Altered Neuronal Transmission Flashcards
It provide neurons with metabolic support and protection
supporting cells
is the fundamental unit of the nervous system; it has highly specialized functions in impulse transmission
The Neuron
The nervous system is composed of:
▫️CNS (brain and spinal chord)
▫️PNS (spinal and cranial nerves; somatic and autonomic [SNS and PNS] nervous system)
Nervous tissue of the CNS is composed of both:
▫️ white and gray matter
It provides protective and metabolic functions in the CNS:
▫️meningis (dura, arachnoid, pila)
▫️CSF
The spinal nerves are categorized based on their relationship with spinal vertebrae:
▫️cervical, thoracic, lumbar, sacral
Autonomic functions are carried out by:
▫️SNS and PNS
contributes to disability and is the basis for a variety of neurologic disorders.
Neuronal injury
the most common cause of injury to the nervous system, leading to neurologic impairment because of brain, spinal cord, or peripheral nerve injury.
Trauma
It may represent primary or secondary causes of neurologic impairment
▫️Ischemic
▫️excitation
▫️pressure injury
is a group of disorders resulting from damage to upper motor neurons with symptoms appearing during the first few years of life.
Cerebral Palsy
Astrocytes
supporting cell that provide structural support and regulate gases and metabolites in interstitial fluid. Blood brain barrier
Supporting cells in __ (CNS) and ___ (PNS) Myelination
▫️oligodendocytes
▫️Schwann cells
supporting cells for phagocytosis
Microglia (CNS)
supporting cells that line ventricular system to produce, monitor, and circulate CSF
▫️Epebdymal (CNS)
supporting cells for structural support. Help to support cell body they surround it like a helmet.
Satellite (PNS)
in the spinal cord, ____ - efferent motor neurons leaving cord
Ventral horn
in the Spinal Cord, ____ - sensory neurons receiving afferent impulses goes in
Dorsal horn
What are the CNS protection?
▫️cerebrovascular circulation 🔺capillaries, circle of Willis, blood brain barrier ▫️blood-brain barrier ▫️cerebrospinal fluid (CSF) 🔺cushion, provision of nutrients
Peripheral Nervous System Organization?
▫️Somatic
🔺motor and sensory impulses between the CNS and the periphery (cranial nerves and spinal nerves)
▫️Autonomic (SNS and PNS)
Mechanism of Neuronal Injury:
- Traumatic
- Ischemic
- Excitation
- Pressure
Damage to neurons results from the following processes:
▫️chromatolysis
▫️atrophy
▫️neuronophagia
▫️intraneuronal inclusions
is a type of neuron injury: neuronal swelling causing NT death
Chromatolysis
a type of neuron injury: decrease in size (could be from dehydration or lack of O2 where shrinking occurs to reduce workload)
▫️atrophy
a type of neuron injury: phagocytosis and inflammatory responses caused by a dead neuron damaging neighboring cells ➡️ use of microglial cells
▫️neuronophagia
type of injury to neuron: distinct structures formed within nucleus or cytoplasm ex. lead, proteins
▫️intraneuronal inclusions
CNS cellular response to injury:
▫️astrogliosis ▫️microglial nodules ▫️axonal degeneration ▫️axonal regeneration ▫️neuropathy ▫️demyelination
___ increased number of astrocytes causing glial scarring affecting sorround neuronal functioning
▫️Astrogliosis
is a “nodule-like” clustering of microglial cells around dead/dying neuronal cells
▫️Microglial nodules
is caused by delayed nerve conduction and sensory perception
Neuropathy
Closed head injuries:
▫️concussion
▫️contusion
a closed head injury: usually from blow to the head (blunt force trauma) disrupting neurological function and causing LOC
Concussion
is a closed head injury: mov’t of brain w/n cranium causes widespread neuronal damage due to bruising
Whiplash (frontal and occipital bruising of brain)
Contusion
Open head injuries - Skull fructures:
▫️compound
▫️depressed
▫️basilar
Brain structure (dura, meninges, brain tissue) exposed to environment, possible embedding of bone into brain tissue (high risk of infection)
▫️compound (a type of open head injury)
Skull is displaced below level of skull, compressing brain tissue (Affects pressure on brain and blood vessels)
Depressed (a type of open head injury)
fracture at base of skull (often accompanied by loss of CSF through ears/nose)
Basilar (a type of open head injuries)
Traumatic CNS injuries to Spinal Cord Is usually the result of fractures, contusions, or compression of vertebrae typically due to falls, violent sports or activities, MVA.
Most common sites of injury are:
▫️C5-C7, T12, and L1
occurs when there is inadequate perfusion to neurologic tissue, resulting in impaired oxygenation.
Ischemic CNS injury
Focal vs global Ischemia
▫️focal ischemia in the brain is confined to a specific brain region (ei due to stroke or local hemorrhage)while
▫️global ischemia includes larger areas of brain tissue (due to cardiac arrest or significant hemorrhage)
Traumatic injury to peripheral nerves can occur because of the:
▫️crushing or cutting of the neurons
damage to peripheral nerves from traumatic injury manifests with sensory symptoms:
▫️numbness
▫️paresthesia
▫️pain
when nerve trauma is limited to single area, condition such as nerve entrapment and compression may contribute to impaired functional response
🔺typically due to crushing or cutting of neurons, usually in small area
Mononeuropathy
Peripheral nerve damage involving multiple axons is known as ____
🔺generally occur secondary to disease process such as multiple sclerosis, DMII, nutrient deficiency, and toxic agents (arsenic)
▫️polyneuropathy
Pressure on PNS injuries are caused by direct pressure on nerves, or by localized edema. ex ____
▫️carpal tunnel syndrome
Peripheral nervous system motor dysfunction may be the result of peripheral nerve injury that alters reflex circuits. Many causes such as:
▫️Neuro muscular junction (NMJ) Abnormalities
▫️damage in skeletal muscle fibres
▫️SCI (Spinal Cord injury) damaging the corticospinal system or spinal nerve roots
▫️NT excess or deficiencies
PNS motor dysfunction: Movement disorder
▫️ataxia ▫️athetosis ▫️ballismus ▫️bradykinesia/hypokinesia ▫️chorea ▫️Cogwell ▫️Dystonia ▫️hyperkinesis ▫️Tic ▫️Tremor
Neurological Disorders:
- Seizure Spectrum disorder
- Cerebral palsy
- Multiple sclerosis
- Hydrocephalus
- Incomplete Spinal Cord Transection
- Parkinson’s Disease
- Amyotrophic Lateral Sclerosis
- Myasthenia Gravis
- Huntington’s Disease
Generalized seizures:
▫️absence ▫️myoclonic ▫️tonic ▫️tonic-clonic ▫️Atonic
Focal seizures:
▫️simple partial
▫️complex partial
▫️partial seizure w secondary generalisation