Central Nervous System - Physiology and Anatomy - Lecture Slides, Slides of Physiology

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Medulla oblongata Cerebellum

Diencephalon:

Cerebrum

Brain stem:

ThalamusEpithalamus HypothalamusPineal gland

Midbrain Pons

Spinal cord

Pituitary

Embryonic Development

• Neural plate forms from ectoderm
• Neural plate invaginates to form a neural groove and neural folds

Embryonic Development

• Neural groove fuses dorsally to form the neural tube
• Neural tube gives rise to the brain and spinal cord

Embryonic Development

• Primary vesicles give rise to five secondary brain vesicles - Telencephalon and diencephalon arise from the forebrain - Mesencephalon remains undivided - Metencephalon and myelencephalon arise from the hindbrain

Embryonic Development

• Telencephalon → cerebrum (two hemispheres with cortex, white matter, and basal nuclei)
• Diencephalon → thalamus, hypothalamus, epithalamus, and retina

Effect of Space Restriction on Brain

Development

• Midbrain flexure and cervical flexure cause forebrain to move toward the brain stem
• Cerebral hemispheres grow posteriorly and laterally
• Cerebral hemisphere surfaces crease and fold into convolutions

Figure 12.3a

Metencephalon

Anterior (rostral) Posterior (caudal)

Mesencephalon Diencephalon Midbrain Cervical

Spinal cord

Flexures Telencephalon Myelencephalon (a) Week 5

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Ventricles of the Brain

• Connected to one another and to the central canal of the spinal cord
• Lined by ependymal cells

Ventricles of the Brain

• Contain cerebrospinal fluid
  • Two C-shaped lateral ventricles in the cerebral hemispheres
  • Third ventricle in the diencephalon
  • Fourth ventricle in the hindbrain, dorsal to the pons, develops from the lumen of the neural tube

Blood-Brain Barrier

• Composition
  • Continuous endothelium of capillary walls
  • Basal lamina
  • Feet of astrocytes
    • Provide signal to endothelium for the formation of tight junctions

Blood-Brain Barrier: Functions

• Selective barrier
  • Allows nutrients to move by facilitated diffusion
  • Allows any fat-soluble substances to pass, including alcohol, nicotine, and anesthetics
• Absent in some areas, hypothalamus, pitutary, pineal body and vomiting center

Cerebral Hemispheres

• Surface markings
  • Ridges (gyri), shallow grooves (sulci), and deep grooves (fissures)
  • Five lobes
    • Frontal
    • Parietal
    • Temporal
    • Occipital
    • Insula

Cerebral Hemispheres

• Surface markings

• Central sulcus
  • Separates the precentral gyrus of the frontal lobe and the postcentral gyrus of the parietal lobe
• Longitudinal fissure
  • Separates the two hemispheres
• Transverse cerebral fissure
  • Separates the cerebrum and the cerebellum