Chapter 14 Outline
Organization of Sensory Systems
- Sensory receptor cells can be classified in four different ways
- Sensory receptor cells transduce and encode sensory information
Mechanoreception and Touch
- Insect bristle sensilla exemplify mechanoreceptor responses
- Touch receptors in the skin of mammals have specialized endings
- Proprioceptors monitor internal mechanical stimuli
Vestibular Organs and Hearing
- Insects hear with tympanal organs
- BOX 14.1 Echolocation
- Vertebrate hair cells are used in hearing and vestibular sense
- Vertebrate vestibular organs sense acceleration and gravity
- Sound stimuli create movements in the vertebrate cochlea that excite auditory hair cells
- The localization of sound is determined by analysis of auditory signals in the CNS
Chemoreception and Taste
- Insect taste is localized at chemoreceptive sensilla
- Taste in mammals is mediated by receptor cells in taste buds
- BOX 14.2 Genomics and sweet taste in hummingbirds
Olfaction
- The mammalian olfactory epithelium contains odor-generalist receptor cells
- The vomeronasal organ of mammals detects pheromones
Photoreception
- Photoreceptor cells and eyes of different groups have evolved similarities and differences
- Rhodopsin consists of retinal conjugated to opsin, a G protein–coupled receptor
- Phototransduction in Drosophila leads to a depolarizing receptor potential
- The vertebrate eye focuses light onto retinal rods and cones
- Rods and cones of the retina transduce light into a hyperpolarizing receptor potential
- Enzymatic regeneration of rhodopsin is slow
Visual Sensory Processing
- Retinal neurons respond to contrast
- The vertebrate brain integrates visual information through parallel pathways
- BOX 14.3 What roles do individual neurons play in higher visual integration?
- Color vision is accomplished by populations of photoreceptors that contain different photopigments