Sensory Systems Innovative Learning Solutions （感官系统创新的学习方案）.pdfVIP

55 Sensory Systems Concept Outline 55.1 Animals employ a wide variety of sensory receptors. Categories of Sensory Receptors and Their Actions. Sensory receptors can be classified according to the type of stimuli to which they can respond. 55.2 Mechanical and chemical receptors sense the body’s condition. Detecting Temperature and Pressure. Receptors within the skin respond to touch, pressure, pain, heat and cold. Sensing Muscle Contraction and Blood Pressure. A muscle spindle responds to stretching of the muscle; receptors in arteries monitor changes in blood pressure. Sensing Taste, Smell, and Body Position. Receptors that respond to chemicals produce sensations of taste and smell. Hair cells send nerve impulses when they are bent. 55.3 Auditory receptors detect pressure waves FIGURE 55.1 in the air. Photoreceptors in the vertebrate eye. Rods, the broad, tubular The Ears and Hearing. Sound causes vibrations in the cells, allow black-and-white vision, while cones, the short, tapered ear that bend hair cell processes, initiating a nerve impulse. cells, are responsible for color vision. Not all vertebrates have Sonar. Bats orient themselves in space by emitting sounds both types of receptors. and detecting the time required for the sounds to bounce off objects and return to their ears. ll input from sensory neurons to the central nervous 55.4 Optic receptors detect light over a broad range of Asystem arrives in the same form, as action potentials wavelengths.