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).
1-7. REFLEX ARC An impulse follows a conduction pathway from its origin in the dendrites or neuron cell body in one part of the body to the impulse's end somewhere else in the body.One pathway is called a reflex arc and is a functional unit of the nervous system.The basic parts of a reflex arc are a receptor, a sensory neuron, a center, a motor neuron, and an effector. a. Function of Components of a Reflex Arc.Functions are: (1) Receptor. The receptor activates a nerve impulse in a sensory neuron in response to a change in the body's internal or external environment.(2) Sensory neuron. This neuron conducts the impulse from the receptor to its axonal end in the central nervous system.he receptor activates a nerve impulse in a sensory neuron in response to a change in the body's internal or external environment. (2) Sensory neuron. This neuron conducts the impulse from the receptor to its axonal end in the central nervous system.