Mod 11: Neuron Anatomy And Physio Flashcards
What are the two basic types of cells?
Neurons and neurolgia
What are the neurons function?.
Conduct signals in the NS and serve all sensorimotor activities and higher cortical functions
Neuroglia are
Supporting and insulating cells
What do Schwann cells do
Form and lay down the myelin sheath on peripheral nerves and form the axon covering
What are the 3 types of neuroglia in the CNS?
- Oligodendroglia
- Astroglia
- Microglia
What is the oligodendroglia function
Form and lay down myelin sheath
What is the function of Astroglia
Occupy spaces between neural processes in the gray matter and insulate the synapse
What do the microglia function as
Macrophages- remove cell debris
Where is the action potential initiated?
axon hillock
Where do each main axon terminate
Terminates by branching into several terminal processes = telodendron
What does the bouton contain?
Vesicles that contain neurotransmitters substance
- excitatory and inhibitory
Where do each telodendron end
Terminal bouton
Neurons can be classified by what 2 features?.
The number of processes they have and the length of the neuron
What are the 3 types or classes of neurons
- Multipolar neuron
- Bipolar neuron
- Unipolar neuron
Most ____ neurons are found in the brain
Multipolar
The bipolar neuron has 2 processes, the dendrite is the _____process and the axon is the _____ process
Peripheral; central
Which neuron is the ‘T-shaped’ neuron
Unipolar neuron
Neurotransmitters are produced by ____ with in the cell’s neuroplasm
Mitochondria
What is the space that exists between the bouton of one neuron and the cell body, dendrite or axon of another neuron
Synaptic cleft
T/f: neuroaaxonal is the site of contact between axon (bouton) and soma or dendrite of 2nd neuron
False: neurosomatic
The internode is the
Distance between nodes
T/F: The membrane potential in a neuron is about +70mv
False: -70mv
Cell membrane is also polarized at -70mv
Inside the cells there is a high concentration of
Potassium and anions
Outside the cel there is a high concentration of
Sodium ions and chloride ions
T/F: resting cell membrane is somewhat impermeable to potassium but very permeable to sodium ions
False; impermeable to sodium ions and very permeable to potassium
What is an action potential?
The nerve impulse
Can be elicited by nerve fibers by any factor that suddenly increase the permeability of the cell membrane to sodium ions
What are AP’s elicited by
A physical or chemical stimulus
To trigger an AP, the membrane potential must become more positive by ____mv
10
How does the membrane potential become more positive when AP is elicited
Sodium leaks into the cell
The return to the membrane potential to its resting state is called
Repolarization
____ is the initial positive change in membrane potential that occurs in preparation for AP
Depolarization
When does the refractory period occur?
After AP is triggered
What are the two components of the refractory period
- Absolute - new AP can’t be generated; neuron is hyperpolarized and negative
- Relative - a strong stimulus can cause a new AP, membrane not fully repolarized
T/F: AP is an all-or-nothing phenomenon
True, fires or not
What are the two types of neural stimulation
Temporal and spatial
What needs to occur to generate a new AP
An arriving stimulus needs to reach the initial segment (axon of hillock) of the neuron and a greater generator potential need to sum
A ____ stimulus evokes a small potential
Weak
The excitation of the receptor membrane makes the post-synaptic membrane more ____
Positive
What’s the difference between the inhibitory an excitatory post-synaptic potential
Inhibitory prevents a developmental of generator potential, decreasing an new AP
Excitatory generates a local graded response to facilitate a AP
