Neuroanatomy, Neurophysiology and Neuropharmacology: The Basics
I. Brief, Basic Chemistry Review (Appendix A- pg 486)
A. Elements and Compounds
1. As stated in Chapter 1, the Big Bang initially produced 4 forces- 1. gravity, 2. electromagnitism 3. strong nuclear forces and 4. weak nuclear forces. Chemistry is the study of the weak nuclear forces found in compounds. The weak nuclear forces allow for chemical reactions which are the transfer of ions and molecules to make new molecules and compounds. When wood is burned it turns into ashes and gases and water vapor and also produces heat. These are all chemical reactions. The basis of chemical reactions is the interaction of elemental chemicals. The periodic table lists 92 elements of which only are few are found in living organisms. Some of the most important are listed here.
Q. What are the most important elements in living organisms?
2. Compounds are made from molecules which are made from elements. Elements that are listed on the Periodic Table are comprised of atoms. For instance, when listed on the Periodic Table, Hydrogen has an atomic number of #1 and Oxygen is #16. The atomic number corresponds to the number of protons in the nucleus of an atom of that element. It also corresponds to the number of electrons in the neutral atom. When atoms come together, they make molecular compounds. Water is a compound or molecule. Compounds are created when electrons from different atoms join each other in chemical reactions. For instance, the molecules of water are elements Hydrogen and Oxygen. On each water molecule are two atoms of hydrogen and 1 atom of oxygen (H20). Each atom is composed of subatomic particles, protons, neutrons and electrons, which are positively charged, neutral and negatively charged- in that order. Protons and neutrons are found in the center of the atom, the nucleus and electrons are found in the space around the nucleus. It is very very difficult to separate protons which is a property of strong nuclear forces. The result of breaking those nuclear bonds is an atomic bomb. In a stable state, an atom will have the same number of protons as electrons. Molecules prefer a stable state to an unstable state and this is what drives ma
Q. What is the atomic number for Oxygen, Hydrogen and Carbon? What do these numbers mean?
B. Ions
3. An atom that has gained or lost one or more electron is called an ion. When the compound salt NaCl (Sodium and Chloride) is placed in water it dissolves or dissociates into ions: Na+ and Cl-. Sodium atoms lose electrons and become positively charged (has space available to accept an electron). A negatively charged ion, like Cl- has an extra electron. Thus ions with opposite charges attract each other and ions with the same charge repel each other. This is a property of electromagnitism and contributes to the property of weak nuclear forces.
In some cultures physics and chemistry are taught before biology because these fields underlie the very complex mechanisms necessary for biological systems. The topics above provide an extremely brief background for processes that are involved in synaptic transmission.
