Test Three Flashcards
purpose of postsynaptic neuron
carries out action, direct link to effector
receptors are capable of sensing what
touch, pain, temp and chemical stimuli
what causes the depolarization of postsynaptic membrane
neurotransmitter
where is the vestibular apparatus located
in the inner ear
what is negative contraction
tension going opposite direction of where muscle is going
efferent division is made up of
somatic and autonomic motor
when is max velocity greatest
at lowest force
what is irritability is neurons
ability to respond to stimulus and convert it to a neural impulse, respond to action
slow twitch and action potential
slow for myosin to attach to actin, slow from when signal arrive to force is longer
function of endomysium
surrounds individual muscle fibers
what are cross bridges
myosin attaching to actin
what is extensor
increase joint angles
what are free nerve endings
sensitive to touch and pressure, initially strongly stimulated then becomes adapted
after stimulation in parasympathetic division what happens to ACh
degraded by acetylcholinesterase
function of external lamina
just below endomysium
force generation in muscle depends on
types and number of motor units recruited, initial muscle length, and nature of the neural stimulation of motor units
how does the potential membrane resets
with the sodium potassium pump
what maintains resting membrane potential
sodium potassium pump
anatomy of transverse tubules
extend from sarcolemma to sarcoplasmic reticulum
if we arent using muscle what is happening with signal
muscle not producing signal for protein synthesis and reduces stimuli
what are the fiber types of endurance athletes
high % of slow fibers
what is the motor end plate
pocket formed around motor neuron by sarcolemma
what does IPSP cause
hyperpolarization
the somatic nervous system controls what
skeletal muscle
what is conductivity in neurons
transmission of the impulse along the axon
what is another way to control of the internal environment besides nervous system
endocrine system
what must happen first for the cascade of events for muscle contraction to occur
nerve signal
what are the chemical that muscle chemoreceptors are sensitive to
H+, CO2, K+
what is oxidative capacity
number of capillaries, mitochondria, and amount of myoglobin/ ability to perform aerobic energy production
what does an excitatory postsynaptic potential (EPSP) do
causes depolarization
why is there is negative charge in the cell and not equilibrium
due to leaky K+ channels
what is muscle fatigue
decrease in muscle force production, reduce ability to perform work
what are the two muscle action
flexors and extensors
somatic motor neurons of PNS function
responsible for carrying neural messages from spinal cord to skeletal muscles
when does the action potential occur
when a stimulus of sufficient strength depolarizes the cell
what is the sensory division of the PNS
afferent fibers transmit impulses from receptors to CNS
where is the tension applied to in muscle
tendon
what is the voltage is the neurons
-40 to -75 mv
what helps recruit fast motor units faster
training
what is temporal summation
summing several EPSPs from one presynaptic neuron, increase rate=increasee strength
EPSP increases what
neuronal permeability to sodium
why does withdrawal reflex occur
response to sensory input
what do fast fibers have a greater speed of shortening
SR releases Ca++ at a faster rate and has higher ATPase activity
what fiber type has the maximal force per cross sectional area
fast fibers 2a and 2x, have more cross bridges
what is the smallest contractile unit
sarcomere
where does a neurotransmitter bind to
receptor on postsynaptic membrane
what is isometric
muscle exerts force without changing length, pulling against immovable object
how much in total body weight is the skeletal muscle
40 to 50%
what happens when myelin sheath deteriorates
progress loss of nervous system function, fatigue, muscle weakness, poor motor control, loss of balance, mental depression
what is lamina
put a sleeve or covering on something like a sarcolemma
is fiber type the only variable to determine success in athletic event
no
what does central fatigue do
depletion of excitatory neurotransmitters in the motor cortex and reduces motor output to muscle
what is a motor unit
motor neuron and all the muscle fibers it innervates
if you have more damage to muscle then what happens to fore
decreases
how does strength training induce change in muscle
increase in muscle fiber size (hypertrophy), increase in muscle fiber number (hyperplasia)
what is repolarization
return to resting membrane potential
what are the two main characteristics of muscle fiber types
biochemical property and contractile property
what type of neural stimulation of motor units is needed for force regulation
frequency of stimulation (simple twitch, summation, tetanus)
what is spatial summation
summing from several different presynaptic neurons, different neurons acting on same tissue
where are pacinian corpuscles found
tissues around joints
what determines the resting membrane potential
permeability of plasma membrane to ions, difference in ion concentrations across membrane
function of sarcoplasmic reticulum
storage cites for CA++ and terminal cisternae
what is the neuromuscular junction
the junction between motor neuron and muscle fiber
where are golgi type receptors found
ligaments and around joint
the autonomic nervous system controls what
smooth muscle, cardiac muscle, glands
what is the pathway of the neural reflex with withdrawal reflex
sensory nerve sends impulse to spinal column, interneurons activate motor neurons, motor neurons control movement of muscles
cerebellum does what type of movement
fast
the autonomic motor system is made up of
sympathetic, parasympathetic and enteric
how does training help with recruiting type 2
helps selectively recruit type 2 and jump over type one
what type of motor units produce greater force
more motor units and fast motor units
how is it possible to gain strength with GTO
ability to voluntarily oppose GTO inhibition
withdrawal reflex is
the reflex contraction of skeletal muscle
what covers the axon
schwann cells, myelin sheath along length of axon
what are the fiber types in nonathletes
50% slow and 50% fast
where is the threshold located on the neuron
axon hillock
is a neuron faster or muscle twitch
neuron
what is multiple sclerosis
neurological disease that destroys myelin sheaths of axons
cell body structure
contains the nucleus
purpose of presynaptic neurons
can excite or inhibit post
what is a motor unit
motor neuron and all fibers it innervates
how can you improve multiple sclerosis
exercise
what is vestibular apparatus sensitive to
changes in linear and angular acceleration ( stimulated by head movement)
what are isotonic exercise
concentric and eccentric
what is ideal length for force regulation
where we can form the most cross bridges
what % higher does type 2 fibers have in max force per cross sectional area
10 to 20%
force production is related
to number of myosin cross bridges in strong binding state
function of epimysium
surrounds entire muscle
before action potential could travel down T tubule what must happen
Ach binding
what is the most ion in the extracellular fluid concentrations
Na+ and Cl-
what is the motor division of the PNS
efferent fibers transmit impulses from CNS to effector organs
what happens with fatigue and high intensity exercise
accumulation of lactate, H+, ADP, Pi, and free radicals
which fiber type has higher max velocity
type 2
function of sympathetic division
release norepinephrine to excite effector organ
function of motor cortex through thalamus
forwards message sent down spinal neurons for spinal tuning and onto muscle
functions of the skeletal muscle
force production for locomotion and breathing, force production for postural support, and heat production during cold stress
function of gamma motor neurons
stimulate intrafusal fibers to contract with extrafusal fibers
what is the sliding filament model
muscle shortening occurs due to movement of the actin filament over the myosin filament, reduces the distance between z lines of sarcomere
if you have a small muscle change then that leads to what type of ROM
long range of motion
what is the nervous system made of
central and peripheral
major structures of brain stem
medulla, pons, midbrain, reticular formation
what is sarcopenia
decrease levels of testosterone and decreasing activity that males experience
purpose of myelin
speed up conduction of signal and direct signal
function of synapse
contact points between axon of one neuron and dendrite of another neuron
motor cortex function
motor control and voluntary movement
what does an action potential do in a neuron
open Na+ channels and Na+ diffuses into cell causing it to become more positive
how does atrophy occur
due to prolonged bed rest, limb immobilization, reduced loading during space lift
are effect organs under voluntary or involuntary control
involuntary
what is the size priniciple
smallest motor units recruited first
whats the length of a contractile unit
z disc to z disc
what is force velocity relationship
if velocity increases then force decreases and vice versa
function of dendrites
conduct impulses toward cell body
function of cerebellum
coordinates and monitors complex movement which incorporates feedback from proprioceptors
speed of contraction is based on what for muscle fiber types
myosin ATPase activity
what are the two type of muscle action
isometric and isotonic
cerebellum initiates what
fast, ballistic movements
what is atrophy
loss of muscle mass and strength
what are contributing factors for muscle fatigue
high intensity exercise
and long duration exercise
what is a muscle twitch
contraction as the result of a single stimulus
what else does the vestibular apparatus do during exercise
head and eye movement
characteristics of type 1 fibers
slow twitch, slow oxidative, lowest power, highest capacity, most mitochondria, high capillaries
what is the neuromuscular cleft
short gap between neuron and muscle fiber
what are proprioceptors
receptors that provide CNS with info about body position
joint proprioceptors have what type of receptors
free nerve endings, golgi type receptors, pacinian corpuscles
what is important about type of myosin ATPase
speed of ATP degradation, faster detachment and reattachment to and from actin
what is a neurotransmitter
chemical messenger released from presynaptic membrane
what is maximal force production
force per unit of cross sectional area
what is the all or none law
once a nerve impulse is initiated, it will travel the length of the neuron but has to reach threshold
what fibers do we gain during muscle loss from age
slow fibers
what is the central governor theory
central control center regulates exercise performance and reduces motor output to exercising muscle
what are the fiber types in power athletes
high % in fast fibers
what initial muscle length is good for force generation
ideal length and increased cross bridge formation
what happens when Ach is released from motor neuron
causes and end-plate potential
after stimulation with sympathetic division, what happens to NE
removed from synapse or inactivated
what is repolarization in neurons
K+ leaves cell rapidly, Na+ channel close
whats the difference between endocrine and nervous system
fast response control system for nervous and hormonal is long enduring fine tuning system (slow)
what causes damage in muscle
myosin heads are being pulled and stretched but not detaching
how does endurance training induce change in muscle
increase in oxidative capacity
muscle spindle consists of
intrafusal fibers and gamma motor neurons
what allows for fine tuning of motor program
feedback from muscle receptors and proprioceptors
muscle chemoreceptors are sensitive to
changes in the chemical environment surrounding the muscle
what does central fatigue affect
higher brain centers and motor neurons
structure of gray matter
no myelin to allow nerve signal to go everywhere
control of motor function happens with
subcortical and cortical motivation areas, cerebellum and basal ganglia, motor cortex through thalamus
what can help improve strength and endurance for age related change in skeletal muscle
regular exercise
what does the cerebellum and basal ganglia do with control of motor function
covert rough draft into movement plan
afferent division is made up of
somatic (musculature), visceral (organs) and special sensory (chemo and baroreceptors)
brain stem responsible for
metabolic functions, cardiorespiratory control, complex reflexes
how long is initial atrophy and why
2 days bc decreased protein synthesis
muscle spindle responds to
changes in muscle length (stretch of muscle) and wants to contract muscle
how does GTO work
stimulation results in reflex relaxation of muscle and inhibitory neurons send IPSPs to muscle fibers
whats included in a sarcomere
Z line, M line, H zone, A band, and I band
what is kinesthesia
conscious recognition of the position of body parts and limb movement rates
what is the recruitment pattern during incremental exercise
type s, type FR (2a), type FF (2x)
what is a depolarization
electrical signal that causes a chemical release that causes a mechanical event
intrafusal fibers run what to normal muscle fibers
parallel
what is the cross extensor reflex
opposite limb supports body during withdrawal of injured limb, activates antagonist on opposite limb
why are the smaller motor units recruited first
produce larger EPSP and result in action potential sooner bc they have smaller thresholds
what is innervation ratio
number of muscle fibers one neuron innervates
what is the innervation ratio
number of muscle fibers per motor unit, low number of fibers= fine motor control, high number of fibers= less fine motor control
what is a power stroke
formation of cross-bridges between actin and myosin filaments
if there is more muscle how much force
more force can be generated
during hyperpolarization, what is the voltage in the cell
-110 mv
goal of summation is
help make sure event actually occurs
what happens during excitation contraction coupling
action potential travels down t tubules and causes release of Ca++ from SR, Ca++ binds to troponin and causes position change of tropomyosin exposing active site of actin, strong binding state formed between actin and myosin and contraction occurs.
what gate is closed during IPSP
close sodium gates
how much muscle mass is lost between 25 and 50
10%
central governor theory protects against
catastrophic disruptions to homeostasis
in a velocity of movement, the power generated is greater in a muscle with a higher percent in
fast twitch fibers
basal ganglia does what type of movement
slow, deliberate
what is another name for myosin
thick filament
what does the subcortical and cortical motivation areas do
send a rough draft of the movement
if you want more precision with muscle
less muscle fibers per one neuron
at older age what fiber type are we losing
type 2
what are the contractile properties of muscle fiber types
maximal force production, speed of contraction and muscle fiber efficiency
what is the ratio of force and time
force increase when time decreases
how many heads are on one myosin
6
what is required for muscle contraction, energy wise
myosin ATPase breaks down ATP as fiber contracts
how does further atrophy occur
reduced protein synthesis
what is spinal tuning
voluntary movement translated into appropriate muscle action
what is the function of the general nervous system
control of the internal environment, voluntary control of movement, programming spinal cord reflexes, assimilation of experiences necessary for memory and learning
where is Ach released from
motor neuron
what concentric
muscle shortens during force production
is the withdrawal reflex of the skeletal muscle dependent on higher brain centers
no so the rate of response can be fast
what are the biochemical properties of muscle fiber types
oxidative capacity and type of myosin ATPase
what is the stretch reflex
stretch on muscle causes reflex contraction
how much muscle mass is lost between age 50-85
40%
what is an end plate potential
depolarization of muscle fiber
cerebrum has what two cortexes
cerebral and motor
how does EPSP and IPSP play a role in withdrawal reflex
EPSP to muscle to withdraw from stimulus (activate) and IPSP to antagonist muscle (inhibit)
what is inhibitory postsynaptic potentials
move the difference of the 2 areas of membrane mover farther apart, making it more difficult to reach threshold, making harder for action to take place
what are contractile protein
actin and myosin
how many actin does one myosin act on
6
what is motor unit recruitment
recruitment of more muscle fibers through motor unit activation
purpose of parasympathetic division
release ACh that inhibits efector organ
when do you start to decline with skeletal muscle
40 y.o.
what are the muscle proprioceptors
muscle spindle and golgi tendon organ
what is involuntary drive
what you can contract beyond what you think you can do
what do myofibrils contain
contractile proteins
temporal and spatial summation occurs with what
EPSP
what makes up the PNS
neurons outside the CNS, sensory and motor division
what is the most ion in the intracellular fluid concentrations
K+
why is atrophy not permanent
can be reversed with resistance training
what is excitation contraction coupling
depolarization of motor end plate is coupled to muscular contraction
cerebellum has connection to
motor cortex, brain stem, and spinal cord
what does motor end plate look like
depression allowing more surface area to allow more receptors in the pocket
fast twitch fiber and action potential
arrival of electrical signal and then increase of force is much shorter
characteristics of type 2x fibers
fast twitch, fast glycolytic, highest power but lowest capacity
function of autonomic nervous system
responsible for maintaining internal environment
function of perimysium
surrounds bundles of muscle fibers (fascicles)
what is eccentric
muscle produces force but length decresase
cerebral cortex function
organization of complex movement, storage of learned experiences, reception of sensory info
what happens to H zone during contraction
disappears
where are proprioceptors located
joints and muscles
location of sarcolemma
muscle cell membrane
speed of shortening is greatest in what fiber
fast fibers
what is the resting membrane potential
negative charge inside cells at rest
function of vestibular apparatus
responsible for maintaining general equilibrium and balance (head position)
how many skeletal muscles are in the human body
400
function of golgi tendon organ
inhibit recruitment of motor units and causes relaxation
function of muscle proprioceptors
provide sensory feedback to nervous system from tension development by muscle and account of muscle length
what is the most powerful contraction you can do
isometric
function of axon
carriers electrical impulse away from cell body
what are the requirements for electrical activity in neurons
irritability and conductivity
what makes up the CNS
brain and spinal cord
a neuron fires when
a stimulus changes the permeability of the membrane allowing sodium to enter at a high rate
function of golgi tendon organ
monitors tension developed in muscle and prevents muscle damage during excessive force generation
is atrophy permanent
no
what happens with fatigue and long duration exercise
muscle factors due to accumulation of free radicals, electrolyte imbalance and glycogen depletion, central fatigue from reduced motor drive to muscle from CNS
what are the structures of a neuron
cell body, dendrites, axon and synapse
what is flexor
decrease joint angle
characteristics of type 2a fibers
intermediate fibers, fast oxidative glycolytic fibers
what is another name for actin
thin filament
what are the motor functions of the spinal cord
withdrawal reflex, other reflexes involved with voluntary movement, spinal tuning
what ions are involved with the resting membrane potential
Na+, K+, Cl-, and Ca++
muscle chemoreceptors send info to and why
CNS about metabolic rate of muscular activity which can help regulate cardiovascular and pulmonary responses
function of pacinian corpuscles
detect rate of joint rotation
what determines the amount of force produced
number of cross bridges
what are the sources of ATP for energy for muscle contraction
phosphocreatine, glycolysis, oxidative phosphorylation
what determines how much O2 uptake is utilized in muscle fiber types
number of mitochondria
what is the voltage in the muscle
-95 to -100 mv
