Understanding the Human Nervous System and Brain Functions

The Nervous System

The nervous system allows us to respond to changes in our environment and coordinate our actions. It consists of two key parts:

• Central Nervous System (CNS)
• Peripheral Nervous System (PNS)

The Peripheral Nervous System

The peripheral nervous system is divided into two components:

• Autonomic Nervous System: Controls unconscious activities. It is further split into the sympathetic nervous system (prepares the body for action) and the parasympathetic nervous system (calms the body down).
• Somatic Nervous System: Controls conscious activities and connects the CNS with the senses.

Neurons and Neurotransmission

Cells of the nervous system are called neurons (nerve cells). They transmit information as electrical impulses throughout the body. There are three primary types:

• Sensory neurons: Transmit electrical impulses from receptors to the CNS.
• Relay neurons: Transmit electrical impulses between sensory and motor neurons.
• Motor neurons: Transmit electrical impulses from the CNS to effectors.

Neurotransmitters (chemical messengers) are chemicals that enable neurotransmission by carrying signals between neurons. These can be influenced by diet, exercise, and drugs, which is why medication is often used to manipulate neurotransmitters to control specific behaviors.

The Brain

The brain is the organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. Located in the head near primary sensory organs, it is the most complex organ in the body, containing approximately 15–33 billion neurons. Its primary function is to exert centralized control over the body's other organs.

Brain Structure and Function

• Motor cortex: Controls voluntary movement.
• Broca’s area: Responsible for speech production.
• Auditory cortex: Processes information from the ears.
• Wernicke’s area: Responsible for language understanding.
• Visual cortex: Processes information from the eyes.
• Somatosensory cortex: Processes information regarding touch, pain, temperature, and proprioception.

Hemispheres of the Brain

The brain is divided into two hemispheres:

• Right Hemisphere: Concerned with spatial comprehension, intuition, creativity, emotions, and face recognition.
• Left Hemisphere: Responsible for logic, analysis, and problem-solving.

If a person experiences brain damage in a specific area accompanied by a change in behavior, it can be assumed that the two are related.