Final answer:
The effectors in reflexes are muscles and glands, which respond to signals from motor neurons in the central nervous system in somatic reflexes, or via a two-step neuronal pathway in visceral reflexes of the autonomic nervous system.
Step-by-step explanation:
The Reflex Arc Effectors
The effectors in reflexes are the muscles and glands. During a reflex action, motor (or efferent) neurons conduct impulses from the central nervous system to these effector organs. In somatic reflexes, such as the withdrawal reflex, the efferent branch contains the lower motor neuron that projects directly to a skeletal muscle causing it to contract. In comparison, visceral reflexes, which are part of the autonomic nervous system, follow a two-step pathway where the preganglionic fiber synapses on a ganglionic neuron, which then projects to a target effector like cardiac and smooth muscles, or glandular tissue.
The somatic nervous system is responsible for voluntary movements and involves a direct connection from the motor neurons to skeletal muscles. The autonomic nervous system, however, regulates involuntary functions targeting cardiac and smooth muscle, as well as glands, with the visceral reflex arc incorporating an additional synaptic step. Both types of reflex arcs are essential for body function, but the visceral reflexes also include sensations not typically rising to conscious perception, like the pain experienced during a heart attack, which might be referred to other body areas.