Chapter 3: Physiological Bases of Behavior

Physiological Bases of Behavior

There are many physiological bases for behaviors. All behaviors are produced and controlled by the brain. Different brain regions are responsible for different behaviors. The brain, in turn, is affected by genetics, nutrition, and myriad environmental factors. 

The study of the physiological bases of behavior is biological or physiological psychology. Most studies in this field relate to the function of neurotransmitters and neurons.

In this chapter, we take a closer look at the communication in the nervous system. The basic hardware of the nervous system is the nervous tissue. Our nervous system is a living tissue composed of cells. There are two types of cells in the nervous system: GLIA and NEURONS or NERVE CELL. First, what is Neuron? It is the individual cells in the nervous system that receive, integrate and transmit information. It is the basic unit of the nervous system. Every neuron has different shapes, sizes and function. There are about approximately trillion of neurons throughout the body which involved in the control of body activities and behavior.

There are four parts of neuron; these are the cell body/Soma, dendrites, axons, and myelin sheath. Cell body contains the nucleus which provides nourishment and insulation. The function of Dendrites is to receive signals from neighboring neurons and carry them back to the cell body, while axons carries messages to the other neuron. Axons terminate in small bulges called TERMINAL BUTTON that send messages to other neurons. Lastly, Myelin sheaths are the fatty tissue and proteins surrounding the axons.

There are three kinds of neuron according to basic function; Sensory (Afferent neurons), Motor (Efferent neurons) and Association/Inter-neurons. Sensory neurons convey information from the body’s sense organs to the brain and spinal cord. This is initiated by receptors-specialized cells in the sense organs, muscles, skin and joints that detect physical or chemical changes and convert these into impulses that pass along the sensory neurons. Motor neurons carry impulses away from the brain and spinal cord to the reacting organs, the muscles and glands. Lastly, the Association Neurons connect the neurons together and combine the activities of the sensory and motor neurons.

In the other hand, Glial cells are the non-neural cells that surround the neurons and ensure that it can perform its function while holding them in place.

There are 3 steps of how the neurons fire; the resting state, the action potential and the Synapse: Sending the message to other cells. Resting state is the state of neuron when not firing a neural impulse. Action potential is the time when there is a release of the neural impulse consisting of a reversal of the electrical charge within the axon. Lastly the Synapse, in this situation, the neurons that send a signal across the gap is called synaptic neuron and the neurons that receive the signals is called the post-synaptic neuron.

Neurotransmitters are also known as the messenger. These are the chemicals that carry messages across the synapse or cell body of a receiving neuron. Neurotransmitter has five functions: these are the acetylcholine, Norepinephrine, dopamine, Gamma amino. Acetylcholine is located at brain, spinal cord, ANS, selected organs and release at neuromuscular junctions. Norepinephrine is also located at brain, spinal cord and it’s regulates physical logical arousal, learning, memory and emotion. Dopamine is only located at brain and it’s linked to muscle activity, emotional arousal, learning memory. Gamma Amino is also located at brain, spinal cord and it’s involved in motor behavior and arousal.

The Peripheral nervous system can be divided into somatic nervous system and autonomic nervous system. Somatic nervous system is made up of nerves that connect to voluntary skeletal muscles and to sensory receptors. These nerves are the cables that carry information from receptors in the skin, muscles and joints to the central nervous system to the muscles. The Autonomic nervous system is concerned with the parts of the body that keeps us alive- the heart, blood vessels glands, and other organs that operate involuntarily without our awareness.

The Central nervous system has two parts: the brain and the spinal cord. The brain is the true core of the nervous system. It takes information from senses processes it, makes decision and sends commands to the rest of the body. The major parts of the brain is the Hindbrain (consist of medulla, pons, cerebellum), Midbrain (located between hindbrain and forebrain) and the Forebrain (largest part of the brain).

The Cerebral cortex consists of a mass of deeply folded, rippled, convoluted tissue. It has four major sections called Lobes. The Frontal lobe (lies at the front center of the cortex), the Parietal Lobe (located at the top of the head function), Temporal Lobe (found in lower center portion of the cortex), and the Occipital lobe (found at the back of the head). The Limbic System or the old brains are found in the inner margin of the upper brain which includes Thalamus (Inner chamber) and hypothalamus (below the inner chamber).

For Conclusion, Our Brain is the most important parts of the body because it controls other organs and our mind. Brain is like a command center that commands to other organs to move or make their own job.