(a) What substances are made by endocrine glands?
(b) What is the function of receptors and effectors in our body?

(b) Receptors are an organ or cell that receive stimuli from the surrounding environment (heat, light) and transmit the messages conveyed by them to the spinal cord and the brain as electrical impulses through the sensory nerves and carries to the nervous system.

Effectors are an organ, gland, or a muscle that respond to stimuli especially a nerve impulse according to the instructions sent by the nervous system.