Introduction
The US Congress voted the 1990's the decade of the brain. Thanks to the advent of imaging methods, such as CT (computer tomography), PET (positron emission tomography) and MRI (magnetic resonance imaging), brain mapping flourished. Brain mapping, or the understanding of which regions of the brain are responsible for specific mental processes, has allowed us to better understand the structure-function relationship of this previously mysterious organ. This unit is appropriate for middle school science education and will cover the basic anatomy of the brain and the functions of specific regions of the brain. The mechanism of Parkinson's Disease and the impact of alcohol on the brain are discussed.
There are many divisions made to brain structure for the purpose of understanding all it's functional regions. Like a Russian matryoshka doll, a doll within a doll, the brain has various levels at which structure and function can be detailed, but the most superficial division can be made between the brain's macroanatomy and microanatomy. The macroanatomy is the larger global anatomy, divided into segments that are large enough to see with our eyes, the macro structures of the various parts of the brain. The large convoluted structure of the cerebrum is an example of the brain's macro-anatomy. The cerebrum is the brain's processing powerhouse. The cerebrum is further divided into the right and left hemispheres, with the right hemisphere serving the left side of the body and vice versa. And when we look further within each hemisphere, we find the frontal lobe, parietal lobe, occipital lobe, and temporal lobes (See Diagram 1) providing numerous functions, such as our senses, comprehension, speech and our perceptions of our body's orientation in space. As will be further illustrated, our current descriptions of the brain's structure, is largely based on isolating regions that are functionally related.
The most prominent feature of the brain's microanatomy is its cellular structure, particularly the presence of neurons. Neurons are the brain's functional cells. It is within this microanatomy that we find a network of cells communicating at amazing speeds using electrochemical means. These electrochemical pathways link different regions of the brain. Neurons from one functional region literally reach out to link it to other regions, thus bestowing us with the remarkable ability to both see and understand what is being seen at the same time, for example.
A basic understanding of brain structure and function should be incorporated into the middle school life science curriculum. The brain is largely neglected in the middle school curriculum perhaps because it seems too complex to be addressed at this grade level. But as our understanding of the brain advances, one can't help but feel this void in middle school curriculum makes it out of date.
In my experience as a 7th grade life science teacher, many students show interest in understanding the brain and ask sincere questions about brain structure and how it functions. Many of these questions seek to understand how other animals' or mammals' brains relate to humans or what is happening in the brain of family members with a neurological disorder. Questions about diseases like Parkinson's Disease and Alzheimer's Disease or the effect of drugs and alcohol on the brain often arise. Without a common technical language and a basic understanding of the brain and how it functions, I am able to answer such questions only in a superficial way.
As a public school life science teacher at Everett Middle School, I try my best to educate my students with texts, journals, videos, labs and field trips. With the learning I've obtained from the Yale Teacher Initiative Seminars and curriculum writing, I will be able to bring a deeper understanding of the brain to my students, which in my opinion must begin with the knowledge of brain structure and how those structures contribute to brain functions.
Everett Middle School serves approximately 600 students in the Castro/Mission District of San Francisco California. The student population is of a low economic class (95% receive free lunch), minority (70% Latino, 15% African American, 5% Asian, 10% Other etc.) and many perform below or far below basic reading and math skills. In addition, many have behavioral problems attributed largely to living in a culture that doesn't address their needs more directly and to being raised in families that struggle to survive. It is important that any topic I teach be presented in a fashion that makes it accessible to this student population.
Most of my lessons are presented in a fashion that encourages conversation, questioning, and exploration using plenty of visual aids and dramatization. This approach to teaching is important to keep the attention of all students learning life science, but also to accommodate the ELL student (English Language Learner), which is a constant consideration for me. I feel it's important to stress that one of my primary teaching goals is to both engage a student and to present materials in a way that makes science accessible to them. Additionally, I attempt to provide them with the opportunity to take ownership of academic knowledge without hesitation to be involved in the learning process and in a fashion that is not degrading. To accomplish these goals, I have designed a unit on brain structure and function with an approach that makes what is seen as a difficult subject more accessible to the student learner. The unit is divided into three sections, which examine the brain at different levels.
Section One of the Brain Structure and Function Unit will discuss brain gross anatomy and its relation to brain function. Several important concepts will be introduced: the subdivisions of the brain, the role of the cerebral cortex, the role of the cerebellum and the brain stem. Projects and labs will be suggested to enforce the concepts of Section One, such as a comparative look at the anatomy of brains across a few chosen species using visual aids to further enforce the knowledge of the regions of the brain.
Section Two will introduce brain microanatomy, particularly the role of neurons. The anatomy of the neuron will be presented, as well as mechanisms that neurons use to relay information to one another. The biology of neurotransmitter-receptor binding (neurotransmission) is covered.
Section Three covers Parkinson's Disease and alcohol. To synthesize the two prior sections on macroanatomy/function and microanatomy/neurotransmission, Parkinson's disease is covered. Parkinson's disease is a good model in that it involves a specific neurotransmitter (dopamine) and receptors, occurs in a specific region of the brain involved in motor function (midbrain), and has a profound effect on functioning. A discussion of alcohol will further bring together prior learning.
This unit is written in hope that all middle school teachers can implement the unit into their science and health curriculum. I also hope this unit will further foster student engagement in the study of life science and allow for its application to real life situations through knowledge and critical thinking.
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