Alex Di Paola 1/26/17Introduction to Psychology Prof. Gannon 1.)In order to even begin to understandour thoughts and actions, we must first understand the role our biology plays.
More specifically how our neurons communicate with one another. Not all neuronsare the same. Each neuron has a cell body and branching fibers. Bushy dendritefibers receive information and transmit the information toward the cell body.
Then, the axon fiber passes the message through its terminal to various partsof your body. These parts include other neurons, muscles and glands. So, the dendriteslisten to the messages and the axons sends that message to the necessarytarget. In order to understand how neurons communicate, it’s important tounderstand what action potential is. Action potential is the process of aneuron sending a message by firing an impulse. Action potential is also thebrief electrical charge that travels down its axon.
A neural impulse travels atvarious speeds. The speed at which a neuron travels depends on the type offiber. The speed ranges from 2 miles per hour to more than 200 miles per hour.This may sound fast but in comparison to the rate at which electricity ispassed through a wire, the speed is comparably slow. So our ability to react toan event is not instantaneous. Our reaction compared to a computer is a quarterof a second slower. This is pretty interesting because our brain is vastly morecomplex than a computer and yet the computer can process information muchfaster. Neurons are so complex that even with a microscope it would be almostimpossible to tell where one neuron ends and the other begins.
In the past,scientists believed that the axon of one cell fused with the dendrites ofanother in an uninterrupted fabric. Sir Charles Sherrington noticed that neuralimpulses were taking a long time to travel through a neural pathway. This led to the discoverythat there must be a brief interruption in the transmission. Sherrington thenstated that the meeting point between neurons would be called a synapse.
Theaxon terminal of one neuron is separated from the receiving neuron. Thesynaptic gap is what separates them. Santiago Ramon y Cajal was interested inthe near unions of neurons, calling them “protoplasmic kisses”. 2.)When an action potential reaches theterminal located at the end of the axon’s end, it triggers the release ofchemical messengers called neurotransmitters. Neurotransmitter molecules crossthe synaptic gap and proceed to bind to receptor sites on the receiving neuron.Neurotransmitters unlock tiny channels at the receiving site. Electricallycharged atoms then proceed to flow in, exciting or inhibiting the receivingneurons readiness to fire.
The excess neurotransmitters are then drifted awayand are broken down by enzymes. The enzymes are then reabsorbed by the sendingneuron. It’s important to understand how neurotransmitters play an importantrole in their ability to affect our moods, memories and mental abilities.
Acetylcholine is one of the best understood neurotransmitters. It plays animportant role within our learning and memory. Acetylcholine is also themessenger at every junction between motor neurons and various skeletal muscles.3.)In order to take apart theinfluences of environment and heredity, behavior geneticists could use twodifferent types of experiments.
The first would control heredity while at thesame varying the home environment. The second experiment would control the homeenvironment while varying heredity. These experiments may seem impossible butby using identical twins, such experiments become possible. There are severalreasons why identical twins would fit the parameters of these experiments.Identical twins are genetically identical.
Some call twins, “Nature’s own humanclones”. They also share the same conception and uterus and usually have thesame birth date and cultural history. Fraternal twins are developed from twoseparate fertilized eggs. Since both eggs share the same womb, they share aprenatal environment but they are genetically no more similar than any brotherand sister.
Sharing the same gene has been proved to result in sharedexperiences. If one twin develops a disease early on, the other twin has a verylikely chance of obtaining the same disease. To study the effects of genes andenvironments, researchers have studied thousands of identical twins. So as youcan see twins have made great research experiments because of the ability tostudy genetically identical individuals. With the same genetics, researcherscan focus on how there external environment has impacted their development.
Researchers can also compare the effects of the external environment to eachtwin.4.) There are 3 types of majorneurons carry information throughout the nervous system.
The first major typeof neurons are the sensory neurons. The sensory neurons carry messages from thebody’s tissues and sensory receptors inward to the brain and spinal cord forprocessing. The second type are motor neurons.
Motor neurons carry a variety ofinstructions from the central nervous system out to the body’s muscles andglands. The third type are interneurons. Interneurons process informationbetween the sensory input and the motor output . Human complexity exists mostlywithin interneurons. There are billions of interneurons and millions of sensoryand motor neurons. There are several examples to show how sensory neuronsfunction.
One example would be smell/ The sensory neurons which partake in theaction of smelling are known as olfactory receptor neurons. These receptorneurons correspond to the odor molecules in the air. 5.
) Brain plasticity is the brain’sability to modify itself after the brain has been damaged. Some brain damageeffects may vary. Severed brain and spinal cord neurons do not regenerate.Also, some brain functions seem preassigned to very specific areas of thebrain. The text talks about a newborn who suffered damage to the temporal lobefacial recognition areas.
The newborn remained unable to recognize faces. Someneutral tissue can recognize in response to damage. Under the surface of ourawareness, the brain is constantly being altered as it adjusts to newexperiences.
Plasticity may also occur after serious damage. In young children,blindness or deafness makes unused brain areas available for other uses. Forexample, the text talks about how if a blind person uses one finger to readBraille, the brain area dedicated to that finger expands as the sense of touchinvades the visual cortex that normally helps people see. 6.)Genes can either be active orinactive.
Epigenetics studies the molecular mechanisms by which environmentscan trigger or block genetic expression. Epigenetic marks are created by ourexperiences. These are more often organic methyl molecules attached to part ofa DNA strand.
If a markinstructs the cell to ignore a gene present in the DNAsegment, those genes will turn off. Meaning they will prevent the DNA fromproducing the proteins coded by that gene. Epigenetic molecules can be affectedby environmental factors. These factors include diet, drugs and stress. Theseepigenetic molecules regulate gene expression.
