Sheep brains, like othersheep organs,are much smaller than human brains but have similar features. They can be a valuable addition to your study of anatomy.
See for yourself what the cerebrum, cerebellum, spinal cord, gray and white matter, and other parts of the brain look like with this sheep brain dissection guide! Use this for a high school lab, or just look at the labeled images to get an idea of what the brain looks like.
Download:Sheep Brain Dissection Lab
Observation: External Anatomy of Sheep Brain
1. You’ll need apreserved sheep brainfor the dissection. Set the brain down so the flatter side, with the whitespinal cordat one end, rests on thedissection pan. Notice that the brain has two halves orhemispheres. Can you tell the difference between thecerebrumand thecerebellum? Do the ridges (calledgyri) and grooves (sulci) in the tissue look different? How does the surface feel?
2. Turn the brain over. You’ll probably be able to identify the medulla, pons, midbrain, optic chiasm, and olfactory bulbs. Find theolfactory bulbon each hemisphere. These will be slightly smoother and a different shade than the tissue around them. The olfactory bulbs control the sense of smell. The nerves to the nose are no longer connected, but you can see nubby ends where they were. The nerves to your mouth and lower body are attached to the髓质; the nerves to your eyes are connected to theoptic chiasm. Using a magnifying glass, see if you can find some of the nerve stubs.
Sheep Brain Dissection: Internal Anatomy
- Place the brain with the curved top side of the cerebrum facing up. Use ascalpel(or sharp, thin knife) to slice through the brain along the center line, starting at the cerebrum and going down through the cerebellum, spinal cord, medulla, and pons. Separate the two halves of the brain and lay them with the inside facing up.
- Use the labeled picture to identify the corpus callosum, medulla, pons, midbrain,t和脑下垂体高度的地方o the brain. (In many preserved specimens the pituitary gland is no longer present. It is not pictured.) Use your fingers or a teasing needle to gently probe the parts and see how they are connected to each other. What does that opening inside the corpus callosum lead to? How many different kinds of tissue can you see and feel?
- Thecorpus callosumis a bundle of white fibers that connects the two hemispheres of the brain, providing coordination between the two.
- The髓质is located right under the cerebellum. In this the nerves cross over so the left hemisphere controls the right side of the body and vice versa. This area of the brain controls thevital functionslike heartbeat and respiration (breathing).
- Theponsis next to the medulla. It serves as a bridge between the medulla and the upper brainstem, and it relays messages between the cerebrum and the cerebellum.
- Thepituitary gland, which produces important hormones, is a sac-like area that attaches to the brain between the pons and the optic chiasm. This may or may not be present on your specimen.
3. Look closely at the inside of the cerebellum. You should see a branching ‘tree’ of lighter tissue surrounded by darker tissue. The branches arewhite matter, which is made up of nerve axons. The darker tissue isgray matter,which is a collection of nerve cell bodies. You can see gray and white matter in the cerebrum, too, if you cut into a portion of it.
4. You can also use the letter labels on the internal anatomy picture to try to find the following:
- Ventriclescontain cerebrospinal fluid
- Theoccipital lobereceives and interprets visual sensory messages
- Thetemporal lobe听觉和嗅觉。你可以find this by looking on the outside of one of the hemispheres. You will see a horizontal groove called thelateral fissure.The temporal lobe is the section of the cerebrum below this line.
- Thefrontal lobealso plays a part in smell, plus dealing with motor function
- Theparietal lobehandles all the sensory info except for vision, hearing, and smell.
- Thethalamusis a ‘relay station’ for sensory information. It receives messages from the nerve axons and then transmits them to the appropriate parts of the brain.
- Thepineal glandproduces important hormones.
Do some more research to find out about these structures in detail.
5. If you have amicroscope, slice off a very thin section of the cerebrum and put it on a slide, covering it with a drop of water and a coverslip. Look at it under 100X and 400X magnification. Follow the same procedure with a section of the cerebellum, then compare and contrast the two.
What other users say:
Fun and Educational. We dissected these brains as part of our co-op science class. The kids had a fun time with this hands on experience and it was great to actually be able to locate and see different sections of the brain.
