Chapter 12 Nervous System Flashcards
What are the two subdivisions of the Nervous System?
CNS and PNS
Explain the breakdown and the components of the nervous sytem?
In the PNS what are the components of the afferent and effernt pathways?
One axon and multiple dendrites
multipolar neuron
What is the most common neuron in the CNS?
multipolar neuron
Identify this type of neuron
Identify this type of neuron
Identify this type of neuron
one axon and one dendrite
Bipolar neuron
Bipolar neurons can be found where?
Olfactory cells, retina, inner ear
Single process leading away from neurosoma
Unipolar neuron
Unipolar neurons can be found where?
sensory cells from skin and organs to spinal cord
many dendrites but no axon
anaxonic neuron
Where are anaxonic neuorns found?
Retina, brain, and adrenal gland
What are the four types of glia that occur in the CNS?
Form myelin sheaths in CNS that speed signal conduction
Oligodendrocytes
Line internal cavities of the brain; secretes and circulates CSF
Ependymal cells
wander through CNS looking for debris and damage (protective)
microglia
Ependymal cells secrete and circulate ____
CSF
covering brain surface and most nonsynaptic regions of neuron in the gray matter, serving many diverse functions
astrocytes
What is the most abundant glia cell in the CNS?
Astrocytes
What are the cells found in the PNS?
Schwann and Satellite Cells
What are the characteristics of a Schwann cell?
What are the characteristics of a Satellite Cell?
Schwann cells produce a _____
myelin sheath
The speed of the nerve impulse depends on? and how?
What is the slowest and fastest fiber? and where are they located?
A difference in concentration of charged particles between one point and another
Electrical potential
What is the resting membrane potential?
(-) 70 mv
Living cells are ___ and have a ____
polarized and a resting membrane potential
Cells have more __ particles on inside of membrane than outside
negative
A flow of charged particles from one point to another
Electrical current
In the body, currents are movements of __, such as or through channels in the plasma membrane
ions
What is the electrical current function in the cell?
Chloride opens __ potential channels and inhibits ___ and causes ___-
chloride, action potential, hyperpolarization
Explain the build up of the resting membrane potential.
Explain the sodium potassium pump
The sodium potassium pump maintains?
Resting membrane potential
The plasma membrane is ____ at rest there is a difference in _____ across the membrane
polarized, potential
Explain the changes that can be made to the membrane potential
These ion channels will open when a specific ligand binds to the receptor connected to the channel
Ligand-gated ion channels
____can bind and cause opening of certain ion channels in the plasma membrane allowing ions to travel into and out of the cell
ligands
chemicals that bind to a receptor
ligands
The change made in the membrane potential form the ions traveling in and out of the cell
local (or graded) potential
_____ and ___ have an abundance of ligand gated ion channels
dendrites and soma
a dramatic change in membrane polarity produced by voltage gated ion channels
action potential
action potential is a dramatic change in membrane polarity produced by __________
voltage gated ion channels
___ has an abundance of voltage gated ion channels
axon (especially axon hillock)
Voltage gated channels open and close at a specific ____
membrane voltage
If the stimulus makes the condition at the ____ reach the threshold stimulusof _ then an ___ will travel down the whole __
axon hillock, -55mv, action potential, axon
The action potential is measured along the ?
axon
Explain the reaction of the sodium and potassium channel during an action potential
Explain the absolute and relative refractory periods
During an action potential and for a few milliseconds after, it is _____ to stimulate that region of a neuron again
difficult or impossible
Chain reaction continues until the nerve signal reaches the end of the axon
continuous conduction
Unmyelinated fibers use what kind of conduction?
continous conduction
conduct signals with saltatory conduction (signal appears to jump from node to node)
conduction in a myelinated fiber
Myelinated fibers conduct signals with ____
saltatory conduction
contain many voltage gated ion channels
nodes of ranvier
ensure the action potential continues in the correct direct, away from the axon hillock towards the axon terminals
Refractory Period
Explain Synaptic transmission
What are the four major chemical categories neurotransmitters fall into?
molecules that are released when a signal reaches a synaptic knob that binds to a receptor on another cell and alter that cell’s physiology
neurotransmitters
