Lecture 6 Flashcards
all vertebrates have what types of muscles?
- skeletal
- cardiac
- smooth
skeletal, cardiac and smooth muscles are derived from ——-
mesoderm
what is rule #1 about muscle phylogeny?
muscles and skeleton go together <3
the facial muscles, platysma, attaches where?
not to the skeleton but to the skin
you only find platysma where?
mammals
platysma is derived from what muscle in the shark and salamander?
levator hyomandibulae
Muscles attach to bones via what?
tendons
muscles attack to bone via ——
tendons
muscles are found in———— pairs
antagonistic
there are two quite distinct developmen patterns within the body:
- Muscle in trunks and limbs are derived from somites
2. Muscle in head and pharyngeal arches from somitomeres.
How can we tell epaxial from hypaxial muscle groups in adult amniotes?
by their nervous innervation.
what is rule #2 about muscle phylogeny?
nerve supply is very useful to identify embryonic origin of a muscle.
what is rule #3 about muscle phylogeny?
when it comes to brnachiomeric muscles, there is lots of muscles and therefore lots of evolution
why add muscles to support the pectoral girdle?
because the pectoral girdle is not fused to the vertebral column.
Salatory (jumping) mode:
big emphasis on axial (dorsal trunk) and hind limb muscles.
Cursial mode:
Big emphasis on girdle and limb muscles. They keep limb muscles proximal to body to reduce weight of limbs. Use tendons to lengthen lever (long legs) and finally reduce number of digits to increase speed.
Flight Mode:
Big emphasis on pectoral muscles and attachment points. The down stroke always generates lift. Additionally, want to lighten and fuse skeleton wherever possible.
what is rule #4 in muscle phylogeny?
appendicular muscles have been extensively remodeled during evolution to support a variety of locomotory styles. Ex.) if there is one muscle in necturus look for 2 or even 4 in a cat.
