08 - Mechanisms of Brain Protection_student

Welcome and Introduction

  • Instructor: Dr. Danielle Brewer-Deluce, PhD

  • Assistant Professor, Dept of Pathology & Molecular Medicine

  • Key courses: Nursing (HTHSCI 1H06), Health Sciences & iBioMed (HTHSCI 2F03), Engineering (HTHSCI 2L03), Midwifery (HTHSCI 1D06)

Lesion Identification

  • Key Questions: Assigned to each seating section.

  • Images referenced to aid in lesion identification.

Mechanisms of Brain Protection & Vascularization

  • Focus on protective mechanisms of the brain and the role of cerebrospinal fluid (CSF).

Identifying Lesions

Specific Symptoms

  • Ptosis: Drooping eyelid

  • Exotropia: Eye deviation causing the eye to appear down and out.

  • Mydriasis: Dilated pupil.

Learning Outcomes

  • Understand key aspects of neuroprotection:

    • Skull & Vertebrae

    • Meninges and Blood Brain Barrier (BBB)

    • Meningeal layers and clinical implications of ruptures

    • CSF flow from production to cerebral sinus

    • Vascularization patterns in the CNS and implications of lesions.

Anatomy of the Eye

  • Structures:

    • Sclera : White outer covering of the eyeball

    • Cornea : Clear front layer, facilitates light entry

    • Lens : Focuses light onto the retina

    • Iris : Colored part controlling light entry

    • Optic Nerve (CN II) : Transmits visual information

  • Fluid Chambers: Vitreous and Aqueous humor respectively fill the back and front chambers of the eye.

  • Layers of Retina:

    • Macula, Fovea (highest visual acuity), Optic Disc (blind spot)

Refraction and Correction

  • Understanding visual impairments such as:

    • Farsightedness and Nearsightedness: Issues with how light is focused by the eye's lens and cornea.

Primary Visual Pathway

  • Pathway from the left and right visual fields through the optic nerves, optic chiasm, thus reaching the visual cortex.

Mechanisms of Neuroprotection

  • Structures Involved: Tentorial notch, tentorium cerebelli, blood-brain barrier, and more protect brain tissue from damage.

Bony Protection of the CNS

  • Skull and Vertebrae serve to protect the brain and spinal cord.

  • Skull consists of:

    • Neurocranium (5 bones): Frontal, Ethmoid, Occipital, Parietal, Sphenoid

    • Viscerocranium (facial bones, 9 total)

Meninges of the CNS

  • Layers:

    • Dura Mater: Tough outer layer

    • Arachnoid Mater: Middle layer with subarachnoid space filled with CSF

    • Pia Mater: Thin innermost layer covering the brain and spinal cord.

Blood Brain Barrier (BBB)

  • Function: A selective semi-permeable membrane that protects brain tissue.

  • Mechanism: Tight junctions between endothelial cells limit diffusion of hydrophilic substances.

Cerebrospinal Fluid (CSF)

  • Roles: Provides cushioning for the brain, maintains homeostasis, and facilitates waste removal.

  • Flow Pathway: From the choroid plexus in the ventricles to the subarachnoid space.

Hydrocephalus

  • Characteristics: Accumulation of CSF in ventricles due to obstruction, poor absorption, or overproduction, often requiring shunting.

Summary Points

  • Neuroprotection involves bones, meninges, and the blood-brain barrier.

  • Understanding blood flow and CSF circulation is crucial for brain health.

  • The interplay between arterial and venous systems is essential for maintaining brain functions.