WK5: Content Flashcards
What are the results of injury at the cellular level
- Chromatolysis
- Atrophy
- Neuronophagia
- Intraneuronal Inclusions
Chromatolysis
swelling of neuron and dissolution of chromophil substance in neurons
Atrophy
decrease of cell size
Neuronophagia
phagocytosis and inflammatory responses caused by dead neuron
Intraneuronal inclusions
distinctive structures formed in the nucleus or cytoplasm
What are the injury responses of a neuron?
- Neuropathy
- Axonal Degeneration
- Demyelination
Neuropathy
nerves damaged or destroyed disrupting neural communication
Axonal degeneration
breakdown of distal parts of axons caused by necrosis
Demyelination
myelin damage causing interruption in nerve conduction
What are the injury responses of support (glial) cells?
- Astrogliosis
- Microglial nodules
- Ependymal damage
Astrogliosis
- astrocytes proliferate for repair and scar formation
Microglial nodules
immune response, joined with astrocytes to form nodules
Ependymal damage (CSF alterations)
due to infection, hemorrhage of the ventricles
What are the mechanisms of injury in the CNS?
- Traumatic Injury
- Traumatic Brain Injury (TBI)
- Traumatic Spinal Cord Injury (SCI)
- Ischemic CNS Injury
- Excitation Injury
- Pressure Injury
What are the mechanisms of injury in the PNS
- Traumatic Peripheral Nerve Injury
- Pressure Injury
What are the effects of traumatic brain injury?
- Concussion (temporary alteration in function)
- Contusion: (bruising of brain resulting in permanent braind amage)
- Hematoma
- Edema
- Skull fracture
- Increased ICP (Intracranial Pressure)
- Respiratory depression
- Brain hernia
What are the types of traumatic spinal cord injury and their causes?
- Laceration:
- Rip or tear from vertebral fracture, knife, or bullet
- Transection:
- Completely severed spinal cord from penetrating trauma or vertebral fragments
- Contusion:
- Caused by falls or acceleration/deceleration accidents
- Compression:
- Result of crushing force
- Distraction:
- Spinal cord pulled apart (e.g., lap seatbelt during acceleration/deceleration accidents)
- Concussion:
- Violent blow with no apparent damage, but spinal shock may occur, and deficits subside rapidly
What are the two types of traumatic injurys
- closed head injury
- open traumatic injury
Describe a closed head injury
- skull remains intact
- the force of the acceleration impact causes injury to local tissue (coup)
- the deceleration impact leads to injury on the opposite side of the skull (contrecoup)
Describe an open traumatic injury
- injuries involve a break in the skull, exposing brain tissue to the external environment
- increased risk of infection/injury
What are signs and symptoms of increased ICP (intercranial pressure)?
- increased BP
- altered heart rate
- headache
- vomiting
- decreased consciousness
- papilledema
Ischemic Injury
- when there is inadequate blood flow (perfusion) to tissues, leading to oxygen and nutrient deprivation.
Excitation Injury
- when neurons become overly depolarised or hyperpolarised, leading to disrupted nerve signal transmission.
How does excessive glutamate release contribute to excitation injury?
- Increased glutamate release overstimulates neurons, causing over-excitation, which can lead to cell damage and dysfunction.
What severe effects can occur due to excitation injury?
- can cause abnormal posturing, such as decorticate (arms flexed, legs extended) or decerebrate (arms and legs extended)
What is a pressure injury in the brain?
- A pressure injury occurs when increased intracranial pressure (ICP) damages brain tissue, leading to impaired function.
What are the main causes of increased intracranial pressure (ICP)?
- Increased ICP can result from excessive cerebrospinal fluid (CSF), cerebral edema, hemorrhage, or a tumor
Traumatic Peripheral Nerve Injury
- occurs when a nerve is crushed or severed, leading to degeneration of the affected nerve fiber (Wallerian degeneration).
What are the possible mechanisms of peripheral nerve injury?
- distal axonal degeneration
- cell body and axon degeneration
- segmental demyelination
- remyelination
- axon regeneration.
Pressure Injury
- A PNS pressure injury happens when a nerve is compressed, often due to edema
