Section 2, Exam 2 Flashcards
Communication that takes place between neurons; electrical energy causes release of chemical, chemical is then released from 1 neuron, crosses synapse and binds with reception on another neuron
Electrochemical communication
What are the two types of synapses?
- Purely electrical
2. Chemical (more common)
Fast axonal transport that goes from cell body to synapse (physiological direction)
Anterograde
True or false;
Axonal transport is fast compared to action potentials
False;
action potentials are faster (2-120 m/s compared to mm/day)
Fast axonal transport that goes from synapse to cell body; moves waste product
Retrograde
What important enzyme is transported via fast axonal transport?
Choline Acetyltransferase
How fast is fast axonal transport? slow axonal transport?
200-300 mm/day (takes 3.5-4.5 days to reach nerve terminal from cell body); 2-8 mm/day
What organelle creates acetlyCoA?
Mitochondria
What transports choline and cholinetransferase?
Vesicles
This represses the formation of ACh receptors throughout muscle fiber?
Gene repressors
Proteins embedded in bilipid membrane; channels that ions pass through; receptors are specific types of these proteins
Transmembrane proteins
Overall, in a resting neuron, is the inside positive or negative relative to the outside?
Negative
Transmembrane protein that permit passage based on transmembrane voltage; voltage causes channels to open; required for action potential
Voltage-gated channels
Transmembrane protein that changes shape when a neurotransmitter binds with it, allowing passage of ions; produces graded potentials
Ligand-gated channels
Where are EPPs produced?
NMJ
Permeability is a property of the ______, not the ion
Membrane
Term for when the voltage gated ion channel is open (excited).
Depolarized
Term for when the voltage gated ion channel is closed (resting).
Polarized
Net positive charge inside cell (relative to outside) to create action potential.
depolarized
Where in the muscle cell membrane are ligand gated channels?
End plate - ONLY (think EPPs)
Postsynaptic graded potential that causes the inside of the cell to become more positive
EPSP
Postsynaptic graded potential that causes the inside of the cell to become more negative
IPSP
Name the neurotransmitters that produce EPSPs
- ACh (also only neurotransmitter responsible for EPPs)
- Norepinephrine
- Glutamate
- Substance P
Name the neurotransmitters that produce IPSPs
- Gamma-aminoButyric Acid (GABA)
2. Glycine
What ion shift causes EPSPs
Na+ influx
What ion shift causes IPSPs
Cl- influx, K+ efflux
Name the 7 general steps to provide an evoked muscle fiber action potential
- AP in motoneuron
- Increased Ca permeability and Ca influx in motoneuron parasympathetic in terminal
- Release of ACh from vesicles into synaptic cleft
- ACh binding with postsynaptic nicotinic receptors on motor end plate
- Increased permeability of endplate to Na+; Na+ influx producing EPP
- EPPs conducted by motor plate to skeletal muscle membrane
- EPP depolarize voltage-gated channels in muscle membrane causing a muscle AP
If pain is present, what kind of graded potential will be produced?
IPSPs; will inhibit voluntary movement
True or False:
When an action potential is produced at a motor endplate, more than one fiber is being triggered.
True
Small releases of ACh when theres no stimulus for release of ACh; no action potential
Spontaneous release
Some energy causes the release of ACh
Evoked release
What drug can block Ca channels? Where does this interference take place?
Magnesium; the membrane of the presynaptic nerve ending
What drug prevents the reuptake of choline after ACh is broken down at NMJ? Where does this interference take place?
Anticholinestrase; the postsynaptic motor end plate
What toxin prevents the packaging of ACh? Where does this interference take place?
Vesamicol; the presynaptic nerve ending
What toxins prevents the release of ACh? Where does this interference take place?
Botulism and black widow venom; the presynaptic nerve terminal
What toxin blocs the binding of ACh to the motor endplate? Where does this interference take place?
Curare; the postsynaptic motor endplate
The _______ is the direct cause of an AP in the membrane of a skeletal m. cell
EPP (end plate potential)
The EPP is the postsynaptic _______ at the NMJ that produces or causes muscle APs.
Graded potential
The ______ are caused in the postsynaptic motor endplate by Ca dependent spontaneous presynaptic release of ACh vesicles from the motoneuron’s nerve endings.
MEPPs (mini end plate potentials)
_________ channels conduct ionic currents that produce EPSPs, IPSPs, MEPPs, and EPPs
Ligand-gated channels
Biological electrical currents carried by ions through the membrane.
Ionic currents
When ions move agains the ________ resistance, the product of ionic current and _________ produce biological voltage or potentials
Membrane resistance; membrane resistance
Potential (mV) = ion current X membrane resistance; V=IR
Where are ligand-gated changes located?
Dendrites and cell body of membranes of neurons, and the motor endplate at the NMJ
When a ligand-gated channel opens, ions will move in the direction of its ________ and its _______
Concentration gradient; electromotive force
What do voltage-gated channels change in the membrane when the membrane potential changes?
Permeability of the membrane to ions (movement of Na+ into the cell is responsible for the upstroke of the action potential
