Brain Organization and Function: Structure, Protection, and Functional Areas

Brain Organization and Function

Overview

The brain is the central organ of the nervous system, located within the cranial cavity. It controls most of the body's functions, including sensation, movement, cognition, and homeostasis.

• Composed mostly of nervous tissue, which includes neurons and neuroglia.

• Contains internal cavities called ventricles that are filled with cerebrospinal fluid (CSF).

• Average adult brain weight: 1250 g to 1450 g.

• Receives approximately 20% of total blood flow at rest, reflecting its high metabolic demand.

Major Divisions of the Brain

Structural Divisions

The brain is divided into four major regions, each with distinct functions:

• Cerebrum

• Diencephalon

• Cerebellum

• Brain Stem

Table: Brain Divisions and Functions

Brain Division	Main Functions
Cerebrum	Performs higher mental functions, interprets sensory stimuli, plans and initiates movement
Diencephalon	Processes, integrates, and relays information; maintains homeostasis; regulates movement and biological rhythms
Cerebellum	Monitors and coordinates movement
Brainstem	Maintains homeostasis; controls certain reflexes; monitors movement; integrates and relays information

Cerebrum

Structure and Function

The cerebrum is the largest part of the brain, composed of two cerebral hemispheres. It is responsible for higher cognitive functions and voluntary actions.

• Functions: Learning, memory, personality, cognition, language, and conscience.

• Roles in sensation and movement: Processes sensory information and initiates voluntary motor activity.

Key Terms

• Neurons: Specialized cells for transmitting nerve impulses.

• Neuroglia: Supportive cells in nervous tissue.

• Ventricles: Cavities within the brain filled with CSF.

• Cerebral hemispheres: The left and right halves of the cerebrum, each controlling opposite sides of the body.

Example

Damage to the left cerebral hemisphere may result in language deficits, while damage to the right hemisphere can affect spatial awareness and recognition.

Additional info:

• The objectives listed in the materials indicate coverage of protective structures (meninges, skull, CSF, blood-brain barrier), formation and circulation of CSF, distribution of gray and white matter, major lobes and functional areas, lateralization, and functions of motor, association, sensory, and limbic areas. These topics are foundational for understanding brain anatomy and physiology.