💢فسيو العصبي 13 ،motor3
#Physiology_of_CNS
#CNS
🔴ي هلا وسهلا فيكم😍❤ وراح نشرح انا وايااااكم اليوم موضوع جديد😍💪 ويلااااا بنااا🏃🏃🏃
*⃣Muscle Reflexes
##generated by the electrical stimulation of muscle afferent nerves (Ia fibers) analogous to the mechanically induced spinal stretch reflex👌👌👌
##وبعد م اتعرفنااااا ع معنى ال muscle reflex راح نتعرف ع انواعه المختلفة👇👇👇
0⃣Stretch (myotatic) reflex—knee jerk :👇👇👇
🔷 is monosynaptic👌
A.Muscle is stretched, and the stretching stimulates group Ia afferent fibers👌
B.Group Ia afferents synapse directly on a-motoneurons in the spinal cord. The pool of
α-motoneurons that is activated innervates the homonymous muscle👌
C.Stimulation of α-motoneurons causes contraction in the muscle that was stretched. As
the muscle contracts, it shortens, decreasing the stretch on the muscle spindle and
returning it to its original length.
D. At the same time, synergistic muscles are activated and antagonistic muscles are
inhibited 👌
🔷Increases in g-motoneuron activity increase the sensitivity of the muscle spindle and
therefore exaggerate the knee-jerk reflex 👌👌👌
1⃣Golgi tendon reflex (inverse myotatic):👇👇👇
🔷 is disynaptic👌
🔷is the opposite, or inverse, of the stretch reflex 👌
A. Active muscle contraction stimulates the Golgi tendon organs and group lb afferent fibers👌
B.The group Ib afferents stimulate inhibitory interneurons in the spinal cord. These interneurons inhibit a-motoneurons and cause relaxation of the muscle that was originally contracted 👌
C.At the same time, antagonistic muscles are excited👌
D.Clasp-knife reflex, an exaggerated form of the Golgi tendon reflex, can occur with
disease of the corticospinal tracts (hypertonicity or spasticity).👌👌
2⃣Flexor withdrawal reflex :👇
🔷is polysynaptic👌
🔷 results in flexion on the ipsilateral side and extension on the contralateral side.👌
*⃣Somatosensory and pain afferent fibers elicit withdrawal of the stimulated body part
from the noxious stimulus.
A. Pain (e.g., touching a hot stove) stimulates the flexor reflex afferents of groups II, III,
and IV.👌
B.The afferent fibers synapse polysynaptically (via interneurons) onto motoneurons in the spinal cord.
C. On the ipsilateral side of the pain stimulus, flexors are stimulated (they contract) and
extensors are inhibited (they relax), and the arm is jerked away from the stove. On the
contralateral side, flexors are inhibited and extensors are stimulated (crossed extension
reflex) to maintain balance.
D.As a result of persistent neural activity in the polysynaptic circuits, an afterdischarge occurs. The afterdischarge prevents the muscle from relaxing for some time .👌👌
## وهيك خلصناااا كل انواع ال Reflex وشرحناااا كل نوووع 👌 واخدناااا امثلة مختلفة لانواع ال Synapse 👌 فهاد المنشور مهم جداااا وركزووو فيه وبالتوفيق للجميع ي ررررب😍🌸
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