26 JUNE Flashcards
mostly ch. 13 some ch. 12 i think
a crossbridge is
where a myosin attaches to an actin head
what are four things that increase resistance to stretch
- titin
- active contraction
- weak actin myosin bonds
- proprioceptive information
why does titin increase resistance to stretch
tittin is the rubber band around a sacromere
titin runs out of stretch - rubber band just won’t go any more
titin can lead to what pathology
contractures
how does active contraction increase resistance to stretch
the muscle is already stretched so if you stretch an already stretched muscle there is not that much more stretch
because of the amount of sacromeres able to bond and pull apart
active contraction can led to what pathology
involuntary contractures
- parkinsons’ has involuntary contraction of coremessages form damage of brain singals
how do weak actin and myosin bonds increase resistance to stretch
action and myosin are like Velcro attaching to loops
- weak bonds = the Velcro just doesn’t attach
what is a therapeutic approach to weak actin and myosin bonds:
movement
what is a pathology from weak actin and myosin bonds?
immobility
how does proprioceptive information
there is a quick spindle stretch from the muscle spindle that can increase signals to contract
- causes a depolarizing of muscles
what pathology comes from propriceptive info?
depolarizing muscles
what therapeutic approaches come from propriceptive info?
habitually shorten muscles that = a decrease in sacromere
- QUICK STRETCH
muscles repond to what ?
position
stretch
the number of sacromeres responds to
the length of the muscle
correlation between sacromeres / length of muscle
postive:
increase length = increase sacromeres
decrease length = decrease sacromere
why do sacromere remodel according to length?
body wants to produce the best contraction dependent on the muscle position
if you maintain stretch the body
adds sacromeres
if you habitually shorten muscle the body
decreases sacromeres
therapeutic response to habitually shorten muscles
= maintained stretch
= splints
= serial casting
core / proximal muscles are found
medial in the ventral horn
distal muscles are found
lateral in the ventral horn
flexor signals are found
posterior in the ventral horn
extensor signals are found
anterior in the ventral horn
static cocontraction means
that the muscles are opposing in equal opposite directions:
- locks joint in place
dynamic cocontraction means that
the muscles are playing off each other in order to stabilize but also mobilize a joint
alpha-game coactiviation
when alpha MN and gamma MN activate at the same time
so the alpha contracts the muscle
but its keep sensitive w/ gamma
a motor pool is
where all the cells of one muscle gather
correlatation between a spinal level and a muscle
every spinal level contributes to more than 1 muscle
every muscle get input from more than 1 spinal level
there are three neurons which are which?
2 efferent
1 afferent
a motor unit is
one neuorn and all the muscle fibers it innervates
of the three neurons break down what they are
2 efferent = 1. alpha 2. gamma 1 afferent = 3. cell body in dorsal root - pseudounipolar neuron
four characteristics of a slow twitch motor unit:
oxidative metabolism
not alot of tension = longer duration / less force
fatigue resistant
smaller diameter a-alpha
four characteristics of fast twitch motor unit:
glycolysis metabolism
HIGH amounts of tension = strong response
not as fatigue resistant = quick response
larger diameter a alpha
color of fast / slow twitch
slow = red fast = white
gross motor units have
ALOT of muscle fibers per axon
fine motor units have
tiny bit of muscle fibers per axon
ie of gross motor unit
gastroci
2000 muscle fibers per axon
ie of fine motor unit
hand mm
3 muscle fibers per axon
hennemans’ size principle
- states that slow muscle units will be recruited first
- then if you need more power
- recruit fast twitch
UNLESS it is necessary for it to be reversed - like when you fight a bear - conscious movement
why is the hennemans size principle a thing:
because you can depolarize a slow twitch muscle faster
how does the brain recruit motor units?
NOT AT THE SAME TIME
- will CYCLE through motor units
pathology with motor unit
brain doesn’t have enough motor units so can’t cycle though = INCREASE FATIGUE
what does convergence of information mean?
that there are multiple messages form the brain and the sensory receptor that convene on ONE alpha motor neuron
therapeutic response to convergence of information
deep tendon pressure: inhibits messages to relax sensory input says relax
add sensory to interrupt the convening messages to make contraction stop
reciprocal inhibition:
when agonist is facilitated
antagonist is inhibited
how do you mobilize a joint:
facilitate agonist- shorten
inhibit antagonist - lengthen
how do you stabilize a joint
STOP co activation
muscle synergies normal:
working together in voluntary control in any pattern with fx use
muscle synergies abnormal:
muscle working together in limited voluntary control w/ limited patterns
what two ways does reciprocal inhibition start?
- active (from brain)
2. reflex (quick stretch)
stepping pattern generators means
that when we start walking we don’t need further input our bodies just continue to walk
a body schema is
a internal body map
two parts of a reflex:
stimulus
response
where does the hand off between sensory and motor take place?
the spinal cord
list the steps of basic muscle movement:
sensory organ stimulated afferent pathway hand off - connection in spinal cord efferent pathway efferent stimulus to muscle
phasic means
momentary or prolonged stimulus that produces a momentary or prolonged response
phasic starts with what/
the stretch of a muscle spindle Ia fiber
spindle makes direct connection to what?
the alpha motor neuron
steps of phasic contraction:
- muscle spindle stimulated: Ia fiber
- tendon deforms - muscle gets stretched apart = more signals
- hand off in spinal cord
- spindle makes direction connection w/ alpha motor neuron
- contraction of muscle activation of alpha
faciliatated means that
MN was brought closer to an AP
activation means that
an AP was achieved
withdrawal reflex are from
cutaneous receptors which activate
a -delta
a -delta sends out
sharp pain
withdrawal reflex tells you what?
get sharp pain from a -delta
and tell you to get away from stimulus so withdrawals from stimulus
muscles cramps could come from
overworked
- repetitive over contraction
- inability for brain to catch up to cycle motor units properly
