Question

Explain why a message moving along nerve pathways takes time.

Answer 1

The conduction of nerve impulses relies upon the movement of positively-charged ions across the nerve cell membrane. The entry of sodium into the cell produces a wave of positive charge that travels down the length of an axon. Then chemicals called neurotransmitters are secreted out of the end of the axon onto the next nerve in the series (the postsynpatic nerve). This narrow space in between neurons is called the synapse. These neurotransmiiters released by the presynaptic nerve bind to receptors on the postsynaptic nerve. The binding of these receptors opens up channels in this second nerve's membrane that allow sodium ions to enter the nerve cell and initiate another wave of positive charge, and so on... The nerve signal can only move as fast as these ions and neurotransmitters can diffuse to generate this process. 

As a professional athlete repeats a given activity many times over, the nerve cells "upregulate" their receptors, meaning that they produce additional receptors to put in the membrane. This is just a natural reaction to the nerve being repeatedly stimulated in the same way over and over. When neurotransmitter is secreted from the presynaptic neuron, there are more receptors on the postsynaptic neuron for it to bind, more channels open up, more ions enter in a shorter time and build up positive charge to create the impulse faster, and so the overall effect is faster. 

Additionally, there are sheaths of fatty tissue (called myelin) that insulate the charge in the neuron and allow it to be conducted faster. As people age, these sheaths can start to degrade, making the nerve cell more "leaky" and causing the impulse to be conducted more slowly. 

Answer 2

Another function of the nervous system is to control the body. This is done by taking information from the environment using sensory receptors, sending signals that encode this information into the central nervous system, processing information to determine the appropriate response, and sending output signals to muscles or glands to activate responses. The evolution of a complex nervous system has enabled various animal species to have more advanced perceptual abilities such as vision, complex social interactions, fast coordination of organ systems, and integrated signal processing.

Further explanation

The nervous system is the body's network that coordinates the important behaviors and functions of our body, including breathing, digestion, blood circulation, excretion, sweating, movement, perception, speech, sleep, learning, and memory. The brain codes our personal identity, as tragically proven by cases of personality loss in brain disorders such as Alzheimer's disease or some cases of stroke.

The nervous system is the most complex and most important network because it consists of millions of nerve cells (neurons) that are interconnected and vital for the development of language, mind, and memory. The main work units in the nervous system are neurons that are bound by glia cells.

The nervous system is vulnerable to damage in various ways, as a result of genetic defects, physical damage due to trauma or poison, infection, or aging. The specifics of medical research in the field of neurology study the causes of damage to the nervous system, and look for interventions that can prevent or repair them.

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The nervous system : brainly.com/question/2212243

Details

Class : middle school

Subject : biology

Keywords : The nervous system, functions, body, cells, system control

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