Central Nervous System: Functional Anatomy of the Brain

Central Nervous System (CNS)

Functional Anatomy of the Brain

The central nervous system (CNS) consists of the brain and spinal cord, serving as the main control center for the body. The brain is divided into several major regions, each with distinct structures and functions.

• Cerebral Hemispheres (Cerebrum): The largest part of the brain, responsible for higher brain functions such as thought, action, and sensory processing.

• Diencephalon: Contains structures like the thalamus and hypothalamus, involved in sensory relay and autonomic control.

• Brain Stem: Connects the brain to the spinal cord and controls vital functions.

• Cerebellum: Coordinates movement and balance.

Cerebral Hemispheres

Structure and Surface Features

The cerebral hemispheres are paired structures (left and right) that make up the superior parts of the brain and account for more than half of its mass. Their surface is highly convoluted, increasing the area for neural processing.

• Gyri: Elevated ridges on the brain's surface ("folds").

• Sulci: Shallow grooves between gyri ("grooves").

• Fissures: Deeper grooves that separate large regions of the brain.

• Lobes: Regions named after the cranial bones above them (frontal, parietal, temporal, occipital).

Example: The central sulcus separates the frontal and parietal lobes.

Brain Regions and Their Functions

Major Brain Regions

Each region of the brain has specialized functions essential for bodily control and cognition.

• Cerebral Cortex: The outer layer of gray matter responsible for processing sensory information, voluntary muscle movement, and higher intellectual functions.

• White Matter: Deep to the cortex, composed of myelinated fiber tracts that connect different brain regions.

• Basal Nuclei: Deep pockets of gray matter involved in regulating voluntary motor activities.

Lateral and Superior Views of the Brain

Viewing the brain from different angles helps identify the location of major lobes and structures.

• Lateral View: Shows the cerebrum, cerebellum, and brain stem.

• Superior View: Highlights the longitudinal fissure and the arrangement of lobes.

Gyri = folds, Sulci = grooves

Table: Major Brain Regions and Their Functions

Region	Main Structures	Primary Functions
Cerebral Hemispheres	Frontal, Parietal, Temporal, Occipital Lobes	Higher cognitive functions, sensory processing, voluntary movement
Diencephalon	Thalamus, Hypothalamus, Epithalamus	Sensory relay, autonomic control, hormone regulation
Brain Stem	Midbrain, Pons, Medulla Oblongata	Vital functions (breathing, heart rate), reflexes
Cerebellum	Two hemispheres	Coordination, balance, timing of movements

Additional info:

• The central sulcus is a prominent landmark separating the frontal and parietal lobes.

• Gray matter consists mainly of neuron cell bodies, while white matter is composed of myelinated axons.

• The cerebellum is essential for fine motor control and maintaining posture.