lecture recording on 24 February 2025 A & P class

Spinal Cord Overview

• Gray and white matter structure resembles an "H" or butterfly shape.

  • Posterior and anterior regions denote dorsal and ventral segments.

Gray Matter

• Contains neuron cell bodies.

• Divided into:

  • Dorsal horns: Sensory functions.

  • Lateral horns: Sympathetic nervous system.

  • Ventral (anterior) horns: Motor functions.

White Matter

• Does not contain neuron bodies; instead, it has myelinated axons.

• Organized into:

  • Dorsal columns: Ascending sensory pathways.

  • Ventral columns: Motor pathways.

  • Lateral columns: Mixed pathways.

Central Canal

• Contains Cerebrospinal Fluid (CSF).

  • CSF is essential for cushioning and transporting nutrients between neurons.

Dermatomes

• Areas of skin supplied by specific spinal nerves.

  • Each spinal nerve corresponds to a dermatome.

  • Important for understanding sensory innervations.

Spinal Cord Regions

• Divided into four regions:

  • Cervical

  • Thoracic

  • Lumbar

  • Sacral

Brain Structure

• Major Brain Regions:

  • Brainstem: Connects spinal cord to the brain and consists of three parts:

    • Medulla Oblongata: Controls autonomic functions (heart rate, breathing).

    • Pons: Bridge between cerebellum and cerebrum, regulates breathing.

    • Midbrain: Contains nerve pathways and controls vision and hearing.

  • Cerebellum: Coordinates balance and fine motor functions.

  • Cerebrum: Largest brain part. Contains:

    • Corpus Callosum: Connects left and right hemispheres.

    • Functionality divided between hemispheres:

      • Right: Creative functions (art, music).

      • Left: Analytical functions (math, language).

Thalamus, Hypothalamus, and Epithalamus

• Thalamus: Relay center for sensory information.

  • Connects sensory pathways to the appropriate cerebral regions.

• Hypothalamus: Controls the pituitary gland and regulates bodily functions (temperature, thirst, hunger).

• Epithalamus: Contains the pineal gland, involved in regulating sleep cycles (produces melatonin).

Cerebellar Anatomy

• Composed of:

  • Gyri: Folds that increase surface area.

  • Sulci: Shallow grooves.

  • Coordinates motor function and balance.

Brain Functionality

• Cerebral Cortex: Governed by gray matter, controls higher functions (thinking, talking, memory).

• Memory Types:

  • Working memory: Temporary storage for immediate tasks.

  • Short-term memory: Can last minutes to days.

  • Long-term memory: Permanent storage.

Meninges

• Protective layers around the brain and spinal cord:

  • Dura Mater: Toughest layer.

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

  • Pia Mater: Innermost layer, closely adheres to the brain surface.

Ventricles and CSF

• Ventricles: Fluid-filled chambers in the brain; involved in producing and circulating CSF.

• Four Ventricles:

  • Two Lateral Ventricles: One in each cerebral hemisphere.

  • Third Ventricle: Midline cavity between thalamus.

  • Fourth Ventricle: Located at brainstem base, continuous with the central canal of the spinal cord.