Skeletal System LAB

Question 1

is derived from several sources. Due to this complexity, it is named according to its embryonic origin

Answer 1

skull

Question 2

is the original cartilaginous braincase, which later ossifies into cartilage bone (neurocranium).

Answer 2

chondrocranium

Question 3

dermal bones which later become attached to the surface of the chondrocranium.

Answer 3

dermatocranium

Question 4

(visceral skeleton) is composed of endoskeletal arches that support the gills but later develop as part of the braincase.

Answer 4

splanchnocranium

Question 5

large cavity within the rostrum and is continuous posteriorly with the much smaller precerebral fenestra (cranial opening).

sharks

Answer 5

precerebral cavity

Question 6

thick protuberances behind the nasal capsule and continuous with the supraorbital crest which forms the dorsal wall of the orbit.

Answer 6

antoorbital process

Question 7

triangular in shape, and continuous with the crest of the supraorbitalis. This is marked by the dorsally projecting process.

shark

Answer 7

postorbital process

Question 8

found depression immediately located medially at the level of the postorbital process.

shark

Answer 8

endolymphatic process

Question 9

most anterior of the two pairs of openings within the periphery of the endolymphatic fossa

Answer 9

endolymphatic foramen

Question 10

posterior paired opening to the endolymphatic foramen.

Answer 10

perilymphatic foramen

Question 11

a large region of teach side of the endolymphatic fossa behind the orbit.

Answer 11

otic capsule

Question 12

erminal opening shortly posterior to the endolymphatic fossa through which the brain continues with the spinal cord.

Answer 12

foramen magnum

Question 13

midventral longitudinal structure running from the anterior to the posterior portion of the rostrum.

Answer 13

rostral keel/carina

Question 14

ventrally directed opening leading internally towards the nasal capsule.

Answer 14

external naris

Question 15

median flat region immediately following the nasal capsule.

Answer 15

ethmoid plate

Question 16

located along the narrowed ventral walls of the two orbits, which furnishes articulation for the orbital processes of the upper jaw.

Answer 16

basitrabecular process

Question 17

broad flat surface posterior to the narrow ethmoid plate containing the following structures:

Answer 17

basal plate

Question 18

a seemingly straight strip of aberration appearing along the middle part of the basal plate. This is part of the notochord.

Answer 18

median streak

Question 19

slight paired projections emanating from the ventral surface of the foramen magnum.

Answer 19

occipital condyle

Question 20

first and largest of the gill arches that have been modified to serve as the upper and lower jaw. This is divided into two major components:

Answer 20

mandibular arch

Question 21

bears the teeth of the upper jaw and is attached to the chondrocranium by a ligament in live specimens.

Answer 21

paloquadrate/pterygoquadrate

Question 22

comprises the lower jaw of the animal joined by the angle of the mouth to the palatoquadrate.

Answer 22

Meckel’s cartilage

Question 23

– the 2nd of the gill arches immediately posterior to the mandibular arch and consists of the following:

Answer 23

hyoid arch

Question 24

a ventral median piece.

Answer 24

basihyal

Question 25

a slender bar on each side of the basihyal

Answer 25

ceratohyal

Question 26

a stout piece of cartilage found dorsal to each ceratohyal.

Answer 26

hyomandibular