Development Of The Brain Flashcards
The development of the brain involves the following processes?
Proliferation Differentiation Migration Synaptogenesis —myelination
Proliferation
Refers to the production new cells/ neurons in the brain primarily occurring early in life
Early in development, the cells lining the ventricles divide
Some cells become stem cells that continue to divide
Others stay where they are or become neurons or glia that migrate to other locations
Differentiation
Refers to the forming of the axons and dendrite that gives the neurons its distinctive shape
The axon grows first either during migration or once it has reached its target and is followed by the development of the dendrites
Neurons differ in their shape and chemical component depending on their location in the brain
Differentiation contd.
Differentiated vs undifferentiated?
How do neurons find their location?
When neurons choose their path
Once differentiated neurons don’t follow other neurons and become what they need to
Undifferentiated neurons follow other neurons
To find their location neurons follow their own chemical markers/ path
—tell them whether they are “hot and cold “
Migration
Refers to the movement of the newly formed neurons and glia to their eventual locations
Occurs in a variety of directions throughout the brain
Occurs via cells following chemical paths in the brain of immunoglobins and chemokines (tell neurons where they are headed)
Synaptogenesis
The final stage of neural development and refers to the formation of the synapses between neurons
Occurs throughout the life as neurons are constantly forming new connections and discarding old ones
Slows significantly later in the lifetime
Myelination
Refers to the process by which glue produce the fatty sheath that covers the axons of some neurons
Speeds up the transmission of neural impulses
First occurs in the spinal cord and then in the Hindbrain, Midbrain, and forebrain
Occurs gradually for decades
Stem cells
Undifferentiated cells found in the interior of the brain that generate “daughter cells” which can transform into glia or neurons
Differentiate into new neurons in the adults hippocampus of mammals and facilitate learning
—we need NEW neurons where we learn new things
Nerve growth factor
NGF
A type of neurotrophin release by muscles that promotes the survival and growth of axons
Neurotropin
A chemical that promotes the survival and activity of neurons
Apoptosis
A preprogrammed mechanism of cell death
Neurons are program to die if not use
What happens during and after maturity to neurons?
During maturity neurons not used are eliminated
After maturity, the most used neurons become dormant and increase branching on axons and dendrites throughout life
