Vocabulary/Concept Vitalizer

Daniela Elliott

Blog 2
(Introduction and Chapter 1, pages 1-42)
 

1. Neurons – an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Neurons are the core components of the Nervous System which includes the brain, spinal cord and peripheral ganglia. 

2. Glial cells – are non-neuronal cells that maintain homeostasis (a stable, constant environment), form myelin and provide support and protect the brain’s neurons. Glial cells have four functions: to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy pathogens (infectious agents such as a virus, bacteria or fungus) and remove dead neuron.

3. Myelin or Myelination – an electrical insulator, meant to resist the flow of electrical charge.  Myelin forms a layer, called the myelin sheath, around the axon (a long slender projection of a neuron, that conducts electrical impulses away from the neuron’s cell body) of a neuron.  Myelin is an outgrowth of a glial cell and is essential of the proper functioning of the nervous system. Myelin is first produced in the 14^th week of fetal development, myelination occurs quickly during infancy and it does not stop until the adolescent stages of life.

4. Congenital Adrenal Hyperplasia, CAH 

refers to a genetic disorder of the adrenal gland and, is the most common Autosomal Recessive disorders. The adrenal glands help keep the body in balance by making the right amounts of hormones, such as Cortisol, Aldosterone, and Androgen.  People with CAH lack an enzyme needed by the adrenal glands to make enough of the hormones Cortisol and Aldosterone and instead make too much Androgen. Androgen is a steroid hormone that stimulates or controls the development and maintenance of male characteristics; including male sex organs and the development of male secondary sex characteristics; it causes male characteristics to appear early or inappropriately in females.  CAH is an autosomal recessive disorder, meaning that a recessive gene is located on one of the Autosomes (chromosome pairs 1through 22, see picture). “Recessive” means that two copies of the gene are necessary to have the trait or disease; one inherited by the mother and the second is inherited by the father.  When a male and female “carrier” of the recessive gene have a child it can be passed on to the child and it is usually is a complete surprise.  About 1 in 10,000 to 18,000 children are born with CAH.

5. Gray Matter vs. White Matter – Gray matter consists of neuronal cell bodies, neuropil (a region between neuronal cell bodies in the matter of the brain and spinal cord), glial cells and capillaries (the smallest of a body’s blood vessel).  The gray color comes from the capillary vessels and neuron cell bodies.

White Matter consists of myelinated axons.  Axons are long, slender projections of a neuron that conduct electrical impulses away from the neuron’s cell body.  The function of white matter tissue is to allow messages to pass through different areas of gray matter. The white color is due to the myelin that surrounds the axons; the myelin which is an electrical insulator assist in allowing messages to pass quickly from one place to another.  If ever there is damaged white matter, the brain can find “alternate routes” in which to pass messages through. Although it is disputed, gray matter is said to peak in development in a person’s twenties, while white matter is said to peak in development during the middle ages.