Compare and Contrast Nervous and Hormonal Communication

The nervous system is the entire integrated system of nerve tissue in the body: the brain, brainstem, spinal cord, nerves and ganglia. It is the sensory and control apparatus consisting of a network of nerve cells. The nervous system allows organisms to coordinate bodily reactions from the CNS and gather information from the external environment to be processed in the CNS. The endocrine system is the bodily system that consists of the endocrine glands that release their secretions (hormones) into the bloodstream to reach and act on target cells of specific organs. Both are vital for the survival of multicellular organisms as they allow organism to coordinate complex responses and adapt to constantly changing environments.

The nervous system is made up of the Central Nervous System (CNS), the processing area, and the Peripheral Nervous System which detects and sends electrical impulses that are used in the nervous system. The CNS processes the information received from the peripheral nervous system, it consists of the brain and spinal cord. It is responsible for receiving and interpreting signals from the peripheral nervous system and also sends out signals to it. The nervous system consists of many nerve cells, also known as neurones.

However, the endocrine system secretes hormones directly into the bloodstream; it does not have its own means of transporting messages. The endocrine system is made up of ductless endocrine glands, such as the hypothalamus, pituitary gland, thyroid gland and pancreas, the blood stream and target cells. It is vital for regulating mood, growth and development, tissue function and metabolism. Hormones have structures complementary to the shape of the receptor site on the target cell.

The nervous system delivers signals as electrical impulses along nerve axons. Chemical signals diffuse across synapses to reach other nerve cells so that the impulse can continue. Although the diffusion of the chemical transmitter is slower than electrical impulses, the speed at which information is processed and delivered in the nervous system is very fast. However, the endocrine system uses hormones transported by the circulatory system. This is usually slower than the response of the nervous system due to the delay of circulation. Both systems involve diffusion, across synapses in the nervous system and between blood and tissue in the endocrine system, but the diffusion distances across synapses is much smaller leading to considerably faster transmission.

Another way of contrasting the two systems is specificity. The endocrine system is generally more specific as hormones will only bind to specific receptor sites on their target cells. However, the nervous system supplies groups of tissues or organs. The reactions triggered by nervous impulses do not last for extended periods of time; this is contrasted to the endocrine system, the effects of which can