Flashcards in Module 5.2 Deck (11)
What is the most common cause of brain damage in young people?
In head injuries what actually produces the brain damage?
The rotational forces that drive brain tissue against the inside of the skull or blood clots that interrupt blood flow to the brain
What are the two types of stroke and causes of each? How do they kill neurons?
Ischemia, caused by a blood clot or obstruction in the arteries, and hemmorrhage, caused by a ruptured artery. In ischemia blood isn't getting to the neurons so they lose their oxygen and glucose supplies. In hemorrhage, they are flooded with blood and excess oxygen, calcium, and other chemicals.
What treatment is used immediately following a stroke? What other treatments might minimize the damage from stroke?
Immediately following a stroke, the individual is given tissue plasminogen activator. Other treatments that might minimize damage from a stroke are to block glutamate synapses , cool the brain, or the use of cannabinoids.
What is diaschisis? How might stimulants promote recovery?
Diaschisis is the decreased activity of surviving neurons after there is damage to tother neurons. Stimulants can help recovery by increasing activity in the brain areas.
In the peripheral nervous system, why do crushed (but not cut) axons regrow to the appropriate targets?
Because the myelin on the two sides of the cut may not line up correctly and the regenerating axon might not have a sure path to follow.
Why don't axons in the central nervous system regenerate? How might this lack of regeneration be overcome?
A cut in the nervous system causes a scar to form and this creates a mechanical barrier, neurons on the two sides of the cut pull apart, or glia in the CNS react to brain damage and they release chemicals that inhibit axon growth.
Describe collateral sprouting in your own words.
When axons are lost after brain damage, the cells that lost their axons produce a chemical that tells other axons to make new branches that attach to the empty synapses.
What is devervation supersensitivity?
Increased sensitivity to a neurotransmitter after the destruction of an incoming axon.
What are some sources of sensory input that can give rise to phantom limbs? Explain how reorganization of the brain accounts for the phantom sensations.
Some sources of sensory input that can give rise to phantom limbs are collateral sprouting or increased receptor sensitivity by the postsynapptic neurons. relevant portion of the somatosensory cortex reorganizes and become responsive to alternative inputs.