ZOO 2090 Lecture Notes - Lecture 6: Haemal Arch, Notochord, Group For The Study Of Reactive Motion

• School: University of Guelph
• Department: Zoology
• Course: ZOO 2090
• Professor: Fred Laberge

Document Summary

Functions of skeleton supports weight and protects soft parts anchors muscles for movement stores minerals, particularly calcium. Main components skull (cranium) axial skeleton (vertebral column, ribs, and sternum) appendicular skeleton (girdles, fins, and limbs) Head skeleton three components of the skull: chondrocranium (neurocranium, splanchnocranium (visceral cranium, dermatocranium (covering other 2) Splanchnocranium (visceral cranium: most ancient supports pharyngeal slits in the protochordates, gills and respiratory muscles in vertebrates some elements contribute to the jaws and hyoid apparatus in gnathostomes (first two pairs) Agnathan skull anaspid without armour pteraspidomorph with dermal bone armour. Placoderm skull: bothriolepis left --> view without dermatocranium. Jaw suspension: early fishes: euautostylic, upper jaw braced against braincase, hyomandibular not involved (primitive, lungfish, amphistylic, upper jaw supported by hyomandibula and connection with braincase (some cartilaginous and bony fishes) arch not involved. Hyoid: contact with chondrocranium (otic capsule) principally through hyomandibula; palatoquadrate can slide forward, increasing gape, autosyly, quadrate attaches chondrocranium and jaw directly, with no support fro m hyomandibula.