Sheep Brain Dissection Lab

Question 1:

Labels of the anterior, posterior, cerebrum,
cerebellum, and brain stem

My drawing of the picture above

Question 2:

Question 3:

Myelin helps to insulate our nerves to decrease the time that messages can be processed.

Question 4:

Labeling the thalamus, optic nerve, medulla oblongata,
pons, midbrain, corpus callosum, and hypothalamus

My drawing of the picture above

Question 5:

Question 6:

A cross sectional cut of the cerebrum

My drawing of the picture above

Relate and Review:

For this lab, we dissected the brain of a sheep, and identified the different parts that we were able to uncover while doing it. First, we labeled the anterior and posterior of the brain and the cerebrum, cerebellum, and the brain stem after attempting to remove some of the meninges.  The brain was then cut longitudinally in order to see some of the myelination of white vs. gray matter, and we labeled the thalamus, optic nerve, medulla oblongata, pons, midbrain, corpus callosum, and the hypothalamus, before cutting the cerebrum in half once more to reveal further details on the differentiation of gray and white matter. In this lab, we were also tasked with finding the functions of each of the parts that we labeled on the heart, and in this way, were able to learn both the anatomy and the physiology of the parts of the brain. Like the Sheep Eye Dissection Lab, the association of what everything does while analyzing the physical characteristics of certain parts helped me really understand how the parts of the brain work together to make us the way we are.

Sheep Eye Dissection Lab Analysis

For this lab, we were able to dissect a preserved sheep's eye in order to learn more about the structures of the human eye. Throughout the lab, we were tasked with finding certain aspects of the eye while dissecting, and in the following picture, I was able to define the parts mentioned.

As for the order that light travels through the eye, light passes through the cornea and the aqueous humor, where it then enters through the pupil. The cornea mainly serves to protect the eye, while the pupil is the hole in the center of the iris that lets light into the eye. The iris, or the colored part of the eye, expands and contracts, controlling the size of the pupil accordingly in relation to the amount of light in the room. After passing through the pupil, light goes through the lens, and then goes through the vitreous humor to to hit the retina, where the image is then sent through the optic nerve to be processed in the brain. Sheep and other animals have a layer of tapetum lucidum to help them see better in the dark, and like us, have a choroid layer to absorb reflecting light in the eye. The sclera is the chute of the eye, and is tough in order to further protect the eye; attached to said layer are accessory muscles that contract and stretch to control eye movement.

Pink Brain Blue Brain: Nervous System Power Reading

For our Nervous System Power Reading Activity, I chose to read the book Pink Brain Blue Brain by Lise Eliot Ph.D. because it interested me in the true differences between the sexes; are boys and girls truly as different as we seem? If so, what about the makeup of our brain makes us unsimilar? I chose to read the first chapter, "Pink and Blue in the Womb", to explore these questions. This chapter mainly focused on how and when males and females differentiate while still unbirthed, and what exactly the porcesses were that controlled the formation of who we know as girls or boys. 

Although the sex of one's child is often the most prominent thing existing in the minds of future parents, the actual differentiation physiologically is only put into play after the first 6 weeks, and the only way to determine whether zygotes have been created with XY chromosomes or XX chromosomes is to use take a single cell from the 8 cell cluster and test it(PGD) or predict X and Y carrying sperm through a technology called Micro Sort(which uses the size difference between the two types of sperm to control the creation of female/male zygotes). Ethicists have long since argued the morality of choosing and discarding embryos of certain sexes, which is common in multiple countries, but even though laws have been erected to restrict sex selection, the only real way to combat such problems would be to raise the social standing of women(as female embryos are often discarded the most in such countries). Eliot then goes through the activations of sex such as the SRY and DAX1 parts of DNA as well as certain hormones like testosterone and AMH(but not estrogen, since it only impacts girls and boys after birth). Connections to how boys and girls define themselves due to environment vs. nature are also made, as the author addresses different cases where genetically born females or males classified themselves differently due to certain disorders, and genetically mutilated individuals were raised as contrasting sexes for a variety of reasons. The main point that the author makes is that although the psychological differences in girls and boys may look miniscule, the raising of both sexes needs to reflect those differences to create the best of every child.

This reading definitely relates to our class because it branches throughout the different systems of the body(reproductive, endocrine, and nervous) and explains exactly what hormones, parts of the brain, and parts of our DNA control different functions, and the impact that they have on the human body. I can relate all of these findings to the idea that "form fits function" because they really do in terms of creating a new human being; the reason that our bodies produce greater or lesser amounts of certain things and create different structures in male and female bodies is truly due to the different functions necessary in each body.

"A Woman Perpetually Falling..." by Norman Doidge, M.D.

The article that we were tasked with reading for homework was, yes, about a woman who was always falling without outside stimuli, but more importantly about the findings of Paul Bach-y-Rita in succeeding to treat the patient in an era when this was believed to be impossible. Cheryl, the patient who suffered from the lack of function in her vestibular apparatus that controls balance within the body, was able to undergo a nearly complete rehabilitation in her vestibular sense thanks to the "training" from Bach-y-Rita's innovative machine that taught her brain's healthy tissue to take on the job of vestibular function. This breakthrough essentially disproved the widely popular localization theory of neurology and assisted in Bach-y-Rita's goal of employing the brain's natural plasticity to rehabilitate and treat patients of all kinds of their afflictions.

Up until his pioneering idea about plasticity in the brain became solidified in scientific theory, the explanation for how the brain worked had long been established as "localization", or the idea that a brain has specific parts that have specific functions to help us control our body as a whole, which perpetuated the belief that once a part of the brain was in dysfunction or even missing it could never be replaced, and the patient would be a lost case. Bach-y-Rita was determined to reevaluate the way neurologists and scientists handled the rehabilitation of patients with various dysfunctions of the brained thus conducted one of many tests with the intent of assisting those who were a "lost cause" due to the impact of the localization theory.

One quote that I found to be informational and interesting was that "to decode theses skin sensations and turn them into pictures...the brain has to learn something new, and the part of the brain devoted to processing touch has to adapt to the new signals". The author was talking about how the type of receptor used by the blind(in this case, their touch with a cane) does not matter as much as the way that the brain responds and uses those signals to assist itself. I found this interesting because I had always wondered how canes help the legally blind "see", and Paul Bach-y-Rita was able to support how instead of memorizing the array of things in a room, they are able to orient themselves by teaching their brain to read the signals of touch for vision.

Another quote that really hit home for me was when Doidge mentions, "[Bach-y-Rita] began to conceive of much of the brain as "polysensory"--that its sensory areas were able to process signals from more than one sense". This was really cool to me because I did know how taste and smell were related to each other, but the idea that senses such as sight and hearing could also be associated was really novel.

Finally, the ending sentence of this reading that concludes,"[Nature] has given us a brain that survives in a changing world by changing itself". This quote really resounded with me because of how nicely it summarized the entire idea of this reading, which is how the brain can adapt to fit different conditions in people who have various changes in the makeup of their brain and the effectiveness of its parts. The brain is able to exchange functions between parts if needed, as also seen in the "Woman With a Hole in Her Brain" reading that we had read previously.

The Clay Brain

In class, we made a models of the brain with Play-Doh, and then labeled them to represent different parts of the brain. This was made on a piece of cardboard, and the end result was a colorfully labeled brain(seen from both the left hemisphere along the sagittal plane and the right cerebral hemisphere) that we could use to help us remember the different parts of the brain. Below are images of our work.

Composting to Combat Climate Change

For this semester, we are going to be tasked with a new project: 20 Time. 20 Time is a project where we as individuals will work towards solving a problem that we, or the world, have, by spending 20% of our time in this class working towards achieving that goal. When brainstorming what exactly to do for my project, I started to question, "What has been bothering me in my life lately, and what can I do to change that?". I settled on the reoccurring guilt that I had for the food scraps that my family had to throw away in more plastic bags that would end up staying in landfills pretty much forever. Therefore my topic for this project will be reducing the amount of greenhouse gases in our atmosphere(specifically methane) to try and "combat climate change" by reducing the amount of organic wastes that go into our landfills.

Seeing as certain people in society today try to disclaim the impact that we as humans have on the environment in general, I wanted to bring this issue to the forefront and demonstrate ways of helping this problem by establishing my own system of composting and sharing some results of what I have found along my journey. "How does composting exactly relate to climate change?" one may ask. Well, by creating a compost system for biodegradable items, you can take out the amount of "organic waste"(or waste originating biologically) that goes into landfills and decomposes anaerobically to create the greenhouse gas methane. Not only does it help take greenhouse gases out of the atmosphere, but composting can also be used for better water retention in the soil and most obviously, for enriching gardens.

My goal by the end of this project will be to learn more about composting (enough to share with my family and the class to encourage them to start their own compost bins), have a fully functional example that I can show to the class by the end of the semester, and be able to use the compost to possibly create a garden of some sort at home. The way that I will measure my progress for this project will be through my blog, where I will be updating anything from recent contact that I have made with with various organizations or experts, to calculations on how much greenhouse gases I have taken out of the atmosphere, to pictures that document the process of my composting journey. Moving forward, I plan to have figured out what type of compost bin I will be creating, attain the necessary materials to build it, and start building by the time I post again(approximately 2 weeks or so).

"The Woman With a Hole in Her Brain"

The article that we were tasked with reading, "The Woman With a Hole in Her Brain", is about a recent discovery of a woman in China who has lived without a cerebellum in her brain for 24 years, and only suffered from minor complications and defects as a result. Instead of having a cerebellum as she should at the near the base of her head, cerebral spinal fluid had filled in the gap, and she became one of 9 people to have been miraculously able to survive a entirely without their cerebellum, and to adulthood nevertheless. The uniqueness of this discovery only further shows how adaptable the brain is; despite missing over 50% of the neurons a normal person would from her lack of a cerebellum, she has still managed to survive to the age of 24 and live to tell the tale. The cerebellum is often credited with controlling voluntary movement and balance, which may explain her unsteady grasp on walking and the dizziness and nausea that sent her to the hospital, but the comparable negligence of these problems only proves how elastic the brain can be when taking over for a missing part. This relates to the transfer of functions of another organ in our body, the spleen, which when damaged or removed, can easily pass the baton of salvaging, storing, and repurposing blood to red bone marrow or the liver.

If one's parietal lobe was missing instead of their cerebellum, there would obviously be very different symptoms than the ones that the woman described in the article had. The parietal lobe of our cerebral cortex is in charge of sensations felt by the body, and controls the reactions that we have to our environment. Inside the parietal zone, there is a vital part of our brain called the somatosensory cortex, which receives sensory input from the sensory nerves located all across the body, and on the other side of it, the motor cortex outputs motor nerves to control actions taken in response to the sensory input. I highly doubt a person would be able to survive, or at least die extremely early into their lifetime, without a parietal lobe, because without the neurons of the somatosensory cortex, no sense of touch would be able to protect us from the dangers of the outside world, and the possibility of one's motor cortex(that controls how our body reacts) being damaged would also be extremely high. People without a parietal lobe would be unable to process physical feeling whatsoever, and that is something that most likely cannot be replaced or take over by one of there other lobes or parts of the brain.