How would the absolute refractory period be affected if voltage-gated sodium channels remained inactivated?
It would be longer than normal
The small space between the sending neuron and the receiving neuron is the
synaptic cleft
When calcium ions enter the synaptic terminal,
they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.
hen neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron
ion channels in the plasma membrane of the receiving neuron open
If a signal from a sending neuron makes the receiving neuron more negative inside
the receiving neuron is less likely to generate an action potential
How is an action potential propagated along an axon
An influx of sodium ions from the current action potential depolarizes the adjacent area.
Why does the action potential only move away from the cell body
The areas that have had the action potential are refractory to a new action potential
The total amount of neurotransmitter released at the axon terminal is directly related to
the number of action potentials
Neurotransmitter is stored and released from
axon terminals and axon varicosities
The falling phase of the action potential is due primarily to
K+ flow out of the cell only
What stops the rising phase of the action potential?
The Na+ inactivation gate closes
Which glial cell produces myelin in the central nervous system?
Oligodendrocytes
When sodium channels open during an action potential, the opening is caused by
the presence of a positive charge
When comparing action potentials to graded potentials, an/two important distinguishing characteristic/s is/are
graded potentials can undergo summation and the rate of action potentials is limited by the refractory period
Conduction occurs along an axon because
inflow of Na+ triggers the adjacent channels to open.
On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you?
The inside surface of the plasma membrane is much more negatively charged than the outside surface.
During the relative refractory period, an initial threshold-level depolarization is usually not sufficient to trigger an action potential. Why
Some Na+ channels have returned to their resting position and K+ channels are still open, so Na+ entry is offset by K+ loss
What is the definition of an ionotropic receptor?
A receptor that alters ion flow when it binds with its ligand.
metabatropic receptor
receptor that contains a binding site for a nuerotransmitter that is coupled to a G protein
cholinergic receptors
Receptors that mediate responses to acetylcholine; subdivided into nicotinicN, nicotinicM, and muscarinic receptors
adrenergic receptors
Receptors that mediate responses to epinephrine and norepinephrine; subdivided into alpha 1 and 2, beta 1 and 2, and dopamine receptors
amine
compound derived from a single amino acid
amino acid
Compounds with an amino group on one end and a carboxyl group on the other end.
peptides
Chains of amino acids that can function as neurotransmitters or hormones
purines
amp and atp
In a graded potential, what is the effect of cytoplasmic resistance and current leak?
The strength of the signal inside the cell decreases over distance.
a compound that influences a postsynaptic cell's response to a neurotransmitter.
neuromodulator
Repair of damaged neurons can be assisted by certain neurotrophic factors secreted by
schwann cells
What type of conduction takes place in unmyelinated axons?
continuous conduction