The Brain

The first month of our biobiography project, we focused on the brain. I learned that the brain works by taking sensory information from receptors, in our skin, nose, mouth, ears, and eyes, relays that information through our nervous system to the brain, and sensations are then perceived. During this part of the project, we were also able to dissect a sheep brain, and locate the different structures. We then compared the sheep brain to a human brain, and where everything was located, in order to better understand what happens in our brain and why.

Anatomy of the Brain – Dissection

The purpose of the sheep brain dissection was to understand the anatomy of a sheep brain and the similarities and differences when compared to a human brain through research. In total, we made 4 cuts, and if done properly, we could identify 64 structures in the brain. Some of the parts of the brain are; the meninges which is a protective enclosure over the brain and brainstem, then there is the cerebellum, homunculus, frontal cortex, medulla oblangata, the pituitary gland, the corpus callosum, the hippocampus, the optic chiasm, and the cerebral cortex. One important part of the brain that has to do with our decision making, emotions, problem solving and higher level of thinking, is the frontal lobe. This then helped us see why certain structures were near other parts in the brain that had a related function, such as the optic chiasm and optic nerves, both of which have to do with sight.

From dissecting a sheep’s brain, I have learned that a sheep’s brain is very similar to a human brain as many of the structures are in the same general area and pretty much do the same thing. Some of the major differences however, have to do with the size, shape, and location or position of structures in the brain. In general, the sheep brain is about a third the size of a human brain and has many physical difference which affect the way sheep think and live and how we think and live. In a sheep’s brain, the hippocampus is smaller because it doesn’t have to process emotions, like we do. A human’s hippocampus is larger because we require, and depend on, more memory and a greater ability to learn and make decisions. The cortex, or outer layer of the cerebrum is composed of sulci, the depressions or valleys, and the gyri, the ridges or mountains. A human brain has deeper sulci, and higher gyri, because we are able to obtain a higher level of thinking, that involves problem solving and decision making, which generally happens in the cerebral cortex (the outer layer of the brain).

The cerebral cortex is the outer layer
depicted in dark violet.

The cerebellum is the part of the brain in the back of the cerebrum, and it regulates balance, posture, movement, and muscle coordination. Human behavior and motor control is controlled by the cerebellum, and a sheep’s brain has a much smaller cerebellum because they don’t have to control as much as we do, like opposable thumbs,fine motor skills, and require less learning abilities than a human. In a human brain, the cerebellum resides to the back and bottom of the brain because we evolved to have a vertical spine and walk on two legs, while sheep have a brain with a cerebellum sticking out the back, because their spine is horizontal and they walk on four legs.

A sheep brain’s cerebellum resides towards the Posterial (back) side of the brain because a sheep stands, walks, and lives with a spine that is horizontal. A human’s cerebellum is more towards the Ventral (bottom) part of the brain because a human walks and talks on two legs with a vertical spine.

By dissecting the sheep brain and seeing where the parts were located, in relation to other parts, I was also able to picture where they would be located in a human’s brain, or more specifically, my brain, what their function is, and then also note the similarities and differences between a sheep brain and human brain. Once we were done with the dissection, we plasticized part of the brain and then stuck it onto our brain display, to compare our drawing or a human brain with a sheep brain. This also helped me understand how our brain takes information and uses it to perceive the world around us.

Our perception of the world requires various elements or sensations to be organized, related and grouped together. When a receptor for pain, touch, smell, taste, hearing or sight is activated, the receptors relay the information to the brain stem, and then up to various parts in the brain that can organize the information, such as the olfactory bulb for smell, or the temporal gyrus and auditory cortex for hearing. When an experience such as pain, which is activated by Nociceptors (the sensory fibers that respond to tissue damage and cause pain), the pain messages are transmitted to the spinal cord, via small myelinated fibers (which evoke sharp, fast pain), or C fibers (which are unmyelinated), and relayed to several brain structures including the thalamus and cerebral cortex (where the pain message becomes a conscious experience). The setting and emotional component also play a part in making memories. The medial temporal lobe, hippocampus, and parahippocampal region play critical roles in converting (but not permanently storing) memories of experiences from short-term (working memories) to long term, permanent memories. New experiences, cause information to enter the nervous system, which is then relayed to the parts of the brain that maintain relevant information during working memory (such as the prefrontal cortex) and then becomes permanent, declarative memory that can be recalled on or non-declarative knowledge such as muscle movement.

 

The Brain Cell – Structure and Function

Neurons are highly specialized for the processing and transmission of cellular signals. The soma is the central part of the neuron. It contains the nucleus of the cell, and therefore is where most protein synthesis occurs. The dendrites of a neuron are cellular extensions with many branches, and metaphorically this overall shape and structure is referred to as a dendritic tree. This is where the majority of input to the neuron occurs. The axon is a finer, cable-like projection which can extend tens, hundreds, or even tens of thousands of times the diameter of the soma in length. The axon carries nerve signals away from the soma. The axon terminal contains synapses, specialized structures where neurotransmitter chemicals are released in order to communicate with target neurons.

The gray matter is formed from neurons and their unmyelinated fibers, the white matter is formed predominantly by myelinated axons interconnecting neurons in different regions of the cerebral cortex with each other and neurons in other parts of the central nervous system.

Learning – Brain Physiology and Mindset

Learning is the analysis of information not just passive absorption. analyzing information and learning comes from mindset not desire. Those that embrace confusion as a good thing to learn, while those that think of confusion as a negative barrier, are passive and don’t learn as much. There are two types of mindsets, a growth mindset and a fixed mindset. People with a fixed mindset think of intelligence as a fixed trait, while people with a growth mindset think of intelligence as a malleable quality, and a potential that can be developed. When encountered with a challenge, people with a fixed mindset become frustrated, disengaged, and hopeless, while students with a growth mindset feel challenged, remain effective, and continue to try.

 

Stream of Consciousness Life Thought:

The table is dark, black like the pen in my ink, it’s kind of funny how the lines make words like apple, yumm they are red and shiny like spoons you eat soup but sometimes  hits hot like yesterday I wish I was somewhere cooler like Alaska theres snow their in the winter cold the bubbles in the fish tank Mr leader says hurry I don’t like being rushed, fast like a car, Jacob has a different car he drove this morning, the paper is rough and smooth at the same time like sand, I wonder what makes sand soft why it the beach so hot there aren’t many trees I like drawing trees, there aren’t trees underwater, trees don’t have lungs or gills fish have gills I wo.. my nose is itchy.. why is the paper have a red line and to… only one of my feet are flat on the floor. Mr leader only uses red blue and black.. pachyderm

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2 Responses so far »

  1. 1

    Julie Miller-Farmer said,

    Hello I was just wondering if you were okay with students using your images.

  2. 2

    Cherry Blue said,

    great presentation mind blowing


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