Splanchnocranium - embryology - somitomeres NOT hypomere. (branchnimeric- RED)
Regions -
Appendicualr - embryology: somites (pectoral- PINK (raise and lower fins) and pelvic)
Visceral - Embryology: hypomere, smooth muscle of organs and blood vessels (eretors (erectopillie), of hair and feathers in cardiac muscle)
Epibranchial (preotic myotomes become extrisic eye muscles)
Epibranchial (preotic myotomes become extrisic eye muscles)
Cranial nerve III (tract of the brain) dorsal, ventral, medial rectus and ventral oblique
Cranial nevre IV dorsal oblique
Cranial nerve VI lateral rectus
SLIDE 32
Hypobranchial
originate from post cranial somites
evideced by spinal cord innervation
opening lower jaw in fishes
throat, hyoid, larynx & tongue in tetrapods, ex (genioglossus - protraction, styloglossus- retraction - from spinal cord under brain)
Branchiomeric
from somitomeres and somites, NOT splanchnic mesoderm
primitively for buccal pump
cranial and spinal innervation
XI is entrapped in the cranium of amniotes
Branchiomeric
Mandibular arch
cranial Nevre V - #5
adductor mandibulae & levator palatoquadrate(tetrapods loose this) in fish
Masseter(bc we are chewers), temporalis (closer) and pterygoideus(side to side chewing) in mammals
Branchiomeric
Hyoid arch #7
Levator hyomandibula in fishes
stapedius in mammals
small interhyoidus in fishes, extensive facial muscles in mammals
in tetrapods irs now for hearing- stabilizes stapes
Branchiomeric
posterior arches
buccal pump in fishes (gill puches) (9+10) 11 for the poserirmore - not cranial nerve)
larynx + throat in tetrapods
some fuse to cucullaris
trapezius and mastoids in mammals (neck and shoulder girdle )
Epaxial/ Hypaxial
largest muscles in fish, locomotion (postcranial)
no horizontal septum in lampreys
relatively short fibres, deep zig- zagging to increase length (anterior -> posterior) more range of motion
Epaxial / Hypaxial
trend to reduce myosepta in tetrapods, form sheets
hypaxial musculature extensively modified, forming layers with fibers in alternate orientations ventaltion and trunk mobility (side to side/ up and down)
Electrogenic Organs
modified muscles in aquatic vertebrates
disc shaped cells, electroplaques
generates a 0.15V potential from action potential
may be combined in series for voltage or in parallel for current
Electrogenic Organs
independently evolved (convergent evolution) from axial, branchiomeric and even musculature
strongly electric fish stun prey and or repel predators
weakly electric fish sense environment live in murky waters
communication as well - use electric currents to conduct currents and sense objects