What is the integrating and command center of the whole NS?
CNS
What NS responds to the outside (sensory)?
PNS
What does it mean to be touched/affected by a nerve?
Innervated
Most cells are only ____ cells away from a neuron.
3-4
Is afferent or efferent flowing into the integrating center?
afferent
Is afferent sensory or motor?
sensory
Is afferent or efferent flowing out of the integrating center to the organs?
efferent
Is efferent sensory or motor?
motor
What are some examples of effector organs?
skeletal muscles
glands
smooth muscle around arteries, veins, and digestive system
Afferent is (motor/sensory) (output/input) and efferent is (motor/sensory) (output/input).
sensory, input
motor, output
Which nervous system conducts impulses from the CNS to skeletal muscles?
Somatic Nervous System
Which nervous system is an involuntary system?
ANS
Does the Somatic/ANS begin at the Motor/Efferent division?
NO! Begins at CNS.
What are the 2 parts of the ANS?
Sympathetic & Parasympathetic division
What are the cells that regulate the chemical environment around neurons and exchange nutrients, waste, & O2 between neurons and capillaries?
astrocytes
Astrocytes make up ___% of the cells in the brain. The other ____% are _____.
10%
90% is neuroglia
Astrocytes belong to _NS.
CNS
Only a few ____ touch the capillaries directly.
neurons
What is the blood brain barrier? Which cells contribute to it?
The BBB helps prevent neurons from touching blood (which can be toxic to neurons). The astrocytes help contribute to it.
Which cells line the ventricles containing CSF?
Ependymal
Ependymal cells belong to _NS.
CNS
Which cells are responsible for immunity and monitor health and defend neurons?
Microglia cells
Microglia cells belong to _NS.
CNS
These cells form the myelin sheaths of the CNS.
Ogliodendrocytes
These cells form the myelin sheaths of the PNS.
Schwann cells
These cells surround the neuron cells within the ganglia.
Satellite cells.
Satellite cells are part of the _NS.
PNS
Ganglia is a cluster of cell bodies in the _NS.
PNS
Nuclei is the cluster of cell bodies in the _NS.
CNS
A collection of axons in the PNS is a(n) ____.
nerve
A collection of axons in the CNS is the ____.
tract
What are the main messaging system?
Nuerons
Which cell is a connector from one body of stuff to another?
astrocyte
True or false. All neurons cannot touch blood.
False
Which cells are important for memory? What is special about them?
Hippocamus. They can divide.
What are the main components of neurons?
cell body
dendrites
axon
myelin sheath
axon hillock
node of ranvier
Schwann cells
What are the main functions of a neuron?
-never really at rest
-mostly amitotic
-high metabolic rate requiring oxygen and glucose
Action potentials and graded potentials are examples of _____ _____ and are in the ___ phase of mitosis.
electrical impulses; G0
What are the main receptive regions of the neuron?
dedrites
What is the biosynthetic center of the neuron?
cell body
What generates and conducts nerve impulses away from the cell body?
axon
What are some characteristics of myelin sheath?
whitish
fatty
segmented covering
protects
insulates
increases conductivity
What is the trigger zone of the neuron?
axon hillock
What is the forward movement along the axon?
anterograde transmission
What is the movement of going back up the axon?
retrograde transmission
What is the difference between Schwann and oligodendrocytes?
Schwann = singular wrapped in sheath
oligodendrocytes = multiple wrapped in sheath
What is the difference between a myelinated and unmyelinated axon?
An unmyelinated axon is still wrapped but much looser, not as tight.
What does wrapping help with?
guiding the growth of the fibers
What are the 3 structural classes of neurons?
multipolar
bipolar
unipolar
Which of the 3 structural classes of neurons is the most common?
Multipolar
Which of the 3 structural classes of neurons lack a dendritic region?
unipolar
What are the 3 functional classes of neurons?
sensory (afferent)
motor (efferent)
interneurons
Which of the 3 functional classes of neurons is the most common?
Interneurons
What is capable of conduction an action potential?
axon
Structure has to do with ______.
polarity
What are the 3 principles/characteristics of electricity?
voltage
resistance
current
What is the flow of electrical charge from point to point?
current
What is the amount of difference (the space) between one membrane and another?
voltage
What is the hindrance of flow?
resistance
The potential difference is a measure of _____.
polarity
At RMP, the cell is _____ inside and ____ outside with a average voltage of _____.
negative; positive; -70mV
A leaky membrane ion channel is always ___.
open
The membrane ion channel is 75% more leaky to ___ than ___.
K; Na
A gated membrane ion channel is a proetin gate that changes ___ or ___ in response to a certain stimulus.
shape; opens
What are the 3 types of gating?
mechanical
ligand
voltage
All cells are ____ to some degree.
polarized
The membrane is _____ _____ to solutes.
selectively permeable
A voltage of -70 means the cell is negative ____ of the membrane.
inside
A chemical/ligand channel is closed until when?
Until a chemical binds to it.
A voltage membrane is closed until when?
Until the voltage inside/outside of the membrane changes.
Changing from -70 is a means of ______.
communication
The interior of the cell going from -70 to -60 is ______.
depolarization
The interior of the cell going from -70 to -80 is _____.
hyperpolarization
Graded potentials are short-lived, ____ changes in membrane potentials.
local
Where do these differences in voltage take place?
right along the membrane
In the K/Na pump, ___ K go ___ and ___ Na go ___.
3 out; 2 in
More ___ can leak out than ___ can leak in.
K; Na
What causes the Na to flow fast into the cell?
electrical & mechanical gradient
At RMP there is a(n) _____ amount of K going in and K going out.
equal
K gets sucked out because ____.
There is all the positive Na going in.
Depolarization shows a (rise/drop) in the curve and is _PSP.
rise; EPSP
Hyperpolarization shows a (rise/drop) in the curve and is _PSP.
drop; IPSP
Will a weak graded potential still lead to an action potential?
NO
What is graded potential?
Diffusion of an ion down inside of the membrane.
With graded potential, what is the "motion" of the ion?
It rushes in and spreads out along inside.
The membrane becomes positive inside once ___.
enough of the positive ions spread within
Graded potential happens mostly on ____.
dendrites
If a graded potential happens on the axon, it leads to ____. When?
an action potential; immediately
_______ is the principle way neurons communicate.
action potential
In ____, there is a(n) _____ in Na permeability, a(n) _____ in Na permeability, and then a(n) _____ in K permeability.
generation; increase; decrease; increase
What is it when the depolarization of an area leads to the depolarization of the forward adjacent area?
propagation (transmission)
_____ is the outside part of the Schwann cell. It is made of ___.
Neurolemma; fat
What are the 3 properties of a neuron?
excitability
conductive
secretion
What do neurons secrete?
neurotransmitters
There is a(n) ____ increase from rest to activity for muscle cells and a(n) ____ increase from rest to activity for neurons.
30-40x; 50%
What restores the RMP after it has been depolarized?
repolarization
If the membrane voltage does not reach ___, then no action potential occurs.
-55mV
What is the critical minimum for depolarization?
-55
Action potentials are a(n) _____ phenomenon.
all-or-nothing
The slight overshoot once the K channels are open and Nc channels close is called _____.
hyperpolarization
The stimulus intensity is encoded in the _____ of action potentials.
frequency
What is the name of the period of time required so that a neuron can generate another action potential?
refractory period
What are the 4 phases of voltage gated?
1. all gates are closed
2. Na gates open
3. Na gates start to close, K gates start to open
4. Na gates are closed, K gates are open; slight hyperpolarization
In a voltage gated channel, what happens when the threshold (-55mV) is reached?
Na gates open and Na starts to enter
What happens when the Na channels are closing?
K channels are opening and K is leaving the cell
Will the gates respond at -25mV?
yes (depolarization) The gates will open
In the fourth stage of voltage gated channels, what is the slight overshoot?
hyperpolarization
The period of a lack of activity occurs for how long? What is the length traveled?
1-2 minutes; 1 mm of axon length
What is the absolute refractory period?
The period from the opening of Na channels until they begin to reset to original state.
Na is open and Na is entering.
Follows stimulation during which no additional action potential can be evoked.
Absolutely nothing can happen!
What is the relative refractory period?
Follows absolute refractory period.
Interval when a threshold for action potential stimulation is elevated.
Na has returned to resting state, some K is still open (and K is still leaving), repolarization is occurring.
What are the 2 refractory periods (in order)?
absolute & relative
What are the factors that affect conduction velocity? How so?
Size (the bigger the axon, the more conductive)
Myelination (the more myelinated, the more conductive)
What are the 2 methods of conduction?
continuous conduction & saltatory conduction
What is continuous conduction? Is it for myelinated or unmyelinated fibers?
Unmyelinated.
Threshold voltage in trigger zone begins impulse.
Chain reaction (walking slowly and deliberately) of opening of Na channels...adjacent to adjacent to adjacent.
How fast does continuous (impulse) conduction occur?
2 m/s
What is saltatory conduction? Is it for myelinated or unmyelinated fibers?
Myelinated.
Skipping parts to go faster (walking normally).
Skipping from node to node (excessive channels at nodes of ranvier).
How fast does saltatory conduction occur?
120 m/s
Is pain transmission happens down a myelinated or unmyelinated axon?
unmyelinated (takes a while for the pain to register)
Why do large fibers have a higher velocity of nerve signal?
More surface area for signals.
Small, unmyelinated fibers travel at what speed?
0.5 - 2 m/s
Small, myelinated fibers travel at what speed?
3 - 15 m/s
Large, myelinated fibers travel at what speed?
up to 120 m/s
You pull your hand away from a hot stove even before the pain sets in. This is an example of...
myelinated fibers
A junction that mediates information transfer between neurons or between a neuron and an effector cell.
Synapse
What is toward (before) the synapse?
Presynaptic
What is away from (after) the synapse?
Postsynaptic
What have neurons that are electrically coupled via protein channels and allow direct exchange of ions from cell to cell (e.g from one muscle cell to another)?
Electrical synapses
Specialized for release and reception of chemical neurotransmitters
chemical synapses
What are the 3 ways in which neurotransmitter effects are terminated?
degradation
reuptake
diffusion
Prozac is an example of _____ (terminated neurotransmitter effect)
reuptake
______ is the termination of neurotransmitters by enzymes; postsynaptic cell or within the synaptic cleft
degradation
______ is the termination of neurotransmitters by astrocytes or the presynaptic cell
reuptake
______ is the termination of neurotransmitters away from the synapse
diffusion
What are the 3 synaptic regions?
axosomatic (axon-body)
axodendritic (avon-dendrite)
axoaxonic (axon-axon)
____ junctions are important for electrical synapses.
gap
These 2 muscle types are involved in electrical synapse.
smooth & cardiac
What mediate, modulate, and alter graded potentials on the postsynaptic cell? They can be ______ or _____.
neurotransmitters; excitatory or inhibitory
What are the two types of summation be the postsynaptic neuron?
temporal and spatial
Which summation is the response to successive releases of NT?
temporal sumamtion
Which summation is the postsynaptic cell stimulated at the same time by multiple terminals?
spatial summation
When a presynaptic cell is stimulated repeatedly or continuously, enhancing the release of NT.
