* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Sheep Brain Dissection
Single-unit recording wikipedia , lookup
Intracranial pressure wikipedia , lookup
Biochemistry of Alzheimer's disease wikipedia , lookup
Emotional lateralization wikipedia , lookup
Activity-dependent plasticity wikipedia , lookup
Neuroregeneration wikipedia , lookup
Artificial general intelligence wikipedia , lookup
Neuroeconomics wikipedia , lookup
Neuroesthetics wikipedia , lookup
Limbic system wikipedia , lookup
Neurogenomics wikipedia , lookup
Functional magnetic resonance imaging wikipedia , lookup
Embodied cognitive science wikipedia , lookup
Human multitasking wikipedia , lookup
Causes of transsexuality wikipedia , lookup
Time perception wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Nervous system network models wikipedia , lookup
Donald O. Hebb wikipedia , lookup
Neural engineering wikipedia , lookup
Cortical cooling wikipedia , lookup
Blood–brain barrier wikipedia , lookup
Neuroscience and intelligence wikipedia , lookup
Lateralization of brain function wikipedia , lookup
Neuroinformatics wikipedia , lookup
Neurophilosophy wikipedia , lookup
Dual consciousness wikipedia , lookup
Neurolinguistics wikipedia , lookup
Haemodynamic response wikipedia , lookup
Neurotechnology wikipedia , lookup
Selfish brain theory wikipedia , lookup
Human brain wikipedia , lookup
Sports-related traumatic brain injury wikipedia , lookup
Neuroplasticity wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Cognitive neuroscience wikipedia , lookup
Aging brain wikipedia , lookup
Circumventricular organs wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Metastability in the brain wikipedia , lookup
History of neuroimaging wikipedia , lookup
Brain Rules wikipedia , lookup
Brain morphometry wikipedia , lookup
Sheep Brain Dissection Sheep brains, although much smaller than human brains, have similar features and can be a valuable addition to anatomy studies. See for yourself what the cerebrum, cerebellum, spinal cord, gray and white matter, and other parts of the brain look like! Observation: External Anatomy 1. You'll need a preserved sheep brain for the dissection. Set the brain down so the flatter side, with the white spinal cord at one end, rests on the dissection pan. Notice that the brain has two halves, or hemispheres. Can you tell the difference between the cerebrum and the cerebellum? Do the ridges (called gyri) and grooves (sulci) in the tissue look different? How does the surface feel? Dorsal view 2. Turn the brain over. You'll probably be able to identify the medulla, pons, midbrain, optic chiasm, and olfactory bulbs. Find the olfactory bulb on 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 nubbly ends where they were. The nerves to your mouth and lower Ventral view body are attached to the medulla; the nerves to your eyes are connected to the optic chiasm. Using a magnifying glass, see if you can find some of the nerve stubs. The occipital lobe receives and interprets visual sensory messages. The temporal lobe is involved in hearing and smell. You can find this by looking on the outside of one of the hemispheres. You will see a horizontal groove called the lateral fissure. The temporal lobe is the section of the cerebrum below this line. The frontal lobe also plays a part in smell, plus dealing with motor function. The parietal lobe handles all the sensory info except for vision, hearing, and smell. 3. Draw the brain from each of these angles and label the structures identified in 1.& 2. above. Dissection: Internal Anatomy Half of the groups will make sagittal sections, while the other half will make cross sections through different regions of the brain. After drawing and labeling, switch with a group that performed the other section. Sagittal Section: 1. Place the brain with the curved top side of the cerebrum facing up. Use a scalpel (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. 2. Use the labeled picture to identify the corpus callosum, medulla, pons, midbrain, and pituitary gland. 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? The corpus callosum is a bundle of white fibers that connects the two Sagittal section (right hemisphere) hemispheres of the brain, providing coordination between the two. The medulla 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 the vital functions like heartbeat and respiration (breathing). The pons is 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. The pituitary gland, which produces important hormones, is a sac-like area between the pons and the optic chiasm. This might be harder to locate, especially if it has been punctured. 3. Look closely at the inside of the cerebellum. You should see a branching "tree" of lighter tissue surrounded by darker tissue. The branches are white matter, which is made up of nerve axons. The darker tissue is gray 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. Draw the sagittal view and label all the structures in bold above, as well as those below:: Ventricles contain cerebrospinal fluid. The thalamus is a "relay station" for sensory information. It receives messages from the nerve axons and then transmits them to the appropriate parts of the brain. The pineal gland produces important hormones such as melatonin, which regulates sleep-wake cycles. Descartes, the same fellow that gave us Cartesian Coordinates and “I think, therefore I am,” suggested that the pineal gland was the seat of human consciousness (he was mistaken). Cross Section 1. You can use your knife to cut cross sections of the brain (see next page). Beginning near the front of the brain (in a region called the “prefrontal lobe”), make a series of sections, each about one inch thick. In this way you will be able to see how the internal structure of the brain changes, as well as seeing how different regions and structures interconnect from front to back. 2. The darker tissue is the grey matter, which contains the cell bodies of the neurons. Histological sections reveal several distinct layers of tissue with different predominant cell types and very specific interconnections to other brain regions. The grey matter is also called the cortex, or outer layer of tissue. The lighter tissue is the white matter, which contains the myelinated long axons which interconnect distant regions of the brain. The various holes are ventricles, which would contain cerebrospinal fluid. 3. Draw those sections containing the structures listed in bold. Label your drawings. Histology Use a microscope to view a slide of motor neurons (or some other brain tissue). 1. Locate a single neuron and draw it under high power Label the following structures: cell body (or soma), dendrites, axon. Try to identify one or more synapses, the junctions between nerve cells. These might be difficult to identify. Form & Function 1. Describe the primary functions of the 3 main brain regions: cerebrum, cerebellum & diencephalon (midbrain, medulla, thalamus, hypothalamus, hippocampus, etc.). 2. How do grey and white matter differ histologically (i.e. microscopically)? Why is white matter white? How do they differ functionally? 3. Briefly describe the functions of the parts of the neuron – cell body, dendrites, axon & synapse. © 2005 Home Training Tools, Ltd. All Rights Reserved. Terms of Use. Powered by E-business Coach's ecommerce software. Brain Cross Sections Gray Matter 2. White Matter 3. Corpus Callosum 4. Lateral Ventricle 1. 5. 6. Caudate Nucleus Septum Pellucidum 7. Fornix 8. Optic Chiasm 9. Third Ventricle 10. Thalamus 11. Corona Radiata 12. 13. Hippocampus 14. Pituitary Gland Pineal Gland 15. Cerebral Aqueduct http://www.bio.psu.edu/people/faculty/strauss/anatomy/nerv/braincross2.htm