![]() The splanchnocranium consists of the gill arches and their derivatives. What happens with the original top of the box?ĭraw a stylized (rectangular) brain box and label the parts of the neurocranium. On either side, in the nostrils, is a complex of thin bones looking like swirls of flaky pastry. The front of the box is the perpendicular bone dividing the nostrils. W hat group of bones forms the bottom and sides of the box? What group of bones forms the back of the box? W hat group of bones has holes for the cranial nerves? What group of bones surrounds the opening for the spinal cord (foramen magnum)? The neurocranium bones are painted black on the demonstration wolf and cat skulls. They cannot be distinguished from dermal bone, since they differ only in embryonic origin. Note that these bones are endochondral (or replacement or nondermal) bones. Identify the bones of the neurocranium in the wolf skull provided, using the lab drawings, and table, and the painted skulls on demonstration. The cranial nerves punch through the sides of the box. The bones forming these regions are grouped as the occipitals, sphenoids and e thmoids. If we think of the entire skull as rectangular box, the bottom, back and sides of the box make up the neurocranium. The neurocranium is a specialized portion of the splanchnocranium and comes from neural crest cells and mesodermal mesenchyme. In the Elasmobranchs (sharks and rays) it is composed of cartilage (chondrocranium), but in most other vertebrates, the cartilage is replaced by bone ( endochondral or replacement bone). The neurocranium is the portion of the skull that protects the brain and certain sense organs. 1)For the three parts of the skull, be familiar with the following:ģ) Learn the different skull types based on temporal fossaeĤ) Understand the evolution of the secondary palateĥ) Learn how the splanchnocranium contributes to jaw suspension and evolution of the middle ear in vertebratesĪs discussed in lectures there are three elements that contribute to skull formation in the vertebrates:
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |