Owl Pellet Lab

In our Owl Pellet Lab, we were given an owl pellet to pick apart and needed to identify exactly what kind of animal(s) were part of this particular owl's diet. In my lab group, we found multiple bones and even skulls within the owl pellet, as documented by the pictures on the bottom, and even were able to identify a few of the bones that we as humans shared with these organisms.

We were able to find an assortment of animal bones

An animal's femur, pelvis, lower jaws, and other assorted bones

Upon uncovering all of the bones in the owl pellet, I hypothesized that one of our animals was a pocket gopher, due to certain characteristics of the skull that we observed. From the owl pellet that we got(which was 6.35 g, 45 mm long, and 33 mm wide), we had dug out a skull which was 36 mm long and 21 mm wide, with accompanying mandibles 16.5 mm in length and 3.7 mm in width. This fit in with the typical characteristics of pocket gophers(which have skull lengths of 30-42 millimeters), and although there were some discrepancies in the supposed mandible length(the ones that we found were significantly smaller), that can be attributed to the gopher being eaten prematurely. Additionally, the teeth of the skull were observed to be sharp and pointy, and have separate roots, which is one other characteristics that pocket gophers and voles share. Lastly, the shape of the skull did resemble that of a typical pocket gopher(as seen from the packet), which further solidified my suspicions that the animal we were dealing with was a pocket gopher.

The teeth of the skull were sharp and had individual roots

The skull looked almost exactly like the picture in the packet

As for ways that the animals were similar and different to our own human anatomy, the animals that we discovered had similar femurs, vertebrae, and scapulas as humans. The bones were surprisingly identifiable due to their similarity to human features in our own anatomy. In the scapula specifically, both shoulder blades in rodents and in humans have a fan-like shape, which made it easy to find. Things that differed from human anatomy were definitely the skull(and the teeth as accessories), the pelvis, and the mandible. The differences in the mandibles was most prominent, as humans only have one large lower jaw, while rodents seem to have 2.

The scapula looked a lot like humans' due to its similar shape

Rodents tend to have separated mandibles, not like humans

Learning the Framework

So far, I have been researching more and more about the topic of composting, and gathered numerous sources detailing exactly what types of compost there are and the characteristics of different compost bins. Although composting may seem self-explanatory on the surface, there are actually a lot of layers(no pun intended) involved with creating a successful system of decomposition. Just by researching about the different ways to construct holding units, a new world of information was opened up to me about which types of compost bins were most efficient(worm composting and turning units), how to choose a compost bin most suited to your abode, and whether or not turning the compost would make a difference. From this plethora of information I settled upon a plan of building a holding unit, the one which my resources hinted would require the least amount of work and delicacy, as long as I was able to provide at least an open, flat space of 3 ft x 3 ft x 3ft(which is able to fit in my back yard). I managed to find a plan as well for the construction of various types of holding units, which you can see for yourself here.

Next on my list was actually learning about what I should and should not compost, and how exactly to make the best possible environment for nature to do its work. Compost(at least in a holding unit that I plan to build) should be at least 3x3x3 feet in volume in order to properly hold in heat to speed up decomposition and keep pathogens away from the pile. The order of placing biodegradables should be first a layer of "browns"(dry, carbon ingredients) right above the ground, followed by a layer of "greens"(wet, nitrogen ingredients), alternating back and forth until a height of 3 feet is reached. Brown materials include any sort of dry yard waste like leaves and branches, which my house has plenty of due to our abundance of oak trees around, and green materials are things like food waste(but NOT including animal products of any sort) and yard clippings. At this point, I realized that I should plan to create a separate kitchen container for the green items that I wish to compost and separate out the things that need to be thrown away, so I included that in the general plan that I wished to follow. For some really interesting and important information concerning how to compost properly, you can refer to this resource for help.

Over the time that I have started working on my 20 Time project, I learned a number of things about myself, one of which was that it was hard to convince myself to stick to goals I had for a certain week when more pressing schoolwork was to be done. I had set a goal in my first 20 Time post to start building a compost bin by my next update, and I have not yet been able to accomplish this. Additionally, things that I struggled with during these first couple of weeks has been being out of town for a number of days, restricting my ability to get any work done on a project that is mostly material in nature. There was also the difficulty in doing much work during the allotted time in class besides research, because the majority of my project involves actually building a compost unit and composting at home, which I clearly cannot do at school. To overcome these obstacles, I will try to work more on my project at home through better planning of when to divide the work amongst my other homework, and trying to catch up over the upcoming break.

As for the next steps in my project, I am hoping to accomplish all of the steps I have listed previously and really start composting by the time of my next post, and detailing my findings through the audience on my blog to encourage others to join me in trying to reduce organic waste.

Reflexes Lab

In this lab, we learned about the various reflexes that we have in the body. As we know from learning about neurons, a reflex is the shorter pathway of certain reactions so that instead of firing signals all the way to the brain and back to the mentioned area, it first straight from a sensory neuron to the spinal cord, where it then bounces back to immediately signal mortar neurons to enact a certain response, oftentimes without us knowing it. Therefore, we sent out to find these reflexes and test them out for ourselves, with the photo pupillary, knee jerk, blink, and plantar reflexes, along with the general test of reaction time. All of these tests showed certain behaviors that occurred without our control, relating to the entire purpose of having reflexes which protect us by not sending signals all the way to the brain.

My eye in normal light

My eye once the flashlight was shown in my eye.

The first reflex we tested was the photopupillary reflex, which is supposed to make the pupil smaller in response to intense light. We tested this by closing both of my eyes and shining a flashlight into one, while the other while the other remained in the dark, and found that this reflex did happen(as seen from the photo evidence). This reflex worked because the sensory neurons detecting light(photoreceptors) only had to send a message up to the spinal cord, where it then bounced back to stimulate the ciliary body of the iris to contract in response.

The second reflex was the patellar, or knee jerk, reflex. Our knee is supposed to flinch or jerk outwards in response to a hard hit at the knee, and sure enough, after a test of this reflex, my knee did move without my intention. This reflex worked because the motor sensors in my knee were routed only to the spinal cord, after which the message to kick the leg was sent immediately through the motor neurons without my intention. Afterwards, we tested the reflex after doing 30 squats, and the reflex was less observed, due to the fatigue in  my muscles preventing the reflex from occurring super quickly.

The blink reflex was the next to come(in which we are supposed to blink in response to an oncoming object), and the test in this lab involving it included throwing a cotton ball at my eye with plastic wrap in front of my face. The sudden missile aimed at my face induced me to blink(uncontrolled by me whatsoever), showing that when unexpected things happen our reflexes really do help avoid disaster. Like all of the other reflexes, the blink reflex was induced by the quick timing of sensory neurons, the spinal cord, and motor neurons contracting the eye.

The plantar reflex, or the reflex in which your toes contract with the uncomfortable sensation of having a pen dragged up the sole of the foot, was unfortunately not observed in my test. A possible reason for why the reflex didn't occur in me could be that I was already thinking and anticipating the pen to go up my foot, so the surprise factor did not work as well as it should have.

Lastly, the reaction time test that we conducted was about dropping a ruler between my fingers and seeing how long it took for me to catch it. In the data table, below, you can see that my average reaction time was 0.28 seconds, which set the basis for the second test that we did.

This time, we would be testing the same thing but with the distraction of texting in our other hand, and, as expected, my reaction time was slower than it was before, and the average time was 0.33 seconds. This occurred most likely because the brain was so preoccupied with texting that it was unable to see the yardstick as quickly, and the sensory neurons in turn started the reflex to grab later than before.

Unit 6 Reflection

This unit was about the nervous system in its entirety, and some key themes and understandings were that the brain, although specialized to some extent, can be adapted to new environments and situations in order to better serve the body, and communicates within itself to divide up the work that needs to be done; dysfunctions of the brain are able in many ways to teach us how the brain normally works; and lastly, that the brain needs to be able to work with many other parts of our nervous system in order to truly function at its best.

The Clay Brain

We first started off by learning about the main parts and functions of the brain, the center of our nervous system. The brain is structured from bottom to top by the spinal cord, hindbrain, midbrain, and forebrain, and the closer parts are to the spinal cord, the more basic its movements and functions are. Then there are the parts of the brain, which include the brainstem(comprised of the medulla oblongata, pos, and midbrain); the cerebellum, which controls the body; the thalamus, which sorts data and sends it where it needs to go; the hypothalamus, which maintains homeostasis; the posterior pituitary, which sends out hormones; the cerebrum, which is in charge of integration; and the cerebral cortex, divided into 4 lobes and controls higher function thought and action. Those four lobes are the frontal lobe, which is involved in speaking  and is the "executive; the parietal lobe, in charge of sensation; the occipital lobe, in charge of vision; and the temporal lobes, which include auditory areas. As seen from the article "A Woman With a Hole in her Brain", loss of a certain part of the brain can result in a lack of ability to perform functions that that part of the brain does. The Sheep Brain Dissection also documents our journey in learning about the anatomy of the brain, as well as the Clay Brain.

We next learned how the brain works together to communicate and divide up the work amongst its various different parts. the whole idea of brain lateralization is that the brain "divides and conquers" when it conducts neural functions and cognitive processes between the right and left hemispheres of "A Woman Perpetually Falling". Other important characteristics of the brain are sensory areas, which contain the homunculus(the perception that your brain has of your body in accordance to the sensitivity of various parts of the body), and motor areas, which control muscle movement(where the right and left hemispheres come into play again).
the brain to make processes more efficient. The two sides(which control opposite halves of the body under a contralateral division of labor)communicate through the corpus callosum that connects the two. Contrary to this school of thought is the idea of brain plasticity, where parts the brain are able to take on functions of their missing or dysfunctional neighbors because the brain adapts and evolves in different environments constantly; this can be evidenced by the examples found in the reading

My Senses graphic organizer

Th mechanics of senses were discussed next, and we learned about special(or organ-specific) and somatic(or body) senses, which are received by receptors of all types. Sensory adaptation is the occurrence where our receptors are exposed to stimulus for so long that you no longer receive the message. The main specific senses were discussed, such as sight/vision, hearing, smell, and taste, and the corresponding organs, receptors, and sensory cells were identified as well. dissected a sheep eye in order to learn more about how light travels through the eye, and the functions of the different parts of the eye. Dysfunctions of sight include myopia(near-sightedness), hyperopia(far-sightedness), glaucoma, and cataracts; for hearing a choclear impact may be required allow sound waves to stimulate the auditory nerve. Taste and smell are lesser known for their dysfunctions, but we discussed how they(and sight and hearing) work as well. For this part of our learning, we

Neurons, probably the most important part of the nervous system, followed senses, and we learned that the 3 functions of the nervous system are sensation, integration(processing of sensory input), and motor function. The nervous system is divided into the central and peripheral nervous systems, the latter of which is divided into the sensory and motor divisions. The central nervous systems comprised of the brain and spinal cord, while the peripheral nervous system is made up of the surrounding nerves. The sensory division carries nerve impulses from the body to the brain, and the motor division carries nerve impulses from the brain to the muscles and glands. Subdivisions of the motor division are the somatic nervous system which consciously controls skeletal muscles, and the autonomic nervous system, which regulates involuntary or autonomic events. The automatic nervous system is at last divided into sympathetic and parasympathetic, which wither produces a change or the opposite that change. Neurons themselves have 5 main parts: dendrites, axons, axon terminals, the synaptic cleft, and the synapse. They are classified according to function or structure, but all of them conduct electrical signals much the same way. The nerve impulse starts off in the resting state, until something sets it off for depolarization(a switch between positive and negative charges). Depolarization occurs and propagation sends the signal across the neuron until it reaches to axon terminals to release neurotransmitter, and then the neuron is again repolarized to do its job once more.

Lastly, we covered the disorders of the CNS and PNS. Some diseases of the CNS are meningitis, an inflammation of the meninges, and epilepsy, a condition of the brain causing seizures. PNS disorders include the shingles, a reemergence of the chicken pox virus, and neuralgia, the sharp shock of pain that follow the path of a nerve. Addiction, believe it or not, is a disease as well, as it meddle with the brain's structure, pathways, and chemicals to create craving, compassion, loss of control, and continued use despite consequences in addicts.

Readings that we did this unit were "A Woman With a Hole in her Brain", "A Woman Perpetually Falling", both articles that discussed the topic in their title and relate to brain dysfunction, anatomy, and plasticity. Others included "How to Become a Superager" that explained how some elderly people could retain their younger minds through challenging themselves mentally all of the time(again, related to plasticity and evolution of the brain), "Fit Body Fit Brain" that discussed(like the previous one) how exercise can improve one's brain capacity, and "How We Get Addicted" that addressed the numerous ways that addiction can be considered a disease(relating to our nervous system disorders notes).

Definite strengths this unit included keeping up with readings and participating in class, but some weaknesses were seen in putting things off till the last minute and having a lot of work to make up. Studying for the test, too, was definitely not the best I could have done, which relates to my New Years Goals of trying to come up with better studying techniques. I did try to try new things this unit with drawing diagrams to help me study(mostly of the nervous system), but the main problem that occurred was the lack of time I had to prepare. Next time, I'll endeavor to invest more time into properly studying for the test. To end on an inquisitive note, some things that I am curious about are what parts of the brain/how much of the brain can be lost until brain plasticity is no longer able to occur, and how headaches occur.

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.