Biology half-term homework
What is a reflex arc?
A reflex arc is the neural pathway that causes a reflex action. In animals, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This characteristic allows reflex actions to occur. reflex action is a rapid automatic and involuntary response to a stimulus which is not under the control of the brain.
If we unknowingly touch a hot object, we immediately move our hand away from it. So moving our hand away on touching a hot iron is an example of reflex action as shown below.
Senses hot object
Response pulls hand away
What is a synapse?
A chemical synapse is a small gap, or commonly referred to as a connection, between two cells that allows for the first cell to communicate with the second cell through a chemical signal. These chemical signals are called neurotransmitters, and once they are released by the presynaptic cell, they act on the first and second cell through specialized protein molecules called neurotransmitter receptors.
What is a serotonin And what is its effect?
Serotonin is a hormone that is found naturally in the human brain; it is also found in some animals, including human beings. It is also found in a variety of plant sources, including vegetables, fruits, and mushrooms. Categorized as a neurotransmitter, it is important in transmitting nerve impulses. It is also described as a vasoconstrictor, which is a substance that can cause narrowing of the blood vessels. The amino acid tryptophan is credited with producing serotonin in the body.
The Term Paper on Cell Phones in the Hands of Drivers: a Risk or Benefit?
Cell Phones in the Hands of Drivers A Risk or a Benefit Ariana Laguna English 102 Professor Barnes/Walter 10 December 2012 Outline THESIS: Unless the risks of cell phones are shown to outweigh the benefits, we should not restrict their use in moving vehicles: instead, we should educate the public about the dangers of driving while phoning and prosecute irresponsible phone users under laws on ...
If the brain has a lack of serotonin what can happen?
Low serotonin levels cause intense refined carbohydrate cravings that are very difficult to ignore. In particular, these food cravings trigger impulse eating that is difficult to control with willpower alone. Exercising willpower and determination becomes difficult because your emotions make you feel “What’s the use, even if I lose weight I’ll only gain it back anyway. I’ll always be fat.” You give up because you feel you are fighting a losing battle. Basically, low serotonin levels attack your ability to “just say no”.
The effect of Prozac on the brain?
When serotonin is released from the “sending” nerve cell, the leftover serotonin is normally reabsorbed by an uptake pump. By blocking the uptake pump, Prozac increases the amount of active serotonin that can be delivered to the “receiving” nerve cell. This means that the neurons steep for a longer period of time in the serotonin you already produce. Prozac selectively affects only serotonin which is why Prozac and other similar drugs are called selective serotonin reuptake inhibitors, or SSRIs.
There are other mechanisms as well. The drug blocks the sensor on the axon that tells the cell when enough serotonin has been produced. This causes the axon to release even more serotonin. Finally, over a period of 2-3 weeks, the receiving cell becomes more sensitive to serotonin, and this is the point at which the anti-depressant effect becomes experienced by the patient. It will take several more weeks, however, for the anti-obsessional effects to become completely realized.
The effect of ecstasy on the brain?
How does Ecstasy cause the serotonin (just like prozac does).
This means that the MDMA will be the first thing to get into the axon terminal. Once there, it interacts with the vesicle, causing it to pour it’s serotonin into the synapse. release of serotonin – MDMA enters the serotonin axon terminal by going through the uptake transporters.
The Term Paper on Ecstasy Effects Of Mdma
Methylenedioxymethamhetamine, the compound used in the drug Ecstasy, was developed in Germany in 1914 as an intermediary substance to pave the way to alternative therapeutic medicines. Presently, MDMA is used for a subculture in America and all over the world of "ravers" who spend their weekends taking this unique drug because of its seemingly mind- expanding properties. The truth about this drug ...
Ecstasy interferes with the neurotransmitter that produces serotonin, the brain chemical that helps to regulate mood, memory, sleep, appetite and temperature. While it may have stirred up plenty of confusion in the press about the effects of taking ecstasy on the brain. The problem is that despite years of research on the effects of ecstasy on the brain the findings are still pretty ambiguous. The most consistent results, however, appear to suggest that MDMA, the active chemical in ecstasy, causes slight impairment on tasks of episodic memory and verbal learning.
