All About Nerve Cells

8/30/15

8/31/15

All About Nerve Cells

  What controls our body, actions, and thought? Of course, we answer, "the brain". Yet, how much do we know about the brain, specifically the cells that basically let us control our bodies. 

  Nerve cells are a type of cell known as neurons. Their cell bodies range from 4 microns wide to 100 microns wide (a micron is 1/1000 of a millimeter). They are located throughout the body and the brain. Just in the brain alone there are about 100 billion nerve cells, and some run over a meter long throughout the body.
  There are three basic parts to the neuron: the cell body, the axon, and the dendrites. The cell body contains the nucleus as well as the basic organelles needed to function such as a nucleus, mitochondria, cytoplasm, and other organelles. The axon is like a cable that carries electrochemical messages. The dendrites are nerve ending at the end of a cell and connect with other cells to relay information/ signals. A myelin sheath, a fatty substance, covers the axon to protect the body from the electrical signals being sent.
  Neurons specialize in sending electrochemical signals throughout the body. A stimulus causes a signal to be transported from the cell membrane down to the axon, if the signal surpasses the action potential needed to start the reaction. This then causes potassium and sodium channels to open up as they being to carry the signal down the axon toward the terminal. The myelin sheath speeds up this process as well as stops the ions (K+ and Na+) from being exchanged with the outside environment. Once the signal reaches the end of the axon, the dendrites transfer the signal to the next cell membrane and the cycle continues.
  These cells function throughout the body to carry out these tasks and are classified as nerve tissue. Based on the direction and the type of information that is sent, nerve cells can be classified into different categories. Sensory neurons send information from the sense (nose, eyes, ears, mouth, skin) to the central nervous system. Motor neurons, for example, send signals from the central nervous systems to the muscles and glands. Interneurons send signals between sensory and motor neurons.

Please see pages for works cited.
  

August 24, 2015

Sweetness Lab Response

    In this lab, we tasted different carbohydrates and ranked them in order of their "sweetness". Our goal was to determine how the carbohydrate's structure affected its sweetness. In the end, our group figured out that the monosaccharides and dissacharides were sweeter than the polysaccharides. We concluded that the longer the chain of monomers, the less sweet the sugar was.
    It is interesting how many ways these sugars appear in our everyday lives from food to our body processes (i.e. respiration). Foods such as milk, high fructose corn syrup, vegetables, fruits, and honey all include types of sugars like lactose in milk, fructose in corn syrup and honey, and even glucose and sucrose in fruits and vegetables.
    But then there is the question of how do we even taste sweetness? Can it even be quantified? Although we all taste sugar and sweetness differently, the way the tongue works helps explain how we taste sweetness. According to a informational video by the Smithsonian and an article from the U.S. National Library of Medicine, taste bud receptors do NOT single out individual tastes such as sour or salty, but rather they contain receivers for all 5 tastes. As humans, we tend to favor the salty, sweet, and umami (savory) foods instead of the bitter or sour ones. However, genetics play a factor as well as we each taste things differently than the person next to us, which, in the lab, explains the various numerical rankings that we gave.

The carbohydrates that we tasted. 

Photo by: Jennifer Poo