Skeletal System Flashcards
Evolution of Jaw Articulation from fishes to mammals and it’s relation to the development of the inner ear.
Fish
Reptiles/Amphibians
Mammals
Early fish have a hylostylic jaw articulation
-jaw is braced to the braincase via hyoid.
The jaw evolved into an Autostylic style in more modern fish, amphibians and reptiles.
-This means that the jaw articulation is between the Quadrate and Articular of Meckel’s cartilage (2nd pharyngeal arch of the splanchnocranium)
This free’s up the hylomandibular to form the columella ( and then the stapes)
In mammals the jaw articulation is craniostylic
Quadrate forms the incus of the middle ear
Articular becomes the malleus of the inner ear.
Which of the following is not an example of ossifications of the splanchnocraniums pharengeal arch's? A). epipterygoids B). Hyomandibular C). Quadrate D). Articular
B). Hyomandibular is not an ossification of the pharyngeal archs. It’s the structure that support the hylostylic jaw to the organism braincase.
An unidentified tetrapod has been found, upon examination of the skull its found that the baasisphenoid is fused to the epipterygoids and pterygoids but the epipterygoids are not fused or extended to the roof of the braincase by a rod-like process. This organism is most likely a:
A). Therapsid
B).Pelycosaur
C). Mammal
D). Anuran
A). Therapsid
Which is not a structure of the secondary palate?, which is important for being able to chew and breath simultaneously
A). Premaxillary
B). Maxillary
C). Prechordal
D). Palatines
D). Palatines
Identify the Endochondral component(s) amount the list: A). Cleithrum B). Coracoid C). Interclavicle D). Paracoracoid E). Scapula F). Clavicle
B, D, E
Coracoid
Paracoracoid
Scapula
Interclavicles and Clavicles are present in:
Choose all that Apply
A). Bony Fish B). Sphendon C). Primates D). Modern amphibians E). Birds
B, E
Sphendon
Birds - fused into a furculum - wishbone
Which tetrapod lacks a sternum?
A). Turtles
B). Amphibians
C). Birds
D). Mammals
Turtles lack a sternum
Along with snakes and other snake-like lizards
The paired Endochondral Pubis, Ischium and Ilium bones all articulate at the _____________________ fossa.
A). Glenoid fossa B). Acetabular Fossa C). Mandibular fossa D). Infraspinous fossa E). Supraspinous fossa
B). Acetabular fossa
“Aceta-“ = three
In all vertebrates except the crocodilians
The obturator foramen is an opening between ______ and the ________ that allows nerves to pass and is used for muscle attachment.
The \_\_\_\_\_\_ is fused to the sacral vertebrate in most vertebra, which term characterizes its arrangement to the other endochondral units? A). Dorsal B). Ventral C). Anterior D). Cranial
Pubis and Ischium
Ilium, A). Dorsal
The neural arch is composed of two sets of plates that together form the neural canal. The dorsal plate is the __________ and the lateral plates are called __________. The arch/canal is supported by the centrum.
Dorsal plate: Laminae - fuses with neural spine
Lateral plate: pediceles - fuse to centrum, forms tranverse processes
Anurans, a subgroup of the tetrapod Phylum, Amphibia, have a single caudal vertebrae that is modified for Salvatore conduction, known as the:
A). Pygostyle B). Urostyle C). Uncinate D). Synsacrum E). Zygapophyses
Urostyle - anurans single caudal vertebrae
Pygostyle - a birds fused caudal vertebrae
Unicinate - rib processes of birds that overlap the caudal rib which stablizes the rib cage for flight.
Synsacrum - fused posterior thoracic, lumbar, sacral and proximal vertebrae in birds.
Zygopophyses - are processes where vertebrae articulate which eachother
Intercentra derived centrum can be found in all these groups EXCEPT:
A). Primitive Repltiles B). Amphibia - Necturus C). Modern Reptiles D). Sphenodon E). Crossoptergyians
Modern Reptiles and Mammals completely lack Intercentrum
Except Sphenodon which is a modern reptile that still has intercentrum
Intercentrum can still be found in the tails of some primitive reptiles
Crossoptergyians, a subphyla of sarcopytergians (which is an Osteichthyes) have large intercentrum.
Somites break into three different components: myotome, dermatome and the sclerotome. The sclerotome further breaks into anterior and posterior portions. What is the purpose of this?
The posterior portion of one somite joins to the anterior portion of the adjacent somite.
The Gap created between the anterior and posterior portion of a single somite allows nerves to grow out from the neural tube and innervate the epaxial muscle derived from the myotome.
Mammalian centrum are generally acoelus except in Ungulates, who’s centrum shape is:
A). Opisthocoelous
B). Procoelous
C). Amphicoelous
D). none of the above
A). Opisthocoelous
Amphi and Pro are found in reptiles
Pro is the shape most reptiles have
The Atlas, Cervical vert 1, is associated with two occipital condyles and the odontoid process, which is also known as the:
Dens
This serves as an axis for lateral rotation
