The Human Brain: Form and Function
The brain is what makes each of us different human beings. It controls everything we do from breathing to playing an instrument or catching a ball. Not only that, but the brain controls everything that we feel and how we think. Our brain gives us the ability to make choices in our lives, it makes decisions, plans and imagines. The brain is what makes humans different from other animals. When an infant is born their brain weighs about 400 grams and grows to be about 1400 grams. The adult human brain consists of three main parts: the cerebrum, cerebellum and the brain stem. The cerebrum is the largest part of the brain that controls and integrates thinking, memory and five senses. It is divided into two hemispheres, the right and the left. The left hemisphere directs the right side of the body while the right hemisphere guides the left side of the body. This is due to the axons that cross over to the opposite side of the body in the spinal cord.
Although most brain activity involves both hemispheres, the left side primarily governs logical, objective and analytical thinking such as speaking, reading, writing and problem solving. The right hemisphere controls the abstract, intuitive and subjective part of us, such as imagination, appreciation and creativity. These two halves however are connected by a band of nerve fibers, the corpus callosum that allows the two halves to communicate (Freidman, 1990).
The cortex is the outer layer of the cerebrum that collects information via our five senses. It is made up of four sections called lobes: frontal (reasoning, planning, parts of speech, movement, emotions and problem solving), parietal (somatosensory functions), temporal (hearing and memory) and occipital (vision).The cerebellum is located at the lower back part of the cerebrum and controls movement, balance and posture. The brain stem connects the cerebrum, the cerebellum and the spinal cord. It controls breathing, heart rate, digestion and blood pressure. At the top part of our brain stem lies the pleasure center (Freidman, 1990). Things like food, drink and sleep make us feel good by activating the pleasure center. Near the pleasure center at the top of the brain stem is the hypothalamus. It regulates body temperature, appetite and sleep patterns (Freidman, 1990).
In addition, the hippocampus and amygdala are vital in the anatomy of the brain. These regions are affected directly by many stimulants. The hippocampus plays a major role in long term memory and spatial navigation. It is also involved in the formation of new memories. The amygdala are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain. The amygdala performs a primary role in the processing and memory of emotional reactions (Freidman, 1990).
Lesson 1 - Geography of the Brain
Objectives: Students will learn the three main parts of the brain: the cerebrum, cerebellum and the brain stem. Students will recognize that the brain has two hemispheres, each which control different moods and cognitive function.
Materials: Oatmeal, Cardstock, Zippered bags, Model of a brain and or diagrams/ photos of the brain
Prior Preparation: Cook oatmeal as instructed and place in 4 zippered bags. Allow the bags to sit for at least 15 minutes in order to become firm. Cut a diagram of the brain into its three main parts and paste on card stock. Be sure each piece fits together like a puzzle. Be sure to have 1 set per student of these three puzzle pieces.
Procedure:
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1) Pass around the bags of oatmeal and allow students to observe and feel its contents.
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2) Have students' hypothesize what body part they think this represents and share their thoughts with the class.
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3) Tell students that they are feeling oatmeal. Have them describe what they are feeling. Tell them that oatmeal is very much like the human brain. Although we may think the brain is hard, what we are actually feeling when we touch our head is our skull. The skull is made of bones that protect the brain. The brain itself however is mushy.
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4) Administer a pre- assessment of the structure of the brain. It can be later given as a post assessment following the completion of the unit.
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5) After completing the pre-assessment, pass around a model of the brain or a few labeled diagrams of the brain. Ask students to guess how much they think the brain weighs (3 pounds).
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6) Explain that the brain is divided into many parts, but today you will learn the three main parts: the cerebrum, cerebellum and the brain stem.
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7) Display on an overhead the three main parts of the brain and pass out one envelope holding the brain puzzle to each group (4 groups).
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The students can remove the three pieces from the envelope and place on their desks. Ask them to find the largest part. This is the cerebrum. It is the largest part of the brain and contains many bumps and grooves. Explain that it contributes to your thinking, your fives senses and your memory.
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8) The students can then label the back of their puzzle piece and write the facts that they just learned about it.
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9) The cerebrum is divided into two hemispheres, the right and the left. It is divided down the middle from the top of your head to the bottom.
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10) Next have the students locate the second largest puzzle piece which is the cerebellum. It is located at the lower back of the cerebrum and controls movement, balance and posture,
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11) Have the students label and write what they have learned on the back of their puzzle piece.
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12) The students should now look at the last piece, known as the brain stem. The brain stem connects the other two parts to the spinal cord. Mention also that it controls breathing, heart rate, digestion and blood pressure.
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13) Students will now label and write what they have learned on the back of the puzzle piece.
Closure: Have students share what they learned about the brain today. On chart paper have students formulate questions about what they have learned and what they want to learn about the brain as we begin our study. Based on what they have learned about the brains' function, ask students why they think its important to keep their brain healthy and what may happen if they impose unhealthy habits on it, like, smoking, alcohol or drugs (Science Teacher Education Partnership Program, 2005).
Lesson 2- Daily Log
This lesson will allow students to better understand the role that the brain plays in their life. It will also help them to later understand that when stimulants then affect these parts of the brain, how their actions and bodily functions are altered.
Objective: Students will recognize how their daily activities are controlled by their brain function.
Materials: Mini journals 1 per student, Resources for Research: access to a library/ computer
Procedure: Have students complete a daily list of activities from the time they wake up until they go to bed. Students should do this for 1 week. Next, students should research what part of the brain controls the functions necessary for each activity.
Closure: Students can share what they have learned about the brain as the main control center and how it affects their daily life (Science Teacher Education Partnership Program, 2005).
(Example of a table to be completed by students.)
Lesson 3- Build A Brain
Objective: Students will better understand the structure of the brain as they create their own model.
Materials: (the following recipe will make one brain, be sure to have enough that each student can create his/her own)
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1.5 cups instant potato flakes
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2.5 cup hot water
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2 cups clean sand
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1 gallon zippered bag
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Procedure: Combine all of the ingredients in the zippered bag and mix thoroughly. It should weigh about 3 lbs. and have the consistency of a real brain
Closure: Have students share about what they learned about the brain, its weight, color, texture and size through making the model (Chudler, 2009).
Lesson 4 -Thinking Cap
Objective: The students will cover their brain with a thinking cap created from paper mache.
Materials: Newspaper, Plastic Bowl that fits the size of the students' head and Paste: White glue and water (about 2 parts glue to 1 part water), White flour, salt and water (1 to 1 consistency with a few tablespoons of salt), Liquid starch
Procedure: You will build your cap around the bowl. Cut strips of newspaper and glue them to the form using paper mache paste. Coat the newspaper strips with the paste, and place them on the bowl. Let each newspaper layer dry before you add a new layer. Add enough layers to give a strong structure. When the structure is dry, remove the underlying bowl. Finally, decorate the thinking cap by labeling the parts of the brain in their appropriate space.
Closure: Students can share their thinking caps and in doing so explain the various parts of the brain and what each part controls. Students can use their tables to discuss as well (Chudler, 2009).
In order to truly appreciate this miraculous structure we must look at how the brain can function so well under difficult conditions that we impose on it. There is a tremendous balance of both excitation and inhibition forces running through it at all times. The inhibitory chemicals suppress the activity of nerve cells while excitation receptors accelerate the firing of nerve cells. In order to understand the necessity for this delicate balance and how drugs disrupt it, it's vital to understand the building blocks of the central nervous system (Kuhn, Swartzwelder and Wilson, 1998).
