Human Brain Structure and Functions

The Human Brain

• The human brain is the largest, most complex, and highly specialized organ in the body, comprising approximately 100 billion neurons.
• The brain consists of specialized areas that work together to perform various functions.
• The cortex, the outermost layer of brain cells, is responsible for thinking and voluntary movements.
• The brainstem, located between the spinal cord and the rest of the brain, controls breathing and sleep.
• The basal ganglia, a cluster of structures in the center of the brain, coordinate messages between other brain areas.
• The cerebellum, located at the base and back of the brain, is responsible for coordination and balance.
• The cerebrum, the largest part of the brain, is crucial for the learning process, as it is the site of higher-order functions such as memory and reasoning.

Brain Regions

• Occipital lobes are responsible for sight, hosting the brain's visual processing system.
• Temporal lobes are involved in hearing, language, and memory.
• Frontal lobes are responsible for motor function, reasoning, abilities, problem-solving, and judgment.

The Neuron

• A neuron is the basic unit of the nervous system, a specialized cell designed to transmit information to other nerve cells, muscle, or gland cells.
• A neuron consists of:
  • Cell body: the cell's life support center
  • Dendrites: receive messages from other cells
  • Axon: passes messages away from the cell body to other neurons, muscles, or glands
• A neural impulse is an electrical signal that travels down the axon.
• The myelin sheath covers the axon of some neurons, helping to speed up neural impulses.
• Terminal branches of axons form junctions with other cells.

Types of Neurons

• Sensory neurons (afferent neurons) transmit impulses from sensory receptors toward the CNS (Central Nervous System); mostly unipolar.
• Motor neurons (efferent neurons) transmit impulses from the CNS toward muscles or glands; mostly multipolar.
• Interneurons (association neurons) transmit impulses between sensory and motor neurons; mostly multipolar.