Sepal Sepal A sepal ( or ) is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom. The term "sepalum" was coined by Noël Martin Joseph de Necker in 1790, and derived from the Greek σκεπη ("skepi"), a covering. Collectively the sepals are called the calyx (plural calyces), the outermost whorl of parts that form a flower. The word "calyx" was adopted from the Latin "calyx", not to be confused with "calix", a cup or goblet. "Calyx" derived from
Calyx of Held sensitivity. Both low-threshold K channels and high-threshold delayed rectifier-type K channels are present in presynaptic neurons. There are four low-threshold K channels present: K1.1, K1.2, K1.3, and K7.5. K1.1 and K1.2 are located in the transition zone between the axon and the terminal, while K1.3 K7.5 are located in the calyx. There is a calcium activated potassium channel expressed in the calyx, however this type of channel does not contribute to neurotransmitter release. Within the span of one week, mice subjects (P7 to P14) showed that the density of the K1 and K3 low threshold channels increases, which in turn