BIOL 1107 Lecture Notes - Lecture 55: Endoplasmic Reticulum, Globular Protein, Phosphate
Document Summary
Sessile animals rely on internal movements, such as those of the heart muscle or gills, to accomplish internal processes. In order to produce movement, muscles must pull against resistance such as that provided by a skeleton. o. Skeletons provide attachment sites for muscles and a support system for the body"s soft tissues. Three types of skeletons are found in animals: Exoskeletons are hard, hollow structures that envelop the body. Hydrostatic skeletons use the pressure of internal body fluids to support the body. In all vertebrate animals, the movements of paired muscles are coordinated by motor neurons that originate in the brain or spinal cord. These motor neurons project from processing centers that receive input from sensory systems: motor neuron activity changes in response to information about balance, smells, sights, and sounds. Thus, an animal"s movements are directly tied to its sensory systems. The interplay of sensory input and motor output results in coordinated movements.
