receptors and effectors

• receptors are the cells that detect stimuli
• there are many different types of receptors, such as taste receptors on the tongue and sound receptors in the ears
• receptors can form part of a larger, complex organs e.g. the retina of the eye is covered in light receptor cells
• effectors respond to nervous impulses and bring about change
• muscles and glands are known as effectors - they respond in different ways
• muscles contract in response to a nervous impulse, whereas glands secrete hormones