Exam 2 Flashcards
define nerves
a tissue; collections of neurons and associated cells (glial cells)
define neurons
excitable cells capable of receiving input stimuli from other cells (or the environment), integrating the signal, transmitting it long distances and relaying the signal to a downstream cell
parts of the Central Nervous System (CNS)
- brain and spinal cord
- cerebral spinal fluid
parts of the Peripheral Nervous System (PNS)
- nerves
- afferent and efferent divisions
Afferent Division
transmission of signal to the central nervous system from sensory and visceral stimuli
Efferent Division
transmission of signals to respond to the original stimulus (voluntary or involuntary)
difference between neurons and nerves
neurons are the cells responsible for the actual transmission signal. nerves are the main tissues involves with receiving and sending signals (collection of neurons and glial cells).
glial cells
non-neuronal cells that support or protect neurons
examples of glial cells
- Schwann cells
- Oligodendrocytes
- Asctocytes
- Microglial
microglial cell
immune cell (glial cell)
asctocytes
encases vasculature and keeps neurons close to blood vessels, homeostasis (glial cell)
Schwann cell
myelinated neurons in PNS (glial cell)
Satellite cell (neural tissue)
extra support and protection in PNS (glial cell)
oligodendrocytes
myelinated CNS axons (glial cell)
ependymal cells
produce cerebral spinal fluid (CNS glial cell)
Efferent branch division
somatic and autonomic nervous system
somatic nervous system
controls motor neurons (skeletal muscle)
autonomic nervous system division
- sympathetic
- parasympathetic
- enteric
sympathetic nervous system
fight or flight response
parasympathetic nervous system
rest and digest response
4 structural regions of neurons
- dendrites
- soma (cell body)
- axon
- synapses
dendrites
major site of synaptic input from other neurons
soma
cell body of a neuron, major site of integration of synaptic potentials
axon
conduction component of a neuron, can be very very long
synapses
the output of a neuron, can alter activities of other cells
presynaptic
passing the signal
post synaptic
recipient of the signal
multipolar neuron
main type, multiple poles from the cell body
bipolar neuron
2 poles coming out of the cell body
unipolar/pseudounipolar neuron
singular branched neuron
PNS glial cells
- Schwann cells
- satellite cells
gray matter
dense collection of cell bodies
white matter
more axonal tracks (myelinated axons are fatty making it have a lighter appearance)
fascicle (nerve)
many axons bundled together in connective tissue
endonerium
connective tissue around the individual axon
(endo=inside)
perineurium/perimysium
connective tissue around a fascicle
epinerium
connective tissue around the entire nerve
describe the organization of a nerve
a nerve consists of a group of fascicles enclosed by a connective tissue covering (axon, covered by myelin sheath, covered by endonerium, all axons packed into a fascicle, faciscle covered by perineurim, multiple fascicles packed together and covered by epinerium)
what does it mean to be excitable?
excitable cells can undergo rapid changes in their membrane potentials
membrane potential
the separation of charges across a plasma membrane
average membrane potential
-70mV
is the inside the cell more negative or positive when there is a membrane potential?
negative charges
is the outside the cell more negative or positive when there is a membrane potential?
positive charges
the greater the concentration gradient, the _______________ the diffusion
more rapid
the concentration gradient is particularly important for determining the ________________________
rate of ion movement
electrolytes and polar solutes can ONLY move through the membrane IF ______________
their channels and transporters allow
how do electron gradients occur?
from concentration gradients when they are separated by selectively permeable membrane (contributes to membrane potential)
Is Na more concentrated on the inside or outside the cell?
outside the cell
Is K more concentrated on the inside or outside the cell?
inside the cell
electro-chemical gradients
movement of ions across the membrane is dependent on concentration gradient AND the charge across a membrane
membrane potential is established primarily by the relatively leakiness of which ions?
Na and K
How is the average membrane potential maintained?
Na/K ATPase pumps
(3 Na out of the cell, 2 K into the cell)
K+ is ________ times more permeable than Na
25
leaky ion channels
open all the time
gated ion channels
induced to open
sensory input
sensory receptors detect some sort of stimuli
integration
nervous system processes the sensory input and decides what should be done about it
motor output
the response that occurs when your nervous system activates certain parts of your body
2 main parts of the nervous system
- central nervous system
- peripheral nervous system
what is a greater make up in the nervous system; neurons or glial cells?
glial cells (10:1)
3 things all neurons have in common
- some of the longest lived cells in the body
- are irreplaceable
- high metabolic rate (25% of calories per day are consumed by the brain activity)
role of an axon
transmit electrical impulses away from the body to other cells
sensory neurons
transmit impulses from sensory receptors to the CNS (afferent neurons) ex=unipolar neuron
motor neurons
impulse moves from CNS to the rest of the body (efferent neurons) ex=mostly multipolar neuron
interneurons
impulse moves between sensory and motor neurons (mostly multipolar neurons)
somatic nervous system
carries motor and sensory information, responsible for voluntary movement, processes external stimuli (hearing, touch, sight)
primary reason a membrane potential forms
due to excess outflow of K+ relative to the inflow of Na+
graded potential
localized changes in a cells membrane potential
can graded potential vary in magnitude?
YES, the potential change is proportional to the signal
(weak signal=minor change, strong signal=major change)
in graded potentials, the more neurotransmitters bound the _____________ the amount of local ion movement across the membrane
greater
can graded potentials be hyperpolarized or depolarized?
yes
depolarization
membrane potential is less negative (more positive)
hyperpolarization
membrane potential is more negative
in a graded potential, the magnitude __________ with distance from the site of origin
diminishes
where do graded potentials occur?
dendrites and soma
the size and duration of membrane potentials is determined by _________________________________
the size and duration of inputs
excitatory inputs
increase positive charges, bring closer to threshold, depolarize
inhibitory inputs
increase negative charges, further away from threshold, hyper polarize
in a graded potential, if there is a stronger stimulus it will release more neurotransmitters which will open more ion channels causing a greater change to the _____________________
membrane potential
threshold value
the membrane potential level that will induce an action potential
how does graded potential spread?
passive current flow
define passive current flow
ions flow between the active area to the inactive areas around it to spread, when the receptor closes the spread will stop
decremental
current flow dissipates from the original source
is graded potential decremental?
YES
summation in post-synaptic (graded) potentials
graded potentials in neurons can enhance or counteract one another id the occur nearly simultaneously or if repeated stimulations arrive in rapid sequence
temporal summation
repeated signals are capable of having a more pronounced effect than the individual signal alone
what does temporal summation look like on a graph?
the original signal gets a larger signal added onto it
spatial summation
stimulation occurs at the same time in different parts of the neuron
what does spatial summation look like on a graph?
- will either combine the signals to create just one larger one
- cancels out the signal completely (excitatory + inhibitory)
if summation (additive depolarization) occurs to reach threshold value an ____________________ will occur
action potential
axon hillock
where the initiation of an action potential occurs in an axon (where the soma and axon connect)
average threshold value
-55 mV
it is the _________________ of multiple graded potentials that can initiate an action potential
cummulative action
action potential
large charges in the distribution of charges across a membrane that occurs rapidly, but last a short amount of time
how long is an action potential?
1-2 ms
are action potential decremental?
NO - the intensity of the signal will be the exact same throughout the entire axon
what does it mean that the action potential is an all or nothing phenomenon?
if threshold is reached an action potential will occur with the same frequency, if threshold is not reached it will not occur
explosive __________________ takes place at threshold
depolarization
repolarization
occurs after depolarization, makes the membrane potential more negative
rapid changes in the membrane potential from a neuron reaching threshold is from the sequential opening and closing of which voltage gated ion channels?
Na and K
what ion depolarizes the membrane potential?
Na+ influx
what ion causes repolarization of a membrane potential?
K+ efflux
which voltage gated ion channel opens at threshold?
Na channels
when are Na+ channels INACTIVATED during and action potential?
the peak of the action potential
what is the difference between the K and Na channels?
Na is faster and more complicates (can inactivate) while K is much slower
when do the voltage gated K channels finally open?
peak of an action potential
what causes hyperpolarization?
the K channels are slow, so they close past the average membrane potential causing the membrane potential to become more negative
resting membrane potential: Na and K voltage gated channels
- Na+ = closed
- K+ = closed
rising phase: Na and K voltage gated channels
- Na+ = open
- K+ = closed
falling phase: Na and K voltage gated channels
- Na+ = inactivated
- K+ = open
Pk or Pna meaning
the permeability of the ions through the membrane
what reestablished and maintains the membrane potential after hyperpolarization of an action potential?
Na/K ATPase
absolute refractory period
period of time when another action potential can NOT be generated (Na+ channels are inactive and cannot be opened)
relative refractory period
an action potential can be generated but it requires a stronger than normal stimuli
why is propagation of an action potential in one direction?
Na channels need time to recover so it cannot go backwards.
The action potential at one location on an axon initiates an action potential at a neighboring location, by repeating this process, a signal can travel longdistances (e.g. 1m) along an axon without any decrease in amplitude.
myelin sheaths
layers of cell membranes from neuron-associated cells that are wrapped around the axon
how do myelin sheaths generally help neurons?
their presence supports and helps propagate action potentials moving down the axon
unmyelinated axons
in the PNS, Schwaan cells will support the axon but there will be no insulating myelin sheath
action potentail propogation in unmyelinated axons
a series of rolling action potentials that occur down the action potential
saltatory propagation
action potentail propogation in myelinated axons
how does myelinated action potential differ from unmyelinated?
- myelinated axons have a faster conduction velocity then unmyelinated axons
- action potential occurs between the nodes
nodes of ranvier
space between myelin sheath, where the voltage gated ion channels are located
action potential conduction velocity is affected by
- myelination
- axon diameter
how does axon diameter affect conduction velocity?
the larger the diameter of the axon, the faster the conduction velocity
GP vs AP: can be depolarizing and hyperpolarizing
graded potential
GP vs AP: always lead to depolarization of membrane and reversal of the membrane potential.
action potential
GP vs AP: Amplitude is proportional to the strength of the stimulus.
graded potential
GP vs AP: Amplitude is all-or-none; strength of the stimulus is coded in the frequency
action potential
GP vs AP: small amplitude
graded potential
GP vs AP: large amplitude (about 100 mV)
action potential
GP vs AP: duration of few ms to sec
graded potential
GP vs AP: short duration of 3-5 ms
action potential
GP vs AP: Ion channels responsible for potentials may be ligand-gated, mechanosensitive, or temperature sensitive channels, or may be channels that are gated by cytoplasmic signaling molecules.
graded potential
GP vs AP: Voltage-gated Na+ and voltage-gated K+ channels are responsible for the neuronal action potential.
action potential
GP vs AP: The ions involved are usually Na+, K+, or Cl−
graded potential
GP vs AP: The ions involved are Na+ and K+
action potential
GP vs AP: No refractory period
graded potential
GP vs AP: Absolute and relative refractory periods are important aspects
action potential
GP vs AP: can be summed over time (temporal summation) and across space (spatial summation).
graded potential
GP vs AP: Summation is not possible (due to the all-or-
none nature, and the presence of refractory periods).
action potential
GP vs AP: travel by passive spread (electrotonic spread) to neighboring membrane regions.
graded potential
GP vs AP: propagation to neighboring membrane regions is characterized by regeneration of a new potential at every point along the way.
action potential
GP vs AP: decremental
graded potential
GP vs AP: non-decremental
action potential
GP vs AP: brought about by external stimuli (in sensory
neurons) or by neurotransmitters released in synapses
graded potential
GP vs AP: triggered by membrane depolarization to
threshold
action potential
GP vs AP: potentials can occur in any region of the cell
plasma membrane: in neurons, they occur in specialized regions of synaptic contact with other cells or membrane regions involved in receiving sensory stimuli.
graded potential
GP vs AP: Occur in plasma membrane regions where voltage-gated Na+ and K+ channels are highly concentrated.
action potential
synapses
areas that are well defined specific regions where downstream neurotransmitters are delivered
The Synapse
where the neuron passes its signal to an elector cell
presynaptic terminal
where action potential occurs, carries vesicles of neurotransmitters using microtubules and neurofilaments to the post synaptic element
post synaptic element
receives neurotransmitters (using receptors) from the presynaptic terminal
synaptic cleft
the space between the presynaptic terminal and post synaptic element, enzymes are here to hydrolyze neurotransmitters
steps of the chemical synapse
- AP reaches presynaptic terminal
- depolarization opens ion channels letting Ca2+ in
- Ca2+ triggers release of NT from vessicles
- NT binds to receptors on postsynaptic membrane
- postsynaptic gets a membrane potential
- AP propagates through the next cell
- NT are inactivated
what triggers the release of neurotransmitters in the synapse?
Ca2+
how are neurotransmitters inactivated?
hydrolyzed by enzymes in the synaptic cleft OR transported back into the presynaptic terminals and package into vesicles by proteins
what is the area called where synaptic vesicles will release?
(_________zone)
active zone
post synaptic densities
accumulation of neurotransmitter receptors and other proteins that will support them
what is responsible for docking the vesicles of neurotransmitters to help fuse them to the membrane?
v-snares and t-snares
what induces vesicle fusion with the membrane, but docking of vesicles can occur in its absence?
Ca2+
what happens if v-snares and t-snares get damaged in synapses and they cannot interact?
neurotransmitters will not release
what can cause damage to t-snares and v-snares allowing for neurotransmitters to no longer release?
toxins (botulism, tetanus)
examples of small molecule neurotransmitters
- acetylcholine
- norepinephrine
- epinephrine
examples of neuropeptides
- enkephalin
- oxytocin
(AA and peptides)
how are neuropeptides made?
synthesized in the rough ER and then cleaved from larger peptides
how are small molecule neurotransmitters produced?
enzymatic pathways, processed in the Golgi
do neuropeptides have fast or slow axonal transport?
fast (400 mm/day)
do small molecule neurotransmitters have fast or slow axonal transport?
slow (0.5-5 mm/day)
why are small molecule neurotransmitters transported much slower than neuropeptides?
they do not have to be replaced as often
small molecule: synthesis site
axonal terminal or varicosity (neuromuscular junction)
neuropeptide: synthesis site
nucleus/ER as a propeptide
small molecule: vesicle
small, clear
small molecule: release
low frequency stimulation
small molecule: inactivation
reuptake or enzymes
neuropeptide: vesicle
large, dense
neuropeptide: release
(high or low frequency)
high frequency stimulation
neuropeptide: inactivation
extracellular peptidases
ionotropic receptors
ion channels that open when a ligand attaches
metabptropic receptors
g-protein coupled receptor
ionotropic: receptor
ligand gated channel receptor
ionotropic: structure
4-5 subunits around an ion channel
ionotropic: molecular action
opens ion channel
ionotropic: 2nd messenger?
NO
ionotropic: gating of ion channel
direct
metabptropic: receptor
g-protein coupled receptor
metabptropic: structure
no channel, 7 transmembrane segments
metabptropic: molecular action
activate g-protein
metabptropic: 2nd messenger?
YES
metabptropic: gating of ion channel
indirect
metabptropic: type of synaptic effect
(slow or fast)
slow post synaptic potential
ionotropic: type of synaptic effect
(fast or slow)
FAST excitatory and inhibitory post synaptic potential
acetylcholine receptors
- nicotinic = ionoropic
- muscarinic = metabotropic
norepinephrine receptor
- alpha = metabotropic
- beta = metabotropic
Central Nervous System
brain and spinal cord
Peripheral Nervous Sytem
all neural tissue but the brain and spinal cord, afferent and efferent divisions
afferent division
receives sensory and visceral stimuli and sends information to the CNS
efferent division
the output of CNS, broken into somatic and autonomic
somatic nervous system
voluntary (ex: skeletal muscle)
autonomic nervous system
sympathetic vs parasympathetic vs enteric
sympathetic nervous system
fight or flight
parasympathetic
rest and digest
how many pairs of spinal nerves do humans have?
31
how are the spinal nerves named?
according to the region of the vertebral column to which they are connected
order of the vetebral column
top- cervical, thoracic, lumbar, sacral -bottom
ganglion
a collection or group of neuron cell bodies in the PNS
afferent fibers enter through the ________ root and efferent fibers exit through the _________ root
dorsal, ventral
does sensory information come in through the ventral or dorsal side of the spinal nerves?
dorsal
does motor information come out through the ventral or dorsal side of the spinal nerves?
ventral
neurotransmitter associated with the sympathetic nervous system
norepinephrine (and acetylcholineis used for pre ganglia)
neurotransmitter associated with the parasympathetic nervous system
acetylcholine
define excitable tissue
they can propagate changes in membrane potentials which cause action potentials that cause contraction (muscle)
3 types of muscle
skeletal, cardiac, smooth
striated muscle
skeletal and cardiac
unstriated muscle
smooth
voluntary muscle
skeletal
involuntary muscle
cardiac and smooth
define striated
a repeated pattern along the length of the muscle composed of aligned contractile fibers
what regulates skeletal muscle?
completely depends on signaling from the nervous system to work/contact because it is voluntary
what regulates cardiac and smooth muscle?
the nervous system can influence them but they respond to other stimuli within the body because they are involuntary
myoblasts
muscle cells
what does skeletal muscle look like?
striated, tubular, multinucleated
what does smooth muscle look like?
spindle shaped, non-striated, unicellular
what does cardiac muscle look like?
striated, branched, unicellular
where is cardiac muscle located?
walls of the heart only
myofibril
contractive units packed into a muscle fiber with mitochondria and nuclei
skeletal muscle: muscle fiber
a typical cell packed with myofibrils that push the nucleus to the side
skeletal muscle: endomysium
covering of the muscle fiber
skeletal muscle: fascicle
collections of muscle cells
skeletal muscle: perimysium
covering of fascicles
skeletal muscle: muscle
collection of fascicles
skeletal muscle: epimysium
covering of the entire muscle
skeletal muscle: tendon
attached the muscle to bone
A band (coloring)
dark
I band (coloring)
light
how are skeletal muscles innervated?
by motor neurons, it must come from the ventral side and attach to individual fibers
skeletal muscle: a weak contraction means a ______ motor units are contracting, while a strong contraction means _______ motor units are contracting
few, a lot
how is skeletal muscle formed?
the fusion of myoblasts (why there are multiple nuclei)
what muscle can fatigue?
skeletal muscle
sarcoplasm
muscle cell cytoplasm
sarcoplasmic reticulum
muscle endoplasmic reticulum
sarcolemma
muscle cell membrane
2 types of myofilaments in skeletal muscle
actin and myosin
what is contraction in skeletal muscle?
shortening of myofibrils due to actin filaments sliding over myosin filaments, the length of the filaments remains the same
A band
- thick myosin filament
- dark
- contains the H zone
what protein anchors myosin?
M-line
H zone
ONLY myosin, no overlap of actin
more contraction, ______________ the H zone
smaller
I band
- thin actin filament
- light
what protein anchors actin?
Z-disc
sarcomere
contractile unit (from z-disc to z-disc)
how do t-tubules support contraction?
as an action potential sweeps across the sarcolemma, it will travel down the t-tubules which allows for the action potential to move down into the muscle cell
t-tubules
extensions of the sarcolemma deep into the muscle fibers
sarcoplasmic reticulum
huge organelle that drapes around myofibrils, STORES Ca2+!!
what ion is critical of contraction?
Ca2+
terminal cisternae
relays information to get Ca2+ released
what sites are on the motor head group of myosin?
- actin binding site
- ATP binding site
what orientation does myosin lay?
they lay tail to tail with motor heads on the ends
tropomyosin
prevents myosin from binding to actin in the absence of Ca2+
troponin
calcium binding protein
what happens when calcium binds to troponin?
when Ca is bound, it shifts the position of tropomyosin exposing the myosin binding site so that contraction can occur
why are there so many mitochondria between the myofibrils?
contraction is an ATP dependent process
within the myofibril, each filament is surrounded by _____ light filaments
6
how many nuclei in each cardiac muscle cell?
one or two
why are cardiac cells connected by intercalated disks?
- contains gap junctions
- connected by desmosomes and adherent junctions
why is cardiac muscle auto-rhythmic?
it is involuntary, however the nervous system can have influence
which muscle shows branching?
cardiac
how does cardiac muscle avoid fatigue?
able to completely rest between contractions
how many nuclei are in a smooth muscle cell?
one
dense bodies
what actin is attached to in smooth muscle
caveolae
folds in the cell membrane that contain aggregates of receptors and ion channels
where is smooth muscle found in the body?
walls of hollow organs, vessel walls, erector pili muscles of skin, iris
how does smooth muscle avoid fatigue?
it has slow contractions that can be sustained for long periods of time
what parts of the nervous system can modulate smooth muscle?
autonomic (sympathetic and parasympathetic)
are there gap junctions in smooth muscle?
yes
how does smooth muscle contract?
dense bodies are drawn in together and actin moves over myosin
how are single unit smooth muscles able to contract together in a single unit?
membranes are adhered together at multiple points so excitation is able to sweep through all the muscle through gap junctions
where are single unit smooth muscles found?
organ walls and blood vessels
multi unit smooth muscle
contracts independently from one another and innervated by a single nerve ending
how does multi unit smooth muscle contract separately?
they are separated physically by connective tissue and must be innervated by a single nerve ending
where are multi unit smooth muscle found
iris and erector pili
in blood vessels, contraction __________ diameter, while relaxation ____________ diameter
decreases, increases
how does the cardiovascular system use smooth muscle to control blood flow?
it can contract and relax smooth muscle to restrict or allow blood flow to different capillary beds
what is the purpose of smooth muscle being organized circular and longitudinal?
it is able to constrict the organ in multiple directions
common features of all three muscle types
- generate movement/tension through contraction
- myosin and actin to generate force
- calcium used to trigger contraction
skeletal muscle signal
from somatic motor neuron
cardiac muscle signal
- arises from the heat itself
- some autonomic influence (but not initiate)
smooth muscle signal
multiple sources (internal, local, external)
neuromuscular junction
a synapse that comes into contact with multiple muscle fibers to stimulate them
neuromuscular junction: neurotransmitter
acetylcholine
how does and an action potential at the cells surface reach the myofibrils in the center of the cell to stimulate contractions in skeletal muscle?
t-tubules and their close relationship with the sarcoplasmic reticulum and terminal cisternae
In skeletal muscle: T-tubules and sarcoplasmic reticulum are complexed together throughout the fibers in _____________
triads
dihydropyridine receptor (DHPR)
a voltage dependent calcium channel found between tubules in skeletal muscle, has a relationship with the ryanodine receptor
function of dihydropyridine receptor (DHPR)
triggers intracellular calcium release from the sarcoplasmic reticulum for excitation-contraction coupling of actin and myosin
ryanodine receptor (RYR)
calcium releasing channel in the sarcoplasmic reticulum, has a relationship with the dihydropyridine receptor
function of ryanodine receptor (RYR)
triggering of the DHP receptor causes the ryanodine receptor to open releasing calcium into the cytoplasm from the sarcoplasmic reticulum
What occurs between the RYR and DHPR when depolarization occurs?
DHPR changes conformation allowing RYR to release calcium into the cytoplasm
What occurs between the RYR and DHPR when repolarization occurs?
they return to their original conformation and calcium can no longer exit the RYR
What happens to calcium in order to relax the cell in skeletal muscle?
- RYR is blocked from releasing calcium
- SERCA Pump returns Ca into the SR
SERCA (Sarcoplamic/Endoplasmic Reticulum Ca2+-ATPase) Pump
attached to the membrane of the sarcoplasmic reticulum, uses ATP to move calcium in the cell back into the sarcoplasmic reticulum
What is ATP needed for during a muscle twitch?
- contraction
- relaxation
What is another name for contraction of cardiac muscle?
calcium-induced calcium release
how does contraction of cardiac muscle differ from skeletal muscle?
there is no physical interaction between the sarcoplasmic reticulum and t-tubules in cardiac muscles (no triads)
2 sources Ca2+ uses to flood into cardiac muscle for contraction
- cytoplasm (voltage gated Ca2+ channels)
- sarcoplasmic reticulum (Ca2+ induces Ca2+ to release through the RYR)
How is calcium removed from the cell for relaxation in cardiac muscle?
sodium calcium exchanger (an anti porter transporter protein)
what amount does the sodium calcium exchanger move in and out of the cell?
- 1 Ca out
- 3 Na in
a single cross-bridge cycle uses _____ molecule of ATP and moves the actin filament about _______ nm
- 1 molecule of ATP
- 10 nm
myosin-actin cross bridge cycle
- bind (rebind)
- ratchet (motor head moves actin by changing conformation)
- let go (cycle will continue is Ca is present)
Roles of ATP in the Cross Bridge Cycle
- provide energy for the process
- responsible for detachment
define rigor
the motor head is attached to actin but there is no ATP present (after death) do detachment cannot occur so the myosin cannot release actin
interneuron
a connection point in the CNS that is a connection point between sensory and motor pathways
dorsal root ganglion
a collection of soma in the PNS
is the afferent nervous system dorsal or ventral?
dorsal
is the efferent nervous system dorsal or ventral?
ventral
does the somatic nervous system have ganglion?
NO, all myelinated and fast
does the sympathetic and parasympathetic nervous system have ganglion?
YES, pre ganglion = myelinated and post ganglion = unmyelinated and works slower
which system is faster, the somatic or autonomic nervous system?
somatic
what is the purpose of the autonomic ganglia?
relay information
