having problems asking these questions are they correct what can be added ( plac

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having problems asking these questions are they correct what can be added ( placed ? marks where I do not know)

Describe how the pectoral and pelvic girdles articulate with the skull and axial skeleton in fishes and tetrapods

Appendicular skeleton are paired fins or limbs and girdles. Anterior girdle is the shoulder or pectoral girdle. Dermal and endochondral skeletal elements support pectoral fin or limb. Posterior girdle is the hip or pelvic girdle. Endochondral skeletal elements that support the pelvic fin or limb.

Tetrapods have a loss of the pectoral girdle attachment to the skull, which allows increased cranial mobility. The pectoral girdle is structurally and functionally detached from the skull. Girdles and limbs became stronger and more completely ossified and has no attachment to vertebral muscle.. The pelvic girdle was composed of a single bone with three fused parts, the pubis, ischium and ilium. Through the ilium the pelvic girdle became attached to the vertebral column and defined the sacral region. The acetabulum articulates with head of femur. The ilium articulates with the vertebral column. The fins of fish ancestors were replaced by digits.

In ray finned fishes the largest element of the shoulder girdle is the cleithrum.The cleithrum meets the clavicle, which bends at the midline beneath the gill chamber and they join together. The cleithrum also supports a supracleithrum and in turn a posttemporal through which the dermal girdle attaches to the back of the skull. The pelvic girdle has no articulation with the vertebral column.

Explain how the limbs or fins articulate with the girdles in fishes and tetrapods?

The anterior girdle is the pectoral girdle that supports pectoral fin or limb.The posterior girdle is the pelvic girdle that supports pelvic fin or limb.There is a basal pterygiophore that articulates the fin to the pectoral girdle fish. All fins are supported by basals and radials, the basals being nearest to the girdle.  

In Chondrichthan (Squalus), u-shaped girdles extend across the midline of body. The pelvic girdle is based on a single element, the puboischiac bar, that is embedded in the musculature of the trunk   The girdle halves are fused producing the scapulocoracoid, that is joined to the other half of the pectoral girdle by the coracoid bar.

In ray finned fishes the pectoral girdle is partly endochondral but mostly dermal. The dermal pectoral (shoulder) girdle forms a U-shaped collar of bone around the border of the gill chamber and braces the scapulocoracoid. The scapulocoracoid attaches the fin to the girdle. The pelvic girdle are made of 2 small plates of bones and has no articulation with the vertebral column.

Lobe fin fishes how are fins articulate with the girdles?  

In tetrapods, the pelvic girdle has three bones, the ilium, ischium, and the pubis. The acetabulum where the femur meets with the pelvis forms the "hip joint" which connects the limbs with the pelvic girdle in tetrapod. Tetrapods have a shoulder girdle consisting of dermal and endoskeletal elements. Unlike their first ancestors, early tetrapods have a shoulder girdle that is detached from the skull, The pectoral (shoulder) girdle is made of the paired cleithrum and clavicle, and an unpaired interclavicle that joins both halves of the girdle across the midline. Later tetrapods have a three part shoulder ? Scapulocoracoid element ?

Lobe finned fishes the dermal pectoral (shoulder) girdle includes a cleithrum and clavicle. The girdle includes a scapulocoracoid that supports the fin elements. Paired pelvic fins rest on a single cartilaginous girdle element. The paired girdle do not meet at the midline and they do not articulate with the axial column. They are embedded within the body wall offering a bone base which the fin project outward from the sides of the fish.

Explanation / Answer

like mammals fishes and tetrapods have 2 types of girdles in the body. the pectoral girdle and the pelvic girdle. the pectoral girdle is placeace towards the ranial part behind the cervical vertibraes and from here appendeces (fore limbs) and skull of the body attaches. the pectoral girdle is formed bu scapula, clavicle and coracoid.the roof is formed by the thoracic vertibrae. sidewalls are formed by ribs and floor formed by sternum. it attaches to the skull towards its cranial aspect and the forelimb is attached to the glenoid cavity of scapula. whereas the pelvic girdle is located to the caudal part of the body. it is made bu fusin of 3 bones i.e. ilium ischium and pubis. the roof is formed by sacrum side walls by ilium and ischium and floor by pubis. the hind limbs are attached with the pelvic girdle by acetabulum cavity.

2. the fin is articulated to the body by the help of scapulacoracoid element which is a ventral part of clavicle. the inside surface of supracoracoid element bears a cavity from where the fin is attached.

3. in case of tetrapods the two clavicles and inter clavical bones are grown ventrally to form a broad chest plate. The upper part of girdle bears a flat scapular blade along with glenoid cavity located below which acts as articulation area for humerus (fin), the ventral surface was large and bears a flat coracoid plate

4. the supracoracoid element is the element from where the head of humerus is attaches as the fin as it forms a cavity called as the glenoid cavity which helps in articulation of the head of humerus

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