Flashcards in German: Synaptic Communications Deck (33):
What ion is responsible for the resting membrane potential?
If all gates were closed, what would be the resting membrane potential?
IN a resting neuron, what channels are being active?
a slow leak K channel that creates the membrane potential and the NA/K ATPase that maintains the electrochemical gradient.
What does the Nernst equation calculate?
The membrane potential for one specific ion.
What does the goldman equation calculate?
The membrane potential for the entire area with all the ions incorporated.
What is the difference between passive and active current flow?
Passive current flow decays over distance, occurs in cell bodies and axons without channels. active does not decay over distance and occurs only in the axons.
What are the differences between ion channels and transporters?
Ion channels passively move ions through a gradient. Transporters actively move against a gradient.
What are the types of ion transporters?
Ion leakage channels, voltage gated channels, ligand gated channels, physical gated channels.
What does anterograde mean?
Away from the nucleus or cell body.
What are two ways to increase axon conductance?
1. Increase axon caliber2. myelination
What are the myelin-secreting cells in the CNS and PNS?
CNS - oligodendrocytesPNS- Schwann Cells or Neurolemmocytes
What is the area of an axon between two myelin sheaths?
Node of Ranvier
What are the two basic types of neurotransmitters?
1. Small Molecules 2. Neuropeptides
What is glutamate do as a neurotransmitter?
Its the primary excitatory neurotransmitter of the CNS.
What does GABA do as a neurotransmitter?
Its the primary inhibitory neurotransmitter of the CNS.
What does acetylcholine do as a neurotransmitter?
Its used in the PNS at synapse as well as in the sympathetic nervous system of the ANS.
In what 3 pools do synaptic vesicles reside when inside a synapse?
1. Readily Releasable Pool2. Recycling Pool3. Reserve Pool
What does Ca bind to to cause a release of synaptic vesicles?
SNARE proteins (specifically synaptotagmin)
What are the two neurotransmitter receptor types and how do they differ?
1. Inotropic: ligand-gated ion channel (fast)2. Metabotropic: G-protein-coupled receptor (slow)
What is the Hebbian Theory?
The theory that neuronal networks undergo activity-dependent plasticity throughout life.
What is LTP and LTD?
Long Term Potentiation: increase in strength and number of neuronal connections over time.Long Term Depression: Decrease
What are the changes at synaptic terminals that drive neuronal plasticity?
1. number of synaptic vesicle release2. # of receptor density3. Changes in receptor sensitivity and conductance4. Changes in receptor subtype expression5. sprouting new synapses6. Formation of new connections
What are the three neurons in the basic somatosensory circuit?
1st order: mechanosensory neuron to the brainstem.2nd order: brainstem to thalamus3rd order: thalamus to somatosensory cortex.
What are the size of the sensory field determined by?
1. # of neurons innervating the dermatomed2. degree of neuronal arborization
What anatomical type of neuron is a mechanosensory neuron?
How does a mechanosensory neuron work?
Mechanosensory neurons are encapsulated by mechanoreceptor cells. Upon physical stimulation, NA channels are opened. The action potential is NOT initiated in the cell body, it just propagates when threshold is hit.
What type of neuronal termination do nociceptors and thermoreceptors have?
free nerve endings
What are the four cranial nerves that innervate the face and neck?
1. trigeminal nerve (V)2. Glossopharyngeal nerve (IX)3. Vagus nerve (X)4. Facial Nerve (VII)
What are the three different types of pain?
1. Somatic - cutaneous perception2. Visceral - from internal organs that are referred to periphery3. Neuropathic - Damage done to PNS or CNS, perceived as a shocking or burning pain.
What are the four types of nociceptors?
1. Thermal nociceptor (A fibers-fast signal) extreme temps above 45 C and below 5 C.2. Mechanical Nociceptors - extreme changes in pressure or tearing. (A fibers- fat signal)3. Polymodal Nociceptors: Thermal, mechanical and chemical stimuli (C fibers - slow signal due to unmylenation)4. Silent Nociceptors - respond to visceral disorders (A fibers- fast signals)
How does pain signaling differ from a somatosensory pathway?
1st order will synapse in the spinal cord and 2nd order will decussate in the spinal cord. This means that the pain can be gated at the spinal cord.
How is pain referred?
Silent nociceptors synapse onto the same second order neuron as peripheral nociceptor.