Excitable Tissues/Neuron signalling part 2 Flashcards
the larger the diameter of myelin the faster the conduction
true or false
true
Which of these ( myelinated or unmyelinated fibers) is the messengers in digestive tracts at 0.7m/sec
unmyelinated fibers
Are myelinated or unmyelinated fibers the messengers in skeletal muscles at 120m/sec
myelinated
Saltatory conduction uses less energy cos it doesn’t have to bring the ion back
true or false
true
Myelin covers what region?
Axon Regions
Myelin is made up of a combination of
protein fat and lipid
myelin is primarily composed of
Lipids
myelin is formed by ________________ in PNS
Schwann cells
myelin is formed by __________________ in CNS
oligodendrocytes
myelinated fibers create a node of what?
Ranvier
myelinated fibers conduct impulses how many times faster?
50 times faster
Which propagation type is it when impulse jumps over sections of the fiber?
saltatory conduction
Which propagation type has reduced use of the sodium-potassium pump, so less energy is produced?
Saltatory conduction
Action potential in this propagation type spreads along every portion of the membrane. and occurs only in unmyelinated fibers?
Contiguous conduction
which propagation types does each region have to generate its own potential action?
Contiguous conduction
which propagation type is in unmyelinated fibers and which is in myelinated?
Unmyelinated - contiguous conduction
Myelinated - saltatory conduction
Which propagation type uses more energy and which uses less energy?
contiguous conduction uses more energy.
saltatory uses less energy.
What are the two types of action potential propagation?
contiguous and saltatory
The region of the neuron that releases chemical messengers that simultaneously influence other cells with which they come into close association is called?
Axon terminal
The first portion of the axon; the region of the cell body from which the axon starts?
axon hillock
Which part of the neuron is rich in sodium-potassium channel/ions?
Axon hillock
The messaging part of the neuron
Axon
Side branches of axon are called?
collaterals
A button-like structure where action potential stops here
axon terminal
The long skinny part of the neuron
conducting zone
What is the output zone of the neuron?
axon terminals
The neuron trigger zone and its where the action potential starts
axon hillock
The part that conducts action potentials in an undiminishing fashion often over long distances is known as
conduction zone
The part where action potentials are initiated is called
Trigger zone
The part where incoming signals from other neurons are received is called
Input zone
Are dendrites connected to the cell body?
yes
Where is the input zone also known as tree branches and is the location where the impulse is collected by the neuron?
Dendrites
the cell body is 1/10th of the entire neuron/nerve cell
Yes
What holds the nucleus of the neuron?
Cell body
What are the basic part of a neuron
- Dendrites
- Cell bodies
- Axon
Action potentials are propagated from the _______ to the ______
from Axon hillock to Axon terminals
What are the consequences of refractory periods?
- all or no principles
- unidirectional propagation (forward movement) of action potentials
Is a refractory period marked by decreased or increased excitability types?
Decreased
in this refractory period, sodium gates are closed and few potassium channels are still opened
relative
this refractory period allows for a second action potential to be generated with a stronger stimulus
relative
this refractory period spans the last part of repolarization and hyperpolarization phase
Relative
this refractory period spans all of repolarization and depolarization phase
Absolute
Sodium channels are closed and potassium channels are opened in this refractory period
Absolute
which refractory period stops the membrane from making action potential when one action potential is being made?
Absolute
Two types of refractory periods are
Absolute and Relative
The period when the cells won’t allow any action potential to be made backwards
- period of time following an action potential
- when the cell becomes very stubborn
Refractory period
In restoring the concentration gradients which are disrupted by action potential, Sodium(Na) and Potassium(K) which is pumped into ICF and ECF respectively.
Sodium is ECF
Potassium is ICF
what gradually restores the concentration gradients disrupted by the action potentials?
Sodium-potassium pump
Which gate closes at the peak to allow for delayed opening of the potassium channels?
ball and chain gate
when the activation gate of action potential opens, does it allow for an increase or decrease of sodium permeability to reach the peak?
Increase of Sodium (Na)
Does delayed opening of the potassium channel at the peak, allow for full action potential?
Yes
what is the inactivation gate of the action potential?
Ball and chain gate
Which potential change type involves double gating of the sodium channels
Action potentials
Which potential change has the role of a positive feedback cycle that allows it to keep climbing till it reaches the peak?
Action potential
Which is considered as a domino effect, action, or graded potential?
Action potential
When action potential reaches threshold, the flow of Sodium ions into the ICF reverses the membrane potential from -70mV to
+30mV
How many milliseconds does the action potential take in total?
1 millisecond
0.5 to climb up
and
0.5 to climb down
Which potential change does not decrease in strength?
Action potential
Repolarization is the rising or failing phase of action potential?
falling phase
The falling stage of action potential is due to
The efflux of potassium is 300 times more permeable
Depolarization of action potential is due to
permeability of Na+ sodium influx
(sodium na+ is 600 times more permeable)
Is depolarization the rising or failing phase of action potential
Rising phase
Which potential change type has to have a threshold potential of -50mV.
If not what happens?
Action potential
if it’s not at -50mV which is the minimum needed for a full action potential, it will die down and become a graded potential.
What type of potential changes used all the electrical states to create a spike +30(the peak )
Action potential
What channel opens up under the influence of temperature change?
Temperature gated channels
What channel opens up when you apply pressure or touch?
Mechanically gated Channel
What channel opens up under the influence of neurotransmitters eg acetylcholine (Ach)?
Chemically gated channels
In what channel does excited ion movement trigger the gate to open (when there is a change in membrane voltage)
voltage-gated channel
Types of channels for action potential change?
- Voltage-gated channel
- Chemically gated channel
- Mechanically gated channel
- Temperature-gated channels
Heat/cold is an example of what type of channel?
Temperature gated channels