BIOL 1107 Midterm: Exam 5
Document Summary
All animals but sponges have neurons and muscle cells. There are two basic types of nervous systems. The diffuse arrangement of cells called a nerve net. Found in cnidarians (jellyfishes, hydra, anemones) and ctenophores (comb jellies) Includes large numbers of neurons aggregated into clusters called ganglia. Most animals with a cns have a large cerebral ganglia or brain. Sensory cells respond to light, sound, touch, or other stimuli. Sensory cells in the skin, eyes, ears, and nose transmit streams of data about the environment. Sensory cells inside the body monitor conditions that are important in homeostasis, such as blood ph. Dendrites convert chemical signals to electrical signals. Locomotion or movement of an animal on its own power enables the animal to seek food water, maters and shelter, as well as avoid predators. Within each muscle fiber there are many threadlike, contractile structures called myofibrils.
