Print a copy of “What do you think? Anticipation Guide” Prospectus found in related articles. Read all the instructions. If you accept the instruction, turn around A in the column before learning about your prospectus. If you don`t agree with the instruction, go around in circles in the column before you learn in circle D. While The dazzling work of Ramon y Cajal in solidifying acceptance of the teaching of neurons has been well understood and described , the earlier events that led to the acceptance of cellular theory in the nervous system are not so often recognized . Most of Robert Bentley Todd`s contributions have been overlooked. He suggested that the nervous voïve was the main center of electrical activity in the brain, and he described histology. At that time, Todd (and Bowman) did not have the appropriate techniques to clarify other anatomical details of cell-cell interactions in the ZNS; In addition, the functional concept of synapse was not introduced in Sherrington until 1897. But as Todd`s electrical theory of epilepsy preceded Hughlings-Jackson`s 20-year-old theory of epilepsy. Todd identified the primacy of “nervous vestics” more than 40 years before the wording of Waldeyer`s neuron doctrine in 1891[ 8]. In science, the work of a scientist often leads to a new development or discovery by another scientist. The development of cellular theory would not have been possible without the invention of the microscope and the use of the microscope to understand the structure of living things.
Compare your answers with those in the Before You Learn column. Then check your answers with the answer key in Related Items. The first animal phylum with a nervous system was the Cnidaria, which includes jellyfish, corals, sea amemones and elegantly simple hydra. Unlike sponges, hydra locomote and show active feeding behaviour (Figure 2.1). These behaviors are coordinated and transmitted by a nervous system, a network of specialized units or cells called nerve cells or neurons (box 2.1). Harvey and Danielli (1939) proposed a double lipid membrane, covered with a layer of protein on each side, to take into account measures of surface tension. In 1941, Boyle-Conway showed that the frog`s muscle membrane was permeable to both K and Cla, but apparently not for Na, so the idea of electrical charges in the pores was not necessary, as a single critical size of pores would explain the permeability of K, H and Cla as well as the impermeability to Na , Ca and Mg2. During the same period (Procter-Wilson, 1916) it was shown that gels that do not have a semi-permeable membrane would swell in diluted solutions. Stronger behavioral reactions because several effect cells are influenced Despite their importance, the history of the cell as a reproductive unit of life is still hardly written.