Sensory receptors detect certain types of external or internal stimuli. 272Sensation occurs when sensory receptors send nerve impulses to the brain. 273
14.2 Proprioceptors and Cutaneous Receptors
Proprioceptors in muscles and joints help the body maintain balance and posture. 274Cutaneous receptors in the skin are sensitive to touch, pressure, pain, and temperature (warmth and cold). 274-75
14.3 Chemical Senses
Taste cells within taste buds in the mouth are sensitive to molecules that result in bitter, sour, salty, or sweet tastes. 276Olfactory cells within the olfactory epithelium are sensitive to molecules that result in a sense of smell. 277
14.4 Sense of Vision
The photoreceptors for sight contain visual pigments, which detect light rays. 280A great deal of integration occurs in the retina of the eye before nerve impulses are sent to the brain. 281
14.5 Sense of Hearing
The mechanoreceptors for hearing are hair cells in the cochlea of the inner ear that detect pressure waves. 284
14.6 Sense of Equilibrium
Hair cells in the semicircular canals of the inner ear are responsible for rotational equilibrium. 287Hair cells in the vestibule of the inner ear are responsible for gravitational equilibrium. 287