CNS_Anatomy_&_Function_of_the_Brain.BB (1)

Introduction

The presentation provided by Dr. Richard Ngomba at the University of Lincoln's School of Pharmacy focuses on CNS Anatomy and Physiology, specifically relating to the human brain. The course intends to cover various aspects of brain structure, function, and protective mechanisms.

Main Reading Resources

• Textbooks for the course include:

  • Fundamental Neuroscience (4th Edition)

  • Rang & Dale’s Pharmacology

  • Human Anatomy & Physiology (9th Edition) by Elaine N. Marieb and Katja Hoehn

• These materials are available in the University of Lincoln’s Library for internal use.

Course Objectives

• Identify and describe the main structures of the brain.

• Understand terminology used to describe neural orientations and relationships.

• Recognize protective systems for the CNS, including the meninges, cerebrospinal fluid (CSF), and blood-brain barrier (BBB).

• Explain the formation and circulatory pathway of cerebrospinal fluid.

• Explore relationships between brain development stages and adult structures, including ventricular spaces and major white matter structures.

Orientation Terms in CNS

Understanding directions in the brain is essential for navigation through CNS anatomy:

• Anterior (Rostral): towards the front

• Posterior (Caudal): towards the back

• Superior (Dorsal): above or higher in position

• Inferior (Ventral): below or lower in position

Imaging Techniques

• Magnetic Resonance Imaging (MRI) and CT Scans provide detailed anatomical images of brain structures.

• PET scans and functional MRI illustrate brain function by mapping blood flow or glucose utilization during neurological activities.

Brain Structure Overview

Major Divisions

• Telencephalon: Cerebral hemispheres including cortex and white matter.

• Diencephalon: Comprising the thalamus, hypothalamus, and associated structures.

• Brain Stem: Divisions include the midbrain, pons, and medulla oblongata.

• Cerebellum: Coordinates movement and balances the body.

Embryonic Development

The CNS develops from a primitive neural tube, visible by day 50 of gestation. Key embryological subdivisions include:

• Telencephalon → cerebral hemispheres

• Diencephalon → epithalamus, thalamus, hypothalamus

• Mesencephalon → midbrain

• Metencephalon → pons and cerebellum

• Myelencephalon → medulla oblongata

As development progresses, the forebrain moves towards the brain stem, folding and convoluting to create surface area for neural connections.

Brain Lobes and Features

The cerebrum consists of five lobes:

• Frontal: Involved in decision-making, problem-solving, and motor functions.

• Parietal: Processes sensory information.

• Temporal: Associated with auditory perception and memory.

• Occipital: Responsible for visual processing.

• Insula: Integrates different types of sensory information.

Gyri and Sulci

• Gyri: Elevated ridges of the brain.

• Sulci: Shallow grooves separating gyri.

• Fissures: Deep grooves that separate large brain regions (e.g., median longitudinal fissure).

Cerebral Cortex Functions

• Motor Areas: Includes the primary motor cortex, premotor area, Broca’s area, and frontal eye field.

• Sensory Areas: Comprise the primary somatosensory cortex, auditory cortices, and visual areas, responsible for processing various sensations.

• Association Areas: Integrate sensory information and contribute to higher cognitive functions such as language processing and problem-solving.

Protective Mechanisms of the Brain

Several structures protect the brain:

• Bone: The skull forms the outer protective barrier.

• Meninges: Three layers (dura mater, arachnoid, pia mater) safeguard the brain and enclose CSF.

• Cerebrospinal Fluid (CSF): Cushions neural tissue, reduces weight, and provides nutrients.

• Blood-Brain Barrier (BBB): A selective permeability barrier that helps maintain the brain's stable environment.

Meninges Overview

• Dura Mater: Tough outer layer that contains two layers of fibrous connective tissues, forming dural venous sinuses.

• Arachnoid Mater: Middle layer with web-like extensions, contains the subarachnoid space filled with CSF.

• Pia Mater: Thin, delicate layer that clings tightly to the surface of the brain.

Cerebrospinal Fluid (CSF)

• Production and Composition: CSF is produced in the choroid plexus, circulating through ventricles and the subarachnoid space, consisting of a different protein and ion concentration compared to blood plasma.

• Functions: Provides cushioning, buoyancy (reducing brain weight), protects the CNS, and serves nutritional purposes.

CSF Circulation Pathway

1. Produced in the choroid plexus.

2. Flows through ventricles.

3. Enters the subarachnoid space.

4. Absorbed back into the venous sinuses via arachnoid villi.