Brain Anatomy and Functions

The Brain and Central Nervous System (CNS)

• The brain creates an environment for proper functioning through the CSF.
• The cerebrum is the largest part of the brain, consisting of two hemispheres separated by a median cleft or longitudinal fissure.
• Each hemisphere contains an irregular cavity containing CSF, known as the lateral ventricle.
• The two hemispheres are connected by a large commissure called the corpus callosum.

Structure of the Cerebrum

• The cerebrum is composed of grey matter (cortex) and white matter (internally).
• The surface of the hemispheres show numerous convolutions (gyri) and fissures (sulci) of varying depth.
• The cortex is not uniform in thickness, being thickest in the motor area and thinnest at the occipital pole.

Lobes of the Cerebrum

• The cerebrum is divided into four lobes: frontal, parietal, occipital, and temporal.
• The frontal lobe is responsible for higher intellect, personality, mood, speech, and motor cortex.
• The parietal lobe is responsible for the sensory cortex.
• The temporal lobe is responsible for memory and language, as well as hearing.
• The occipital lobe is responsible for the visual cortex.

Sulci and Gyri

• The gyri assist in locating certain functional areas of the brain.
• The central sulcus is a prominent sulcus on the superolateral surface.
• The lateral sulcus is a deep sulcus on the lateral surface.
• The parieto-occipital sulcus is a sulcus on the medial surface.

Grey Matter and White Matter in the Nervous System (NS)

• In the CNS, the cell bodies of neurons are found in the grey matter, while the axons are seen as white matter.
• In the PNS, the cell bodies are found in ganglia, and the axons are seen as nerves.
• Grey matter is found in the cerebral cortex or nuclei.
• White matter is found in fibre tracts that run in bundles or fascicles.

Cranial Meninges

• The cranial meninges consist of three layers: dura mater, arachnoid mater, and pia mater.
• The dura mater is a durable, double-layered protective cover.
• The arachnoid mater intervenes between the pia mater and dura mater.
• The pia mater is adherent to the brain.

Nervous System (NS) Functionality

• The NS is functionally organized into the CNS and PNS.
• The CNS consists of the brain and spinal cord.
• The PNS consists of somatic sensory, somatic motor, sympathetic, and parasympathetic systems.

Cellular Architecture of the NS

• The two main types of cells in the NS are neurons and neuroglial cells.
• Neurons are responsible for transmitting information, while neuroglial cells provide support and maintenance.
• Structures found in the NS include blood vessels, ventricular systems, and meninges.

Organization of the NS

• The NS is organized into the CNS and PNS.
• The CNS consists of the brain and spinal cord.
• The PNS consists of somatic sensory, somatic motor, sympathetic, and parasympathetic systems.