Question

Explain the organization of the nervous system. Be as detailed as possible and be sure to include in your answer the divisions, structures or organs involved, direction of the transmission of information where appropriate and specific examples for each type of components within the organizational units.

Answer 1

The nervous system consists of two parts, the central nervous system consistsing of brain and spinal cord, the peripheral nervous system consisting of nerves which are outside the CNS.

The CNS includes the brain and spinal cord along with various centers that integrate all the sensory and motor information in the body.The brain is contained within the cranial cavity of the skull, and the spinal cord is contained within the vertebral cavity of the vertebral column. The nervous system is often divided into components called gray matter and white matter, white matter is mainly composed of axons, it includes all of the nerves of the PNS and much of the interior of the brain and spinal cord. Grey matter consists predominately of neuronal cell bodies, Gray matter is found in clusters of neurons in the brain and spinal cord and in cortical layers that line their surfaces. Generaly, a cluster of neuron cell bodies in the gray matter of the brain or spinal cord is called a nucleus, whereas a cluster of neuron cell bodies in the periphery is called a ganglion. The CNS can also be divided into lower centers, which includes the spinal cord and brain stem, that carry out essential body and organ-control functions and higher centers within the brain which are responsible for sophisticated information processing, including our thoughts and perceptions.

The peripheral nervous system itself is divided into two parts, Somatic nervous sytem and autonomic nervous system.

Somatic nervous system, is associated with the voluntary control of the body movements through the use of skeletal muscles. It is responsible for all the functions we are aware of ,like the movement of our arms legs and other parts of our body.The somatic nervous system consists of both afferent (sensory) and efferent (motor) nerves , it is also responsible for the reflex arc, which involves the use of interneurons to perform reflexive actions. Sensory neurons or afferent neurons that carry information from the nerves to the central nervous system, Motor neurons or efferent neurons that carry information from the brain and spinal cord to muscle fibers throughout the body,

Autonomic nervous sytem, The autonomic nervous system is the part of the nervous system that supplies the internal organs, including the blood vessels, stomach, intestine, liver, kidneys, bladder, genitals, lungs, pupils, heart, and sweat, salivary, and digestive glands, it consists of the nerves that originate from or lead to the brain and spinal cor, it also consists of collections of the neuronal cell bodies located outside the central nervous system. These collections of cell bodies are called ganglia. The autonomic nervous system has two main divisions: Sympathetic nervous sytem and parasympathetic nervous sytem.

Sympathetic nervous system, This division of autonomic nervous system is responsible for controlling fight or flight response the sympathetic nervous system is involved in the stimulation of activities that prepare the body for action, such as increasing the heart rate, increasing the release of sugar from the liver into the blood,increasing the respiratory rate,increasing blood flow to muscles, activating sweat secretion, and dilating the pupils. This allows the body to respond quickly in situations that require immediate action

Parasympatehtic nervous system,this division controls the body functions in a calm state, helps maintain normal body functions and conserve physical resources. Once a threat has passed, this system will slow the heart rate, slow breathing, reduce blood flow to muscles, and constrict the pupils. This allows us to return our bodies to a normal resting state.

Generally, both sympathetic and parasympathetic systems target the same organs, but often work antagonistically. For example, the sympathetic system accelerates the heartbeat, while the parasympathetic system slows the heartbeat. Both system play an important role in maintain homeostasis.