Cell Types, Injury & Repair, Damage & Death PDF

Cell Types, Injury & Repair, Damage & Death T3 Systems │ CNS Class 1 │ October 2024 Nervous System Review Body’s command centre CNS and PNS Nervous System Review (cont’d) Central Nervous System (CNS) Brain and spinal cord receives, interprets and responds to body tissues...

Cell Types, Injury & Repair, Damage & Death T3 Systems │ CNS Class 1 │ October 2024 Nervous System Review Body’s command centre CNS and PNS Nervous System Review (cont’d) Central Nervous System (CNS) Brain and spinal cord receives, interprets and responds to body tissues Autonomic system regulation Learning, cognition and memory Nervous System Review (cont’d) Peripheral Nervous System (PNS) Outside the brain and spinal cord Includes cranial nerves Intervertebral foramen boundary Nervous System Review (cont’d) PNS (cont’d) Nervous System Cells 1. Neurons 2. Neuroglia 8 7 Nervous System Cells (cont’d) 1. Neurons Parenchymal cells Send signals via ? Nervous System Cells (cont’d) 1. Neurons (cont’d) Synapses Nervous System Cells (cont’d), Neuron Types Nervous System Cells (cont’d), Neuron Types (cont’d) Nervous System Cells (cont’d), Neuron Types (cont’d) Nervous System Cells (cont’d), Neuron Types (cont’d) Nervous System Cells (cont’d) 2. Neuroglia Support for neurons, such as myelination Nervous System Cells (cont’d) 2. Neuroglia (cont’d) Nodes of Ranvier between myelin Nervous System Cells (cont’d) 2. Neuroglia (cont’d) PNS Neuroglia Schwann Cells Nervous System Cells (cont’d) 2. Neuroglia (cont’d) PNS Neuroglia Satellite Cells SATELLITE CELLS Nervous System Cells (cont’d) 2. Neurogia (cont’d) CNS Neuroglia Microglia Nervous System Cells (cont’d) 2. Neuroglia (cont’d) Astrocyte end feet CNS Neuroglia Astrocytes Nervous System Cells (cont’d) 2. Neuroglia (cont’d) CNS Neuroglia Astrocytes (cont’d) Nervous System Cells (cont’d) 2. Neurogia (cont’d) CNS Neuroglia Astrocytes (cont’d) Nervous System Cells (cont’d) 2. Neuroglia (cont’d) CNS Neuroglia Oligodendrocytes Nervous System Cells (cont’d) 2. Neuroglia (cont’d) CNS Neuroglia Oligodendrocytes (cont’d) Nervous System Cells (cont’d) 2. Neuroglia (cont’d) CNS Neuroglia Ependymal (cont’d) Ependymal Cells Nervous System Cells (cont’d) Neuronal Resiliency Labile Cells Continue to replicate throughout life Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Stable Cells Capable of replicating with appropriate stimulus Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Permanent Cells ? Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Neuroplasticity compensates for destroyed neurons Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Cell body must be destroyed to kill a neuron Diseased vs Dying Neuron Damaged axons in peripheral nerves can potentially repair Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Fatal Axonal Injury Peripheral nerve axon damage classified by level of injury Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Fatal Axonal Injury (cont’d) Axonotmesis Axon damaged ? Potential for regrowth Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Fatal Axonal Injury (cont’d) Axonotmesis (cont’d) Wallerian Degeneration followed by axonal sprouting Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Fatal Axonal Injury (cont’d) Neurotmesis Axon damaged Endoneurium and myelin sheath damaged or destroyed Regrowth unlikely Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Fatal Axonal Injury (cont’d) CNS neurons typically ?: Inhibitory molecules Glial scar Less growth-related gene expression Nervous System Cells (cont’d) Neuronal Resiliency (cont’d) Fatal Axonal Injury (cont’d) Retrograde degeneration if CNS axon fatally injured or PNS axon damage too close to cell body Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS Sensitive to O2 reduction and blood sugar variations Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS 1. In Utero Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS (cont’d) 2. Birth-related Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS (cont’d) 3. Fractures/Dislocations of Supporting Bones 4. Compression 5. Direct Trauma Nervous System Cells (cont’d) Coup Causes of Cell Damage/Death in CNS Coup-Contrecoup (cont’d) 6. Concussion, contusion Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS (cont’d) 7. Autoimmune conditions Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS (cont’d) 8. Vascular Lesions  Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS (cont’d) 9. Infection Organism Type Location in CNS Common Bacteria Brain tissue Viruses Brain protective membranes Fungi, Yeast, Spinal Cord Superbacteria parenchyma Spinal Cord Membranes Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS (cont’d) 9. Infection (cont’d) Nervous System Cells (cont’d) Causes of Cell Damage/Death in CNS (cont’d) 9. Infection (cont’d) COVID Effects on the Brain Nervous System Cells (cont’d) Causes of Cell Brain Damage from Mercury Damage/Death in CNS (cont’d) 9. Poisons/ Toxins