Human Body: Nervous System

The nervous system is responsible for the control of the body and communication among its parts.
It is divided into two main parts: The central nervous system (comprising the brain and spinal cord) and the peripheral nervous system (all other neural elements).
Within the peripheral nervous system, there are sensory neurons which transport information from sensory receptors towards the central nervous system, and motor neurons which carry messages away from the central nervous system towards muscles and glands.
Neurons are the basic units of the nervous system. They consist of cell bodies, dendrites (which receive information), and axons (which send information).
Signals are transmitted along neurons as electrical impulses. These electrical impulses manifest as a difference in charge across the neuron cell membrane, known as the resting potential.
When a neuron is activated, it triggers an action potential. This is essentially a rapid change in polarity across the neuron cell membrane, allowing the signal to be transmitted along it.
Neurotransmitters are chemicals that transmit signals from a neuron to a target cell across a synapse. They bind to specific receptors on the target cell to trigger or inhibit an action potential.
The nervous system allows for the swift and coordinated response to stimuli. It is instrumental in functions such as movement, emotion, cognition, consciousness, and homeostasis.
The nervous system is closely linked with the endocrine system - together, they control and coordinate the body’s responses to changes in the environment.
Disorders of the nervous system can result in a range of conditions, from motor and sensory issues (like paralysis or numbness) to cognitive and behavioural conditions (like dementia or autism).
The brain is split into main regions: the cerebrum (responsible for higher brain functions, like thought and action), the cerebellum (responsible for coordination and balance) and the medulla (which controls automatic functions like breathing).
The nervous system plays a crucial role in maintaining homeostasis: the balance of the body’s internal conditions, such as temperature and blood glucose levels.