RUSVM Physio Neuro Part 2 Flashcards
What integrates with the incoming information and determine whether action potentials will be produced by the neuron
Dendrites
What are local membrane potentials called? (Learning objective)
Graded Potentials
T/F the cytoplasm of adjacent cells are directly connected by clusters of ion channels called Tight junctions
False- Gap Junctions
What do inhibitory neurotransmitters do? give example
open anion channel
ex = GABA binds to ligand gated chloride channels
what are anion channels opened by? What does it induce?
Opened by inhibitory NT- induce HYPERPOL.
What is the cytoskeleton made up of
neurofilaments and neuroubules
What can neurons not store
Glucose or Oxygen
The action of the NT in the postsynaptic membrane depends on what?
Depends on receptor proteins
Where are graded potentials integrated to generate AP’s (LO)
The trigger zone
What is the most common form of synapses
Chemical synapses
T/F All AP’s generated at the trigger zone are not identical and propagate with strength lost.
False- they are identical and propagate without losing strength
Explain the RELATIVE REFACTORY PERIOD (LO)
Corresponds to the time when voltage gated K channels are close. The AP is inhibited but not blocked. A strong stimuli can shift the membrane potential to the threshold and generate an AP.
What is the threshold potential
the minimal voltage change to trigger an AP (-55mV)
What type of transmission is chemical synapses
Unidirectional transmission
Successive discharges from a single presynaptic terminal summate in the post synaptic neuron is called what?
Temporal summation
What is cation channels opened by? What does it induce?
Opened by excitatory NT- induce DEPOL.
What are the two modes of summation?
Spatial and temporal summation
What is a excitatory postsynaptic potential (LO)
Depolarizing graded potentials- drives the MP toward the threshold. This synapses are called excitatory synapses
T/F Dendritic branching pattern of a neuron can change and may increase or decrease
TRUE
What is the shift of the membrane potential toward more negative called? (LO)
Hyperpolarization
What is the shift of the membrane potential toward more positive called?
DEPOL. - excitatory NT open cation channels
Explain the ABSOLUTE REFACTORY PERIOD (LO)
corresponds to nearly the entire duration of the AP. Represents the time needed for the voltage gated sodium channels to revert from the inactive state to the resting state. AP initiation is completely blocked
Where does ATP for the pump come from?
Intracellular metabolism of glucose and oxygen.
How can neurons be connected to each other?
by Chemical or electrical synapses.
Axonal proteins are synthesized and transported where?
synthesized in the soma and transported to the axon.
T/F Graded Potentials modulate the postsynaptic neuron by shifting the resting membrane potential.
True
T/F Action potential occurs ONLY at the Nodes of Ranvier
True.
What are Ionotropic receptors?
NT receptor that directly gate ion channels - Cation and Anion channels.
Cation -> opened by excitatory NT and induce DEPOL
Anion -> opened by inhibitory NT and induce HYPERPOL.
What are metabotropic receptors?
NT receptors act through second messenger systems- GPCR
Numerous presynaptic axons converge on a postsynaptic neuron generating thousands of what?
Excitatory postsynaptic potentials and inhibitory postsynaptic potentials
What are inhibitory postsynaptic potentials ?
They are hyperpolarizing graded potentials and they are called Inhibitory synapses
What is the site of protein synthesis
Rough ER = Nissl Substance or Nissl body
What type of transmission is electrical synapsrs
bidirectional transmission
What organelles do axons contain
Neurofibrils, neurotubules, small vesicles, lysosomes, mitochondria and enzymes
The axon hillock continues to process graded potentials as long as…
- The sum of all graded potentials stays under the threshold
- The presynaptic changes occur faster than the decay rate of the graded potential in the post synaptic neuron.
T/F Mitochondria are located both in the soma and exons
TRUE
What are dendritic spines
Dendrites are covered with small membranous protusions.
What are the determinants of the membrane potential
- Movement of ions toward a dynamic equilibrium
- Differential permeability of the membrane to diffusion of ions
- Na:K pump
Graded potentials induced by different synapses summate in the postsynaptic neuron are called what?
Spatial summation
