How does the nervous system function in response to internal and external stimuli?

The nervous system responds to internal and external stimuli through sensory receptors and nerve impulses.

The nervous system is responsible for detecting and responding to changes in the internal and external environment. Sensory receptors located throughout the body detect stimuli such as light, sound, touch, and temperature, and convert them into nerve impulses that are transmitted to the brain and spinal cord. The brain and spinal cord then process this information and generate appropriate responses.

The nervous system also responds to internal stimuli, such as changes in blood pressure or hormone levels. For example, if blood pressure drops, sensory receptors in the blood vessels detect the change and send nerve impulses to the brain. The brain then sends signals to the heart and blood vessels to increase blood pressure and maintain adequate blood flow to the body's organs.

The nervous system's response to stimuli is coordinated by two main divisions: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord, while the PNS includes all the nerves that extend from the CNS to the rest of the body. The PNS is further divided into the somatic nervous system, which controls voluntary movements, and the autonomic nervous system, which controls involuntary functions such as heart rate and digestion.

In summary, the nervous system responds to internal and external stimuli through sensory receptors and nerve impulses. This response is coordinated by the CNS and PNS, which work together to maintain homeostasis and ensure the body's survival.