Explain what dead zones are.
A dead zone is a hypoxic area where the level of oxygen is too low for any living organism to live in. One of the most prominent dead zones in the world is in the gulf of mexico, where the Mississippi River meets the gulf of mexico. The reason for this being is due to the amount of fertilizers and chemicals that farmers and industrial companies dump into the river, eventually it accumulates at the mouth of the river where algae begins to grow abundantly. This becomes a problem because as algae decomposes it utilizes the oxygen in the area in order for the decomposing process to occur. This results in oxygen deprivation and essentially it suffocates all the living organisms the more the algae decomposes until it is no longer a hospitable place for living organisms.
What are mnemonics and how do they work? Example?
Mnemonics are a type of technique that are utilized for remembering. It can be letters, ideas or associations that will help in remembering some sort of information. A common type of mnemonics is the method of loci, which relates to locations and places. The ideas is that people remember places that are familiar with so if you associate the piece of information to a familiar place then you can use it as a clue to remember the information later on. For example hippocampus is an organ in the medial temporal lobe of the brain that deals with the long term memory, in order to remember this I think of a hippo in the middle of my high school campus.
The firing of neurons in the human body is an interesting component of biology. Based on what you know about action potentials and the structure of neurons, explain, step by step how a message is sent via neurotransmitters.
In order for a neurotransmitter to send messages, it must first have an action potential. Essentially an action potential is a change in voltage in the membrane. In order for an action potential to occur the stimulus must reach the threshold since action potentials are all or nothing. Depending on which textbook you reference it will tell you that the threshold needed to be reached is either 65 mv or 70 mv. Once the threshold has occurred the signal will be able to travel throughout the neurotransmitter on to another one and then on to another one until it reaches it's destination. In order to understand how these signals are sent so quickly, the structure of the neurotransmitters is essential. The way I remember what a neuron looks like is by thinking about my arm, my fingers are the dendrites, my palm is the cell body and the length of my arm is the axon. When the signal is sent it will travel through all these parts, it will reduce its amount of time in the axon section of the neuron due to the nodes of ranvier. The nodes of ranvier are sections of the axon that are not coated in the myelin sheath allowing the signal to jump from node to node in order to decrease the amount of time it takes for the signal to reach the next neurotransmitter.