Lecture 14: Cell Death Flashcards
What are the many different causes of cell death?
development
trauma
toxins (e.g. alcohol, pesticides, heavy metals)
cerebral vascular disease (ischemic/hemorrhagic stroke)
infectious agents
genetic diseases
neurodegenerative diseases of unknown cause
Where does Pick’s disease cause cell death?
a cause of frontotemporal degeneration
Where does Huntington’s disease cause cell death?
basal ganglia
Where does Parkinson’s disease cause cell death?
damage to neurons that contain melanin
Where does advanced CJD cause cell death?
“mad cow” disease
brain starts to look like a sponge
Where does meningioma cause cell death?
tumor in the meninges
headaches, tingling in fingers
creates pressure on the brain, indentation
What are the two types of cells in the CNS?
neurons and glial cells
What are neurons?
much more valuable type of cell - live on the edge
brain consumes ~25% of total oxygen and glucose in the bloodstream (as high as 50% if required)
neurons use glucose as their primary carbon source
neurons are not replaced in significant numbers
What are glial cells?
regulate health and cell survival in the CNS
dysfunction implicated in disease and injury to CNS
What is “appropriate” cell dealth?
during development more neurons than will be needed are born
gradually “prune off” unused cells
fine tuning connections orchestrated by interactions with the environment (macro and microenvironments)
developmental cell death occurs without tissue inflammation or disruption of surrounding cells
“use it or lose it” principle that involves growth factors and electrophysiological activity
this type of cell death is programmed by the DNA for establishment of the central nervous system and is therefore considered “appropriate”
What is an example of non-programmed necrosis?
non-programmed cell death
What are examples of programmed apoptotic cell death?
apoptosis
anoikis
What state is a normal cell in?
normal cell is in a steady state or homeostasis
What is injury to the cell?
injury is any stimulus bringing changes in cell physiology and/or anatomy - either internal or external
injury can be either reversible or irreversible
What does reversible injury lead to?
adaptation results from the changes in a cell due to reversible injury
What does irreversible injury lead to?
irreversible injury results in cell death
What are the initial characteristics of cell death?
energy failure
disturbance causing lack of oxygen or glucose to cell
What is glutamate-induced neuronal death?
“excitotoxicity”
over stimulation of glutamate activity
excessive stimulation through receptors for neurotransmitter glutamate
caused by excessive release, failure of glutamate uptake mechanisms, exposure to drugs or poison that act just like glutamate (agonist)
too much glutamate activity causes an imbalance of other ions such as calcium and sodium which can result in cell death (messes up homeostatic activity)
will cause both DNS programmed and necrotic cell death
What are reactive oxygen species?
free radicals
will damage cell membranes and intracellular organelles
bounce around and cause damage
will activate DNA programmed cell death mechanisms
What is hypoglycemia?
loss of glucose leads to rapid depletion of cellular energy reserves
will activate DNA programmed cell death mechanisms