Lecture Exam 2 Flashcards
what are the functions of ribs in amniotes?
support trunk muscles and lung ventilation
what do ribs articulate with?
transverse process
what is different about chondrichthyes ribs?
1 set of ribs
go from vertebrae to horizontal septum
what do chondrichthyes vertebrates do?
support epaxial muscles
and trunk muscles below the horizontal septum (hypaxial muscles)
what is special about seahorses?
NO RIBS
what are the ribs like in bony fishes?
connect vertebrae to myosepta of ventral body wall
support hypaxial muscles
what is special about
~some~ actinopterygii?
have 2 sets of ribs, ventral and dorsal
most only have ventral
what are the ribs in tetrapods?
1 set
bicipetal ribs
what are bicipetal ribs?
2 heads
tuberculum (transverse process) and capitulum (centrum)
what are amphib ribs like?
short
fused to transverse process
how are ribs laid out in amniotes?
2 parts: costal and sternal
what is the difference between the costal and sternal parts of amniote ribs?
costal is next to the vertebrae
sternal is ventral and attached to sternum
What is it called when sternal ribs are cartilaginous?
costal cartilage
what is the structure of ribs in birds?
bony sternal ribs
costal ribs have uncinate process (rearward projection of bone)
what is the function of bird ribs?
brace the trunk
what groups have sterna?
only tetrapods
lacking in fish
what is sterna made of and what is its function?
endochondral bone
support pectoral girdle and ribs
describe the structure of different groups sterna
amphibs: absent or poorly developed
salamanders: weak, only 1 bone
frogs/toads: more developed/stronger, 4 bones
why do frogs/toads have a more developed sterna?
land on forelimbs and need to absorb the impact
what does the sterna look like/do in amniotes?
it is well developed
allows for increased use of forelimbs in locomotion
what group lacks sterna?
snakesssss
what does the sterna look like in birds?
keeled sternum
very deep
why do birds have such specialized sterna?
for flight muscle attachment
describe the 3 birds and sterna types discussed in class?
roughed grouse (state bird): strong sterna
ostrich: flat sterna
penguins: keeled sterna