1 If three letters together represent a single sound, they constitute a trigraph, such as tch in catch and sch in schmaltz. 2  Similarly, to take the consonant trigraph t c h, the teacher can explain that in this word the three letters together âsayâ the sound. Similarly, to take the consonant trigraph t c h, the teacher can explain that in this word the three letters together âsayâ the sound. 2  Both digraphs and trigraphs in French have their origin in history and phonology.
When a reflex arc consists of only two neurons in an animal (one sensory neuron, and one motor neuron), it is defined as monosynaptic. Monosynaptic refers to the presence of a single chemical synapse.he reaction of teh stretch reflex is trying to keep the muscle at the same length by shortening the muscle. The stretch reflex is important for maintaining muscle tone and adjusting it reflexively. Patellar, (knee jerk).
A withdrawal reflex, also known as a flexor reflex, is a polysynaptic reflex arc. Sensory and motor neurons are part of this reflex, as are association neurons. Pain is the most obvious stimuli that initiates the flexor reflex, as painful stimuli sets the whole reflex into action. reflex arc is in fact the simplest and most primitive nerve pathway in the human body. A reflex arc is designed to administer unconscious automatic actions which are determined to be protective in nature to keep a body in homeostasis.