Nervous System Flashcards
WHO classifies the most significant mental / neurological disorders into these 4 categories:
- learning and dev disabilities
- neurological disorders
- mental diseases
- substance abuse disorders
What are learning & dev disabilities?
disorders / injuries to NS young, limits development and thus function later in life
genetic, nutritional, infections, toxic expxosures, injury, poverty, multifactorial causes
down syndrome, fragile X syndrome, neural tube defects, thalidomide
What are the features of Alzheimer’s disease & other dementias?
deterioration of intellectual function and other cognitive skills that is severe enough to interfere with social or occupational functioning
AD is incurable, nearly untreatable, most common form of dementia
Explain the biological basis of AD (Alzheimers)
- characterized by deposition of amyloid proteins
- disruption of neuronal cytoskeleton (neurofibrillary tangles from tau)
- however, language systems seem to be preserved
The cytoskeleton consists of 3 main protein polymers. What are they?
- microtubule - microtubule associated proteins like tau get unstable microtubule formation and aggregates of tau proteins fall apart and aggregate/tangled
- Neurofilament / intermediate - vary from cell to cell
- Microfilament - actin
tau proteins in Alzheimer’s disease become abnormally modified, leading to the destabilization of microtubules and the formation of toxic aggregates. These changes disrupt neuronal function and contribute to the progressive cognitive decline observed in Alzheimer’s patients.
How does a buildup of amyloid result in Alzheimers?
- Alzheimers is caused by a build-up of an abnormal config of a protein amyloid
- may cause neurons to produce abnormal intracellular aggregations of tau protein
- tau protein is normally present in neurons where is stabilizes microtubules, in brains producing amyloid, intracellular tau forms aggregates (neurofibrillary tangles) this may cause neuronal death
Which areas are vulnerable and which areas are not (In AD)?
Vulnerable: medial temporal lobe - hippocampus & neocortex affected = memory
Not vulnerable: primary motor/sensory cortex, parental regions, visual cortex relatively unaffected
btw, what is the difference or distinction between a neurological disease and a
mental illness?
It’s largely a historical distinction based on what were thought
to be disorders caused by an “organic process”, such as degeneration or
inflammation (the neurological disorders), and disorders of the mind (mental disorders) due to it not working properly rather than being damaged by some disease process – a software rather than hardware issue. This distinction is not really as valid as it once seemed
Define epilepsy
common brain disorder characterized by 2 or more unprovoked seizures
affects ~ 1% of population (50-70 M worldwide)
Features of seizures
- seizures are discrete events caused by transient, hyper/highly-synchronous abnormal neuronal activity
- may occur in close temporal association w acute stroke, sepsis, or alcohol withdrawal
- associated w loss of consciousness
can be linked to a toxic event
vast majority of seizures have no immediate identifiable cause
Epilepsy is more of a SYMPTOM of a disease than a disease itself. It is divided into 3 categories. What are they?
1) Idiopathic epilepsy (such as childhood-onset absence epilepsy - thought to have a genetic basis) ~ 10%
2) Secondary / symptomatic epilepsy (caused a known central NS injury or disorder, e.g. infection, stroke, traumatic injury) ~ 20%
3) Cryptogenic epilepsy - no clear evidence of an etiological factor ~ 60%
Explain the underlying biological cause of idiopathic epilepsy
Genetic Basis:
Gene Involvement: Many genes implicated in epilepsy encode proteins that play roles in neuronal excitability, ion channels, vesicle trafficking, etc.
Subtle Mutations: Even small mutations in these genes can cause familial epilepsies.
Mechanism of Dysfunction:
Protein Function: The issue is not that the proteins are non-functional, but that there are subtle changes affecting their function.
Neurotransmitter Binding and Ion Channel Function: Minor changes in the affinity for neurotransmitters or the duration of ion channel opening can lead to increased neuronal excitability, contributing to epileptic activity.
Define mental disorders
diseases that affect cognition, emotion, and behavioural control and substantially interfere both with ability of children to learn and with ability of adults to function in their families, at work, and in the broader society. Mental disorders tend to begin early in life and often run a chronic recurrent course.
Male vs Female mental disorders
Males have higher rates of attention deficit hyperactivity disorder,
autism, and substance use disorders;
Females have higher rates of major depressive disorder, most anxiety
disorders, and eating disorders
What does prodromal mean?
preceding the more obvious, diagnosable symptoms of an illness or disease
