BIO 1306 Lecture Notes - Lecture 12: Cambrian Explosion, Nerve Net, Cephalization
Document Summary
The human brain contains about ________________ neurons, organized into circuits more complex than the most powerful supercomputers. Powerful imaging techniques allow researchers to monitor multiple areas of the brain while the subject performs various tasks. A recent advance uses expression of combinations of ________________ in brain cells, a technique called brainbow . Concept 49. 1: nervous systems consist of circuits of neurons and supporting cells. By the time of the cambrian explosion more than ________________ years ago, specialized systems of neurons had appeared that enables animals to sense their environments and respond rapidly. The simplest animals with nervous systems, the cnidarians, have neurons arranged in nerve nets. A nerve net is a series of interconnected nerve cells. More complex animals have ________________, in which the axons of multiple neurons are bundled together. Nerves channel and organize information flow through the nervous system. Bilaterally symmetrical animals exhibit cephalization, the clustering of sensory organs at the front end of the body.
