4-development, degeneration, and regeneration of the nervous system Flashcards
What does successful brain development require?
-Sufficient number of neurons to be produced.
-Neurons to be in the correct locations.
-Neurons to be connected into appropriate networks.
Describe the development of the embryo.
Describe brain degeneration, and provide some examples.
Brain degeneration involves the loss of neurons/synapses and/or the degradation of the myelin sheath, or the fatty white layer surrounding the axon. It can be large, but focused on a limited region of the brain. There are two types: apoptosis and pruning. Pathological loss is caused by loss of oxygen supply, such as when a stroke occurs, or altered cellular biochemistry, such as someone with Parkinson’s disease. Necrosis, or when mass neuronal death happens from a general loss of cell integrity, can also occur. Unfortunately, the older you get, the harder it is for your brain to repair, or have the ability of plasticity.
What is the difference and similarity between apoptosis and pruning?
Apoptosis happens naturally throughout our life, while pruning happens only in specific stages of development. However, both involve neurons dying.
Describe the difference between how damaged neurons can repair in the CNS v.s. PNS.
In the CNS, the extent of repair/recovery is limited. While for the PNS, it’s possible if the cell bodies remain intact.
Describe neuronal replacement.
Humans can go through neurogenesis, which is the ability of stem cells to divide in order to form new neurons. However, this ability is severely limited, and also could be insufficient to counteract loss due to neurodegenerative disease. There are some regions that have better capacity for neurogenesis.
