Chapter 2 Flashcards
What are the 2 classes of cells in the nervous system
- Neurons
2. Glia
How many neurons are in the brain
100 billion
True or False:
There are more glial cells than neurons
True
What is the neuron made up of (7)
- Dendrite
- Soma
- Axon hillock
- Axon
- Myelin
- Nodes of Ranvier
- Terminal buttons
Where is the axon hillock located
Part of axon usually attached to cell body
What occurs at the axon hillock
The first place an action potential is generated
What is the presynaptic terminal
Terminal button
What is the synapse
The gap between neurons
What can the synapse also be considered (3)
- Terminal button
- Gap
- Postsynaptic cell
How fast does an action potential travel down the axon
200 mph
Where are bipolar neurons located
The retina
Where are pyramidal neurons located
Hippocampus and cerebral cortex
What are glial cells used for
Neural support
What regulate extracellular fluid, take up extra neurotransmitters, and regulate NT
Astrocytes
Where are the endfeet of astrocytes located
On capillaries
What do astrocytes wrap around
The presynaptic terminals of several axons
True or False:
Microglia suddenly proliferate around damaged areas
True
What do microglia cells do
Remove waste and eat viruses, fungi, and microorganisms
Where are oligodendrocytes located
Only in the CNS
True or False:
Oligodendrocytes can make multiple beads on multiple axons
True
Do oligodendrocytes allow for regrowth
No
Where are schwann cells located
The PNS only
Do schwann cells allow for regrowth
Yes’m
How many myelin beads can one schwann cell make
One
What do radial glial cells do
Help guide the migrating neurons from where they are born to where they end up
What is divergence
A sensory neuron that sends sensory info to many downstream neurons
What is convergence
Many sensory neurons send sensory info to one downstream neuron
What is excited and inhibited during the knee jerk reflex
Excited: Quadricep
Inhibited: Hamstring
What does feed forward inhibition do (2)
- Enhances pathway
2. Inhibits opposing actions
What does feedback inhibition do (2)
- Self regulating
2. Prevents excessive activation
What is the input region of a neuron
Dendrites
What is the conductive region of a neuron
Axon
What is the output region of a neuron
Terminal button
What is the integrative region of a neuron
Axon hillock
What do you compare the charge of the intracellular fluid (cytosol) to
The charge of the extracellular fluid
Can membrane permeability change in a neuron
You knows it!!!
What happens during the patellar tendon reflex when the hammer hits the patellar tendon
NA+ goes into the dendrite
What type of potential is sent to the dendrites
Grade potentials
What is a graded potential
Can be of varying magnitudes and lengths
What can the graded potential cause if it is big enough
An action potential
What does the action potential cause
Depolarization of the axon
True or False:
The axon always depolarizes to the same mV level every time it fire no matter how big the action potential
True
What causes depolarization of the axon
Influx of Na+
When does Na+ level the axon
Immediately
Where is the [Na+] concentration higher intracellular or extracellular
Extracellular
What is all or none
The stimulus is either high enough to cause a reaction which involves the entire neuron or it will not cause any reaction at all
What is located in the synaptic cleft of a synapse
Extracellular fluid
What does NT release cause in the dendrites
Graded potentials
If all sensory stimuli are converted to similar electric impulses or AP how do they not get misinterpreted
There are different connections and pathways that go to different sensory regions in the brain
