C-Stretch Reflex Flashcards
بسم الله الرحمن الرحيم وبه نستعين
“ وألقي في ألارض رواسي أن تميد بكم وأنهار وسبلا لعلكم تهتدون “
Stimulation Y neurons cause ?
Gamma efferent dischare laeds to ?
3SU
1-Sudden reflex contratcion
2-Stretch sensitivity increased
3-Supraspinal control Of SR
4-Unloading prevention
What is the relation of stimualtion of gamma Y and Muscle contration ?
“لايزال قوم يتأخرون حتي يؤخرهم الله”
Stimulation of y neurons causing the reflex contarction of muscle due to contration of peripheral part of Intrafusal muscle fibers causing stretch of central part the receptor that gives afferent Ia+ II that leaves for the spinal cord synapsing with alpah motor neuron casuing muscle contraction “ExtraFusal”
Illustrate how Y neuron prevents Unloading ?
When muscles is contracted vouluntary , this is done by stimulating Alpha motor neuron and at the same time the Gamma motor neuron is stimulated casuign contraction of peripheral of intrafusal muscle fibers preventing the central part receptor from beeing shortened during muscle volunary contraction making the receptor more senistive to stretch even during muscle contraction .
If y neurons is not stimulated during voluntary contraction this leads to ?
Shorterning of central part of intrafusl muscle fibers becoming not senestive to stretch during muscle contratction casuing unloading of receptor CNS is not informed about the muscle
Mention function of SR
Mentio role of SR in volunatery movments
-Servoassist
-Muscle Tone
-Damping
-Clinical Importance
Servoassist voluntary movments and SR Explain relation .
Explain Y loop ,
Explain Alpha Y coactivation
Explain Force regulation in light of SR
Explain alpha motor neuron recriutment
When you lift a load this casuse stretch of muscle and activation of Alpah motor neuron + y motor neuron whic prevents unload and prevents shorterning of cental part of receptor keeping it seneitive during contraction then when you increased the load lifted more stretch to muscle and receptor sending afferents Ia dynamic to spinal cord casusing more and mroe actication of alpha motor neuron increasing as you increase the load
this is called Y loop or Alpha gamma coactivation or Force Reugation
Mention advantages of Servoassist
1-Assist muscle contraction regulation with minimal brain energy consumed
2-Assist Muscle Weaknes
3-Assist Position during increasing the load called Load Reflex
Muscle tone Define
A Continuous Partial Sub-tetanic static stretch reflex + Alternating Skeletal Muscle contraction
Stimulus of Muscle tone is ? and it casues are ?
Maintained Stretch causes :
1-The length of muscle during rest is less than the distance between its origin to insertion
2-Contiuous gamma static efferents discharge
3-Force of gravity in
-upper limb flexors
-lower limb extensors
-Elevators of Jaw
ايه سبب ان العضلات اللي عندها توووون مش بتدخل في حالة اجهاد ؟
التبادل بين الوحدات الحركية
الانقباض مش بيبفي باقصي قوة لأ ده بيبقي سب تيتانك
نوع العضلات المنقبضة من النوع التأكسدي البطئ :
غرقان امداد شعيرات دموي
غرقان ميتوكوندريا
وشغل ATPase فيه قليل
function of muscle tone ?
بيحافظ علي وضعية الجسم ضد الجاذبية
بيحافظ علي خلفية وضعية زي مثلا عبد الحميد بيقول لورفعت رجل واحدة التوون هيزيد في التانية
بيحافظ علي وضع الاحشاء في مواضعها
بيحافظ علي درجة حرارة الجسم
بيحافظ علي الرجوع الوريدي والليمفاوي
Explain Damping fucntion of SR
Explain Singal Averaging function
Explain way of smoothness of Voulnatry contraction
When you need Voluntary contraction the brain may send irregular impulses that causes more or less contraction in muscle
So the role of Muscle spindle ist to prevents oscillitation of muscle contraction and smoothen the contarction making it more accurate
in Case of strong brain impulses the SR may casue Antaongnist SR To weaken the contraction
In case of Weak brain impulses The SR will increase the force of Contraction in agonist muscle
So defect in muscle spindle casue jerky unsmooth contraction
Mention Clincal imp of SR
اسرع!
Norma SR indicates?
Norma muscle spindle and its afferent and efferents and normal NMJs And normal Muscles And normal Balance between excitatory and inhibitory higher centers controllong SR + Normal Spinal Segments
____________________________
Helps (localization) of Lesion to spinal segments in case of absence of reflex
Helps indicating The muscle tone like in case of hyperReflexia indicates hypertonia
اسرع!
mention faciltatory centers of SR
CaVe MNeP
Caudate Nucleus of Basal Ganglia
Vestibular Nucleus
Motor cortex area 4
NeoCerebellum cereberocerebellum
اسرع!
mention faciltatory centers of SR
CaVe MNeP
Caudate Nucleus of Basal Ganglia
Vestibular Nucleus
Motor cortex area 4
NeoCerebellum cereberocerebellum
Pontine reticular formation Faciltatory intrinsicA
