Neurology 101 Flashcards
What is the CNS?
Brain and spinal cord
Functions as the body’s “control center”
What is the function of the CNS?
Integrates (information)
Coordinates (activity)
What is the function of the PNS?
Connect the body to the CNS
What is the PNS comprised of?
Somatic and autonomic nervous system
What is the somatic nervous system associated with?
Voluntary control of skeletal muscles
What does the autonomic nervous system regulate?
Involuntary, visceral function (HR, RR, digestion)
What is the autonomic nervous system divided into?
Sympathetic nervous system
Parasympathetic nervous system
Where does the sympathetic nervous system begin?
Thoracic/lumbar spine
What does the sympathetic nervous system mediate?
Sympatho-adrenal response
What does the parasympathetic nervous system regulate?
Rest and digest
Feed and breed
Where does the parasympathetic nervous system begin?
Brainstem or sacral spine
What are the three main types of neurons?
Sensory neurons
Motor neurons
Interneurons
What is the neuronal structure composed of?
Soma
Dendrites
Axon
What is the soma?
Central part of the neuron
Contains the nucleus
What is the dendrites?
Branched projections of the soma that function to receive the inputs from other cells
What is the axon?
Carries nerve impulses away from the soma
How many axon are there per soma?
1, but usually branches extensively
What is the axon hillock?
Where axon emerges from soma
Where are the highest density of voltage-dependent sodium channels?
Axon hillock
What are the parts of the axon?
Axon hillock
Axon terminal
What is the function of myelination?
To increase nerve impulse conduction velocity
What is myelin?
Insulating sheath composed of glial cells
What are glial cells in the CNS?
Oligodendrocytes
What are glial cells in the PNS?
Schwann cells
What are the gaps in myelin sheaths?
Nodes of Ranvier
How is the membrane potential maintained?
Sodium-potassium ATPase pump and ion channels
What is the exchange rate for sodium and potassium?
3 sodium cations out for every 2 potassium cations in
What is the net intracellular charge?
Negative
What is the resting state in an action potential?
Na/K pump actively maintains resting potential
Ion channels closed
What is resting membrane potential?
-70
What are the stages of an action potential?
Resting Stimulus Depolarization Repolarization Hyperpolarization Refractory period
What happens to the sodium during depolarization?
Rapid sodium influx (moves down concentration gradient into neurons)
What happens during repolarization?
Once membrane potential reaches 30-40, potassium channels open and potassium leaves the neuron
Sodium channels close (trapped inside)
What happens during hyperpolarization?
Potassium channels close slowly allowing excess potassium to leave the neuron
Membrane potential falls below resting potential
What happens during the refractory period
Na/K pump works to re-establish resting potential
If an axon was myelinated axons, where does the action potential occur?
Nodes of Ranvier
What is synaptic neurotransmission?
What happens when the action potential reaches the axon terminal
What is the primary means by which neurons communicate with target cells?
Synaptic neurotransmission
How are classical neurotransmitters released into the synaptic cleft?
Synthesized in the presynaptic region of the axon terminal, stored in vesicles, and released into the synaptic cleft
How do neurotransmitters modulate the function of postsynaptic cells?
By binding to receptors
What are the two major subtypes of neurotransmitter receptors?
Ionotropic
Metabotrophic
What do ionotrophic receptors do?
Neurotransmitter engagement results in the direct opening of ion channels
What do metabotrophic receptors do?
Interact with G proteins, stimulating production of second messengers and activating protein kinases to indirectly result in the opening/closing of ion channels
Which neurotransmitter receptors are the fastest?
Ionotrophic
How are neurotransmitters removed from the synaptic cleft?
Reuptake into the presynaptic neuron
Diffusion away from the synaptic cleft
Enzymatic inactivation
What is a neural circuit?
A functional entity of interconnected neurons that utilizes feedback mechanisms to regulate its own activity
What is a neural circuit composed of?
Excitatory and inhibitory neurons
Where does neuronal excitation most commonly occur?
Axodendritic synpases
Where does neuronal inhibition most commonly occur?
Axosomatic synapses
Which types of AA neurotransmitters are excitatory?
Glutamate
Aspartate
Which types of AA neurotransmitters are inhibitory?
Glycine
GABA
Serine
What are the peptide neurotransmitters?
Substance P
Somatostatin
What are the monoamine neurotransmitters?
Dopamine
Histamine
Serotonin
Epinephrine
What are the gasotransmitters?
Nitric oxide
