Described what makes up the Central Nervous System and the P…

Described what makes up the Central Nervous System and the Peripheral Nervous System.  Describe what role the two divisions of the Autonomic Nervous System play in behavior. (Response should be no less than 150 words in length and information from our textbook should be used to support the responses.  Citations must be included in the body of the post and a reference section should be included at the end of the post.)

The Central Nervous System (CNS) and the Peripheral Nervous System (PNS) are two fundamental divisions of the human nervous system. The CNS mainly consists of the brain and the spinal cord. It is responsible for receiving and processing sensory information and sending out motor commands. The brain, being the major component of the CNS, integrates different sensory inputs, controls voluntary movements, and coordinates various cognitive functions such as thinking and memory. On the other hand, the spinal cord acts as a conduit between the brain and the PNS, relaying signals to and from the peripheral nerves.

The PNS, situated outside the CNS, extends throughout the rest of the body. It consists of twelve pairs of cranial nerves that emerge directly from the brain, and thirty-one pairs of spinal nerves that emerge from the spinal cord. The PNS includes both somatic and autonomic nervous systems. The somatic nervous system controls voluntary movements of skeletal muscles. For example, when you decide to raise your hand, signals from the motor cortex of the brain travel through the spinal cord and reach the muscles responsible for the action, causing your hand to move.

The autonomic nervous system (ANS) plays a vital role in regulating various bodily functions involuntarily. It is further subdivided into two branches: the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is responsible for the body’s “fight or flight” response, which prepares the body to deal with stressful situations. It activates physiological changes such as increased heart rate, dilation of blood vessels, and secretion of stress hormones like epinephrine and norepinephrine. Activation of the sympathetic nervous system leads to heightened alertness and quick physical reactions that help individuals respond to potential threats.

On the other hand, the parasympathetic nervous system functions as the counterpart to the sympathetic system, actively promoting relaxation and restoration. It helps the body “rest and digest” by conserving and restoring energy. When activated, the parasympathetic nervous system decreases heart rate, constricts blood vessels, and promotes digestion. This division helps to restore equilibrium after a stressful event and conserves energy during periods of relaxation.

In terms of behavior, both the sympathetic and parasympathetic divisions of the ANS play significant roles. The sympathetic division, through its activation, prepares individuals to either confront or flee from perceived threats. This physiological response supports behavior by increasing alertness, enhancing physical performance, and mobilizing energy resources. For instance, when faced with a dangerous situation like encountering a predator, the sympathetic nervous system rapidly increases heart rate and dilates blood vessels, enabling an individual to either engage in combat or escape from the danger.

Moreover, the parasympathetic division of the ANS exerts an opposing influence on behavior. By promoting relaxation and conservation of energy, it facilitates activities such as rest, digestion, and recovery from stress. For example, after a stressful event, activation of the parasympathetic nervous system helps the body return to a state of calmness and promotes recovery by slowing down heart rate and facilitating digestion.

In summary, the CNS and PNS are two major divisions of the nervous system. The CNS consists of the brain and spinal cord, responsible for processing and integrating sensory information. The PNS contains cranial and spinal nerves, facilitating communication between the CNS and the rest of the body. The autonomic nervous system, a subdivision of the PNS, comprises the sympathetic and parasympathetic branches. These branches of the ANS have distinct effects on behavior, with the sympathetic division preparing individuals for action and the parasympathetic division promoting relaxation and restoration. These systems work in harmony to regulate various bodily functions and adapt to external stimuli.