Brain Structure and Function

The brain is the centre of the nervous system, responsible for coordinating and controlling bodily processes.
The brain is structurally divided into several regions: the cerebrum, cerebellum, and brain stem.
The largest region, the cerebrum, can be divided into two hemispheres with four lobes each: frontal, parietal, temporal, and occipital.
Each lobe is associated with different functions including logic, language, sensory perception, and visual processing.
The cerebellum plays an essential role in coordinating voluntary movements, maintaining posture and balance.
The brain stem comprises the midbrain, pons, and medulla oblongata, controlling vital functions like heart rate, respiration, and digestion.

Key cells in the brain include neurons and neuroglial (or simply glial) cells.
Neurons are the primary type of cell in the nervous system, responsible for transmitting electrical and chemical signals.
Neurons have a cell body (or soma), dendrites, and an axon.
Glial cells, such as astrocytes, oligodendrocytes, and microglia, support neuronal function.

Neural communication relies on the propagation of action potentials and the release of neurotransmitters.
An action potential is an electrical signal generated by the movement of ions in and out of the neuron via the axon membrane.
The arrival of an action potential at the end of an axon triggers the release of neurotransmitters.
Neurotransmitters bind to receptors on the next neuron in the chain, to either trigger or inhibit the propagation of the action potential.

The brain’s structure and functions change in response to experience, a process called neuroplasticity.
During learning, synaptic connections between neurons can strengthen (long-term potentiation) or weaken (long-term depression).
Changes in the number or strength of synapses facilitate memories and new learning tasks.

Diseases, injuries, or substances can damage neurons, disrupting communication and causing neurological and mental disorders.
Neurodegenerative diseases like Alzheimer’s and Parkinson’s diseases cause loss of neurons and synapses in the cerebrum and other brain regions.
Stroke, traumatic brain injury, and brain tumours can damage brain tissue, affecting its functions, causing a host of symptoms and complications.
Addiction to substances like alcohol or drugs alters brain structure and function, leading to potential substance use disorder.