Brain+Dissection+Procedure

//**Brain Dissection Procedure**// //**Overview**// General set of instructions for dissecting mammal brains. There will be differences in the sizes of the structure and brain regions in each type of brain. The structure nd relative location will be the same or very similar.

Follow safe laboratory practices when performing any dissection. Wear goggles,gloves,and lab coat while dissecting. When performing dissection use a dissecting tray to contain specimens and fluids. Be reminded to always use precautions
 * //Safety//**

//**Procedure**// 1. Review the glossary of the dissection guide and refer to the Mammal Brain Section diagram to help observe and identify external and internal structures.

2. Place the brian dorsal side up on the tray

3. If the dura mater wasnt removed observe them. Use forceps to gently remove the layers of pia and arachnoid which covers the adheres to the surface of the cerebrum.

4. Analyze the cerebrum. Observe the grooves and ridges known as sulci and gyri. Analyze the medical longitudinal fissure, The longitudinal fissure separates the right and left hemisperes of the cerebral cortex.

5. Locate the four lobes of the cerebrum. In the frontal lobe it controls the motor functions. In the back is the parietal lobe, which recieve and process somatic sensory information. Next are the temporal lobe and this receive and process auditory sensations. The back of the cerebrum makes the occipital lobe, which recieves and precesses sensation fro the eyes.

6. Take a look back at your vocabulary words and locate the word cerebellum. This is what you need to locate next. It is divided by a dorsal ridge called vermis.

7. Now its time to place the brain on the dissecting tray. Place the brain ventrak side up and find the following: medulla, pons, brain stem, and spinal cord.

8. The olfactory bulb which is located below the frontal lobe of the cerebrum should be able to be indentified. The optic nerve has been removed but there are still portions of the optic chiasma

9. Now place the brain with the back side up. Gently widen the medial longitudinal fissure with your fingers. Insert the scapel and cut through the corpus callosum which connect the two cercbral hemispheres. By doing this it should divide the cerebrum, cerebellum, and brain stem into two longitudinal halves.

10. Each hemisphere have a lateral ventricle that is referred to as the first and second ventricles. This can be found by removing the spetum pellucidum. The spetum pellucidum is thin and transparent membrane located lower to the corpus callosum on each hemisphere.

11. Find the third and fourth ventricles. The fourth one connects to the central canal of the spinal cord. Thsi is also connects to the third ventricle by a cerebral aqueduct. Look over each ventricle and try to identify the choriod plexus. Tis produces cerebrospinal.

12. The cut side facing up, locate the thalamus, hypothalamus, pineal body, pons, and medulla.

13. Observe the cut surface. In the middle section, the white matter forms a branched, treelike pattern called the arbor vitae. Also see can you identify this pattern.

14. Find the midbrain region, locate between the thalamus and pons. This contains important nerve tracts. The corsal of the midbrain are concerned responses to visual and auditory stimuli.

15. Through the cerebral hemisphere make a cross section through it. Indentify the ineer white matter and outer gray matter.

16. Next, you take out the cerebellum and the remainder of the cerebral hemisphere by dissecting away everything dorsal to the floor of the lateral ventricle. This will show the hippocampus which is involved with emotions and memory.

17. Locate the rest of the thalamus after removing the hippocampus

18. You will need to dispose the specimen in accordance with local guidelines and teach instructions.