Psychopharmacology and pharmacodynamics

Full Answer Section

          ological states and behaviors.  

The Neuron's Cellular Structure

  The neuron, or nerve cell, is the fundamental unit of the nervous system, responsible for transmitting electrical and chemical signals throughout the body. While neurons vary in size and shape depending on their function and location, they generally share three main cellular structures:

1. Cell Body (Soma): This is the spherical part of the neuron that contains the nucleus, which houses the cell's genetic material (DNA), and other essential organelles (like mitochondria, ribosomes, endoplasmic reticulum). The cell body is responsible for maintaining the neuron's structure, producing proteins (including neurotransmitters), and carrying out basic cellular functions vital for the neuron's survival. It acts as the metabolic center of the neuron.
2. Dendrites: These are tree-like, fibrous branches that extend out from the cell body. Dendrites act like antennae, specialized to receive incoming electrical and chemical signals from other neurons. They have numerous receptor sites on their surface where neurotransmitters from other neurons can bind, initiating an electrical signal that travels towards the cell body. A single neuron can have multiple dendritic branches, allowing it to receive input from thousands of other neurons.
3. Axon: The axon is a single, long, slender projection that extends away from the cell body, often much longer than the dendrites. Its primary function is to transmit electrical signals (action potentials) away from the cell body to other neurons, muscles, or glands. Many axons are insulated by a fatty substance called the myelin sheath, which is formed by specialized glial cells (oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system). The myelin sheath acts like electrical insulation, significantly increasing the speed at which the electrical signal travels down the axon. At its end, the axon typically branches into multiple axon terminals (also called synaptic terminals or terminal buttons).

 

Synapses and Their Significance

  A synapse is a specialized junction or point of communication where a neuron transmits an electrical or chemical signal to another neuron or to a target effector cell (like a muscle cell or gland cell). It's the critical juncture where information flows from one neuron to the next, forming the basis of neural circuits. There are two main types of synapses:

1. Electrical Synapses: In these less common synapses, neurons are directly connected by gap junctions, allowing ions (and thus electrical signals) to flow directly and rapidly between cells. This facilitates very fast and synchronized activity of groups of neurons.
2. Chemical Synapses: These are the most common type in the human nervous system. At a chemical synapse, there is a tiny gap called the synaptic cleft between the presynaptic neuron (the sending neuron) and the postsynaptic neuron (the receiving neuron).

Sample Answer

        Understanding the intricate relationship between brain function, behavior, and the effects of medication requires knowledge of psychopharmacology, pharmacodynamics, and the fundamental building blocks of the nervous system: neurons and their connections.  

Psychopharmacology

  Psychopharmacology is the scientific study of how drugs affect mood, sensation, thinking, behavior, judgment, evaluation, and memory. It is a specialized field within pharmacology that focuses specifically on psychoactive or psychotropic drugs – those that exert their effects on the brain and nervous system. Psychopharmacology aims to understand the mechanisms by which these drugs alter neuronal communication to produce therapeutic effects (e.g., antidepressants, antipsychotics, anxiolytics) or, in the case of substances of abuse, their non-medical effects.