推 killer200304:推一個@@ 11/20 21:59
推 maginot:謝謝囉^^ 11/20 23:52
推 xiaoa:推推~ 11/21 12:59
大家好我是鄭家成(就是和謝郁、貓同一組的那個轉系生)，就是很多同學都沒有查到
雙手反扣的資料，所以在此將我查到的網站PO給跟我一樣報告被R的大家QQ
Jendrassik maneuver
Many of the homonymous alpha-motoneurons are not discharged by the Ia
afferent fiber input, but have EPSPs evoked in them that do not achieve the
critical firing level. The excitability of the motoneuron is therefore
increased. This group of excited neurons is called the subliminal fringe. The
presence of the subliminal fringe accounts for enhancement of the reflex
response under certain circumstances, for example with the Jendrassik
maneuver. In the Jendrassik maneuver, the fingers of the two hands are locked
together and one hand pulls against the other while the tendon tap reflex is
evoked. The reflex evoked is stronger than in the absence of the maneuver.
(Interestingly, mental arithmetic and a number of other activities will do
the same thing!) During the Jendrassik maneuver activity, originating perhaps
in the cervical enlargement of the spinal cord or some other rostral center,
descends the spinal cord to excite alpha-motoneurons. This activity by itself
does not cause the alpha-motoneurons to discharge or the muscle to contract,
but when added to the subthreshold excitation of the subliminal fringe caused
by the tap-induced muscle stretch, it causes the neurons in the subliminal
fringe to discharge. The reflex contraction will therefore be larger than
normal. There may also be some influence of increased gamma-motoneuron
activity, increasing the sensitivity of the primary spindle endings, but this
influence should be small because the stimulus for the reflex is very brief.
http://www.unmc.edu/physiology/Mann/mann15.html
http://en.wikipedia.org/wiki/Jendrassik_maneuver
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 125.225.168.152