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Learn how to perform a successful brain dissection step-by-step. Study each structure, label diagrams, and discuss details with your partner. Take pictures and develop cues for the test.
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How to perform a successful brain dissection • Perform each step of the lab, referring to this power point for guidance. • Carefully study each structure and think about what it does. • Discuss the details of each structure with your partner and develop cues that will help you during the test. • Label each structure on the brain diagrams. • Take a picture of each word underlined in the lab making note of it’s name.
STEP 1 • Use a scissors to cut away the covering around the brain known as the dura mater. • Be careful on the anterior side of the brain. Nerves (white, cord-like structures) should remain attached to the brain. • A skilled dissector can remove it in one piece. • Answer questions 1-5.
Use a forceps to gently pull on the surface of the brain. You may be able to grab hold of the arachnoid mater. Answer question 6.
STEP 2 • Find the cerebrum, cerebellum and brain stem. • What is the function of each structure? • How can you remember each structure for the test? Label diagram 7-9 and answer questions 10-12. cerebrum cerebellum Brain stem
Study the shape, size and texture of the total structure. • Compare the photos of a human brain to your sheep brain. • Complete the Venn diagram (13-15).
STEP 3 • Notice the ridges and grooves in the cerebrum. • What scientific names are given to these structures? • What is their purpose? • Answer questions 16-18.
Find the longitudinal fissure on the dorsal side of the brain? • What is a fissure? • Complete 19-21.
STEP 4 • Observe the ventral side of the brain and begin at the anterior end. You will see some of the major nerves associated with your senses. • Find the olfactory bulbs . • Use your text to find out the sense associated with the olfactory bulbs. • What is a tract? (See page 232 in your text) • Answer questions 22-24.
Observe the optic nerves. • What sense are these nerves associated with? • The optic nerves cross as the optic chiasma. • Use the internet to find out the importance of the crossing of optic fibers. • Answer questions 25-28. Optic nerve Oculomotor nerve
Observe some of the other anterior structures. You will need to find the function of the mammillary body on the internet. • Answer questions 29-32. -mammillary body -the pons
STEP 5 • Now make a midsagittal cut through the brain.
Find and label the corpus callosum. What is its function? • Label the corpus callosum (33) and answer question 34.
Find the ventricles: This is a picture of the lateral ventricle. • What is the function of a ventricle? • Label the lateral ventricle (35) and answer questions 36-37.
The 4th ventricle is connected to the 3rd ventricle by the cerebral aqueduct. • How do you think the cerebral aqueduct got its name? • Label the 4th ventricle (38) and answer question 39. 4th ventricle Cerebral aqueduct
Find the thalamus and label it on your diagram (40). • Describe its position in the brain. • Answer question 41.
Find the structures of the brain stem: label the medulla oblongata, pons andmidbrain and label them on your diagram (42-44). Spinal cord
STEP 6 Make a coronal (frontal) section perpendicular to the longitudinal fissure.
Find the gray matter and white matter. • The gray matter (also called the cortex) gets its colors from what neuron structure? • How does the white matter get its color? • Answer questions 45-47.
Can you figure out the name of these openings? Answer question 48.
STEP 7 Explore!!!!! Myelinated axons
Nick and Colton’s brain was attached to the nasal bone. Note how the nasal cavities fit over the olfactory bulbs in real life. Nasal cavities Olfactory bulbs
STEP 8 • Save your brain parts in a plastic bag just in case you need them tomorrow. • Place the bag in the tray of your cabinet. • Wash and dry your dissection tray and tools.