Your CRAZY Brain Option a.2 SL/HL Biology

Skill: Identifying the parts of the brain in a photograph, diagram, or scan of the brain.

The Medulla

The role of the Medulla “Swallowing center”: coordinates the muscles of the mouth, pharynx (throat), and larynx (Adam’s apple) Allows for food to move down the esophagus to your stomach vs down your trachea (windpipe) Controls breathing Monitors levels of CO2 in the blood If there is an increase in CO2 (aka low O2), the rate and depth of breathing will increase Cardiovascular center Causes heart rate to slow down or speed up

The Cerebral Cortex Cerebrum develops from front part of neural tube *Largest part of mature brain* Two hemispheres (left and right) covered by thin layer of grey matter (cells with no myelin sheath around them) called the CEREBRAL CORTEX Less than 5mm thick; contains 75% of body’s neurons!!

More intelligent animals have more developed cortical surfaces! The Cerebral Cortex Responsible for: Reasoning Language Complex thought Visual processes Motor movement Memory Speech More intelligent animals have more developed cortical surfaces!

The Cerebral Cortex Greater cognitive ability is correlated with a larger cerebral cortex Greatest difference between humans and other animals: surface area of cerebral cortex This is a result of folds (wrinkles!) // larger surface area fits into a limited amount of space

Brain vs. Body Size E:S ratio EQ Quotients Ratio of brain to body weight E= brain weight, S= body weight Larger animals = smaller brain to body ratio (small mice have a large brain vs large elephants have a relatively small brain) EQ Quotients Formula using brain weight (E), body weight (S), a Constant (C), and an exponential constant (R) E=Csr For example: if the EQ of a species is 3.0, then the Species has a value of C three times as high as a mammal of comparable weight with an average encephalization (ratio of actual brain size vs predicted brain mass)

Brain vs. Body Size

Key Parts of Cerebral Cortex Broca’s Area Speech and language Speech center** Nucleus accumbens Reward center** Responds to dopamine (promotes desire) and serotonin (inhibits desire) Drugs can also increase dopamine production, resulting in a trigger of nucleus accumbens and cause addiction Visual cortex Receives info from the retina of the eye Produces vision

Left Hemisphere vs Right Hemisphere https://www.youtube.com/watch?v=UYWBLX7aexI Two hemispheres are connected by a thick band of tissue called the CORPUS CALLOSUM Left Brain Right Brain Receives sensory input from right side of body Receives sensory input from the left side Controls muscle contraction (voluntary movement) in the left side Controls muscle contraction (voluntary movement) in the right side Controls the LEFT SIDE of visual field in both eyes Controls the RIGHT SIDE of visual field in both eyes

Computer Time! Google left brain/right brain activities (online tests) Complete AT LEAST TWO (2-3) Record your results (left or right??) on the same paper as your challenge questions Do you agree or disagree with your results? We will compare in 15 minutes

Brain metabolism and ENERGY Neurons have high energy need Brain cells need twice as much energy as any other cells in the body Glucose is primary energy source BUT neurons cannot store glucose, so blood must deliver a constant supply Blood glucose comes from the food you eat High quality carbs (fruits, veggies, legumes, grains, dairy) are best sources

Last thing! Answer these on the same page as the challenge questions and turn in when completed