chapter 3 (part1) Flashcards
what is a neuron?
cells that communicate with the brain and body to form thought and actions
what are the parts of a neuron?
- Dendrites
- Axon
- Myelin
- Nodes of Ranvier
- Nucleus
- Cell body
What are dendrites?
They are extensions of the cell body that receive neurotransmitters from other neurons
What is an axon?
Part of a neuron that delivers messages to other neurons and parts of the body
what is an axon hillock?
Intersection b/w the soma and axon, where the axon begins.
What is an axon terminal
part of the axon that releases the neurotransmitters
what is the soma?
Cell body that controls the metabolic processing of the cell and contains all the organelles
what is the terminal button?
End of the axon terminal where the neurotransmitters are released and stored
What is a synapse?
Space b/w neurons
What is a Presynaptic neuron?
part of a neuron that releases neurotransmitters into the synapse
What is a synapse cleft?
space b/w the ends of the neuron (axon terminal) and the end of a receiving neuron (dendrite).
What are nodes of Ranvier
Gaps in b/w the myelin sheaths that allow ions to change the charge inside
What are myelin sheaths?
Sheaths on the axon that provide insulation for faster transportation of neurotransmitters
What is the route of electricity?
Soma —> Axon hillock —> Axon —> Axon terminal
What is the purpose of the sodium potassium pump?
The maintain a polarized neuron
What is polarization?
When negative ions in the cell cause the neuron to have a negative charge.
When polarization occurs, the cell will release neurotransmitters.
a) True
b) Flase
b) False
What is depolarization?
+ charged cells moving inside the cell to make it positively charged.
When the cell is depolarized, it will release neurotransmitters.
a) True
b) False
a) True
What is the action potential?
It is when the inside of a neuron is positively charged and is able to send neurotransmitters. (depolarization)
What is membrane potential?
It is when the inside of a cell is negatively charged and will not send neurotransmitters. (polarization)
What is hyperpolarization?
Occurs during the refractory period which opens the K+ channels and causes the inside of the cell to be more negatively charged which inc the difficulty for the cell to depolarize again.
When does the resting state occur?
After the refractory period where the cell sits at -70mV
How is a cell activated?
By going over the threshold frequency by the opening of Na+ gated channels allowing Na+ to enter the cell.
Where does polarization and depolarization occur in a neuron?
a) Soma
b) Axon hillock
c) dendrite
d) nodes of Ranvier
d) nodes of Ranvier
How do ions get in and out of the cell?
The change in electrical activity opens the channels for ions to leave or enter the cell
How is the action potential achieved?
a) Cl ions moving out of the cell
b) Na ions moving in the cell
c) K ions moving in the cell
d) a and b
e) a and c
d) a and b
What causes Na+ channels to open?
A positive shift in electrical charge after a few Na+ ions enter the cell
what is “saltatory conduction”?
The spreading of action potentials along myelinated axons from one node of Ranvier to another
Why are hyperpolarized axons less excitable
They require a larger action potential.
What depolarizes an axon?
K+ ions entering the neuron and Na+ leaving
What are the different types of neurotransmitters and what do they do?
Excitatory: inc the probability of a neuron to be electrically active
Inhibitory: dec the probability of a neuron to be electrically active
What are agonists?
Chemicals that come from out of the body that mimics neuron’s that are naturally made from inside the body (endogenous).
What are Antagonists?
Chemicals that come from out of the body that inhibit a neuron from inside the body
what are partial antagonists/agonists?
Chemicals from outside of the body that can partially block, mimic, or enhance an action from a neurotransmitter
Why are Glial cells important?
They provide structural support, bring nutrients, remove waste/dead neurons and speed up electrical impulses
What are efferent axons?
Carry elec impulses away from the CNS to trigger a neuron or hormone
What are afferent neurons?
Carry impulses back to the CNS
What is part of the CNS
Brain and spinal cord
What is part of the PNS
Nerves outside of the cell
What are the two parts of the PNS?
Somatic: voluntary
Autonomic: automatic
What does the somatic NS do?
Controls movement
What are the two parts of the Autonomic NS?
Sympathetic: inc heart rate and breathing
Parasympathetic: command organs to recover, digest, and become sexually aroused
