Post-Cranial Skeleton ï‚· Axial skeleton = vertebrae, sternum, & ribs;...
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Post-Cranial Skeleton Axial skeleton = vertebrae, sternum, & ribs; endochondral bone. Appendicular Skeleton Pectoral skeleton supports pectoral appendages (arms); dermal and endochondral bone. Pelvic skeleton supports pelvic appendages (legs); endochondral bone. Slide 2 Human Vertebra body (centrum) spinous process (neural spine) superior articular process inferior articular process transverse process neural arch facet for head of rib facet for tubercle of rib Slide 3 Intervertebral discs between (annulus and nucleus) Cervical Vertebrae 7; #1 = atlas, #2 = axis; forked neural spine on #2-#7 Thoracic Vertebrae 12 (ribs articulate) Lumbar Vertebrae 5 (no ribs) Sacral Vertebrae 5; fusion begins at 16-18 and usually completed at 25 Coccygeal Vertebrae 3-5; may become fused (= caudal vertebrae) Human Vertebrae Slide 4 Slide 5 Intervertebral Disc Problems Slide 6 Atlas, Axis, & Other Cervical Vertebrae transverse foramen (vertebral artery) Slide 7 Thoracic Vert. Articulate w/ Ribs costal cartilage Slide 8 Ribs 12; on thoracic vertebrae True Ribs 7; contact sternum directly False Ribs 5; dont contact sternum directly False / Vertebrochondral Ribs 3; fuse to a single costal cartilage element Floating Ribs 2; dont contact sternum Sternum segments fuse to form 3 bones; manubrium, body, xiphoid process (x.p. doesnt articulate with ribs) Human Ribs & Sternum Slide 9 Human Ribs Slide 10 Human Sacral/Coccygeal Vert. sacrum coccyx Slide 11 Vertebral Development Sclerotome = forms vertebral elements Myotome = forms muscle Both separated into segments when the somites form. Vertical myosepta exist between segments of myotome (derived from the somite). The myotome is also divided by a horizontal septum. Neural & hemal arches are centered on the vertical myosepta. Slide 12 Vertebral Development Slide 13 Vertebrate Neurula (section) notochord somite inter- mediate meso- derm lateral plate mesoderm gut Slide 14 Vertebrate Embryo (section) neural crest cells dermatome sclerotome myotome splanchnic mesoderm somatic mesoderm gut inter- mediate meso- derm lateral plate mesoderm Slide 15 Vertebrate Embryo (section) gut inter- mediate meso- derm lateral plate mesoderm neural crest cells dermatome sclerotome myotome splanchnic mesoderm somatic mesoderm Slide 16 Vertebrate Embryo (section) gut coelom pigment cell precursors (neural crest) ganglionic neuron precursors (neural crest) dermatome sclerotome myotome dorsal & ventral mesenteries (splanchnic mesoderm) lateral plate mesoderm Slide 17 Vertebrate Embryo (section) gut dermatome vertebra myotome horizontal septum dorsal & ventral mesenteries (splanchnic mesoderm) coelom lateral plate mesoderm Slide 18 Vertebrate Embryo (section) gut dermatome vertebra myotome horizontal septum dorsal mesentery (splanchnic mesoderm) coelom lateral plate mesoderm Slide 19 Fish Section Slide 20 Comparative Vertebra Structure Hagfishes lack vertebral structures. Neural arches dorsal to notochord surrounds dorsal nerve cord. Neural spines project above neural arch Hemal arches ventral to notochord around blood vessels in tail Hemal spines project below hemal arch notochord Slide 21 Vertebral Centra Centrum = solid bone or cartilage vertebral segment; replaces part of notochord Intervertebral pads = separate centra; derived, in part, from the notochord Centra evolved at least three times in vertebrates (Chondrichthys, Tetrapoda, & Amia + Teleosts) Slide 22 Non-tetrapod vertebrates Trunk (Thoracic, Abdominal) vertebrae = anterior; often bear ribs, lack hemal arches Caudal vertebrae = posterior; rarely bear ribs, have hemal arches Tetrapods Have Ant. & Post. Articulatory Processes Cervical vertebrae = neck vertebrae Thoracic vertebrae = have ribs (Lumbar vertebrae = lack ribs) Sacral vertebrae = attached to pelvic girdle Vertebral Regionalization Slide 23 Slide 24 Synsacral vertebrae = vertebrae attached to pelvic girdle (homologs of sacral, lumbar, some thoracic and some caudal vertebrae) Bird Vertebral Regionalization Slide 25 Atlas = first cervical vertebra in tetrapods; reduced centrum, large neural canal Axis = second cervical vertebra in amniotes (Lissamphibians have only 1 cervical vertebra, an atlas.); odontoid process (dens) for rotation of atlas, large neural canal Atlas/Occipital Condyle joint = tilting Atlas/Axis joint = rotation Cervical: Atlas & Axis Slide 26 Vertebral Regionalization GroupTrunk Vertebrae fish: hagfishes, lampreys, chondrichthyans, lungfish, actinopterygiians, many trunk (number greatly variable) amphibians 1 cervical, few to many trunk, 1 sacral mammals 7 cervical, 13-27 trunk (9-20 thoracic & 4-7 lumbar), 3-5 sacral, turtles, lizards & snakes, & crocodilians 7-9 cervical, few to many trunk (especially many in snakes), 2 sacral (0 in snakes) birds 11-25 cervical, 3-10 trunk, 10-22 synsacral Caudal (Tail) Vertebrae vary greatly in number, even within groups. Slide 27 Subphylum Vertebrata hagfishes lampreys Chondrichthys Actinopterygii coelacanths lungfishes amphibians Mammalia Reptilia centra R S G AT centra axis, >1 sacral vertebrae (Amniota) centra; atlas; sacral vertebrae; articulatory processes Slide 28 Ribs Form within myosepta from cartilage. Dorsal ribs form where the myoseptum intersects the horizontal septum Ventral ribs form where the myoseptum intersects the coelom somatic mesoderm. HOMOLOGY CONTROVERSY Slide 29 Vertebrate Embryo (section) gut dermatome vertebra myotome horizontal septum dorsal mesentery (splanchnic mesoderm) coelom lateral plate mesoderm Slide 30 Ribs dorsal rib ventral rib Slide 31 Tetrapod Ribs dorsal rib? or ventral rib? capitulum tuberculum Slide 32 Sternum Sternum (midventral endochondral element) where ribs often articulate Evolved independently in most groups. Mammalian sternum composed of multiple ossified elements (stern - ebrae); manubrium = 1st; xiphisternum/xiphoid process = last Slide 33 Subphylum Vertebrata hagfishes lampreys Chondrichthys Actinopterygii coelacanths lungfishes amphibians Mammalia Reptilia Ribs (of some kind) (Gnathostomata) 2 headed dorsal ribs, ventral ribs lost (Tetrapoda) *** * segmental sternum ** solid sternum Slide 34 Slide 35 Human Pectoral Skeleton Slide 36 clavicle supra- sternal notch acromion Clavicle (collar bone) large, connects acromion process of scapula and superior sternum; dermal Scapula (shoulder blade; endochondral Acromion process contacts clavicle Coracoid process Glenoid fossa Scapular blade Scapular spine Human Pectoral Girdle Slide 37 coracoid process Human Scapula acromion coracoid process glenoid fossa coracoid process scapular blade scapular spine Slide 38 Human Arm Bones Slide 39 olecranon process of ulna styloid process of ulna lateral epicondyle of humerus Human Arm External Slide 40 Human Hand (Manus) I III II IV V pisiform Slide 41 Human Hand (Manus) Bones Slide 42 Human Hand External Slide 43 Human Pelvic Skeleton Slide 44 Innominate Bone pelvis; 3 pairs bones; connects to sacral vertebrae; endochondral Ilium fused to sacrum Ischium posterior & inferior Pubis anterior & inferior Obturator foramen btw. pubis & ischium Acetabulum femur articulates Human Pevic Girdle Slide 45 Human Pelvic Girdle ilium sacrum coccyx ischium obturator foramen acetabulum pubis Slide 46 iliac crest (iliac spine) Human Pelvis External iliac crest (iliac spine) Slide 47 Human Leg Bones Slide 48 Human Leg External patella tibial tuberosity lateral epicondyle of femur medial epicondyle of femur tibial shaft (shin) head of fibula Slide 49 Human Pes Slide 50 Human Foot (Pes) Bones Slide 51 Slide 52 Pectoral girdle =cartilaginous scapulocoracoid Pelvic girdle = cartilaginous puboischiac bar Radials = support keratinous fin rays --Only Gnathostomes Have-- Chondrichthyan Pectoral & Pelvic scapulocoracoid puboischiac bar radials Slide 53 Scapulocoracoid (or scapula & coracoid) = endochondral; articulate(s) with radials (also endochondral) Extensive, dermal pectoral girdle Posttemporal, supracleithrum, cleithrum, clavicle, and interclavicle (median & unpaired) Fin rays = dermal bony rods (support most of fin); modified lamellar bone scales Osteichthyan Pectoral Girdles Slide 54 Radials Scapulo- coracoid Osteichthyan Pectoral Girdle Lepido- trichia Cleithrum Supracleithrum Posttemporal Clavicle Interclavicle Slide 55 Actinopterygiians - loss of ventral dermal bones (Teleosts & Amia lack clavicles & interclavicles. Gars lack interclavicles, but have clavicles.) Tetrapods - loss of dorsal dermal bones (lack posttemporal, supracleithrum, & cleithrum) Humerus = single radial articulates with scapulocoracoid in sarcopterygiians. (Glenoid fossa = articulation point) In Tetrapods - Humerus Radius & Ulna Carpals Metacarpals Phalanges Osteichthyan Pectoral Girdles Slide 56 Tetrapod Pectoral Appendages Coracoid Scapula Clavicle Interclavicle Humerus Radius Ulna Carpals Metacarpals Phalanges Glenoid fossa Slide 57 Clavicles & interclavicle in turtle ventral shell. furcula = fused clavicles & interclavicle in birds. postcoracoid = endochondral ossification unique to mammals; fuses to scapula in therians (= coracoid process of scapula) Therian mammals lack interclavicle and coracoid. Amniote Pectoral Girdles Slide 58 Echidna Skeleton Slide 59 Dermal Pectoral Girdle Group inter- clavicle claviclecleithrumsupra- cleithrum post- temporal reedfishes and sturgeons present garsabsentpresent teleosts & Amiaabsent present lungfishespresent absent amphibianspresent absent monotremespresent absent Theriaabsentpresentabsent turtles, birds, & lizards/snakes present absent crocodilianspresentabsent Slide 60 Endochondral Pectoral Girdle Group scapulacoracoid postcoracoid Chondrichthys present, fused to present, fused to absent reedfishespresent absent sturgeons