurons termination on a single neuron
Convergence
ex. Hearing; Vision; Touch –> Sensory Association Area in Cortex
Term: A single neuron bracnhes and synapses on muliple neurons
Divergence
ex. Pinprick a Sensory Neurons –> Motor Response; Conscious Pain; Unconscious Pain
5 Functions of Glial Cells
- Provide structure
- Transmit Information
- Involved in Neural Development
- Repair s/p Brain Damage
- Maintain Blood/Brain Barrier
3 Types of Macroglial cells
- Astrocytes (structure, regulate neural signaling, blood/brain barrier, development, recovery)
- Oligodendrocytes (produce myelin in CNS)
- Schwann cells (prodcue myelin in PNS, can take on astrocyte functions)
Disease: Demyelination in the PNS, antibodies attack Schwann cells
Guillain-Barre
Disease: Demyelination in the CNS, antibodies attack oligodendrocytes
Multiple Sclerosis
Structure:
- end of axon
- releases NT
Presynaptic Terminal
Structure:
- Receiving cell
- Contains receptors
- Gland, mm cell, neuron
Post-synaptic Terminal
Post-Synaptic Potential:
- Depolarization
- Summation can lead to AP
- Na+ rushes in
Excitatory Post-Synaptic Potential (EPSP)
Post-Synaptic Potential:
- Hyperpolarization
- Decreases chance of AP
- Cl- rushes in
Inhibitory Post-Synaptic Potential (IPSP)
Pre-Synaptic Influence
- Pre-Synaptic Facilitation =
- Pre-Synaptic Inhibition =
- More NT released
- Less NT released
Most prevalent NT in the PNS
Achetylcholine
2 Main Inhibitory Aminao Acids
- GABA
- Glycine
Main Excitatory Amino Acid
Glutamate
NT: Important in pain perception and modulation
Peptides
