Muscles 1 Flashcards
Function of axial muscles in birds & mammals
Epaxial stabilize vertebral column
Hypaxials for protective body wall (esp. in lumbar region - no ribs), 3 layers hold in viscera & move trunk - all tetrapods
Hypaxials expand/compress ribcage for ventilation - all amniotes
Describe the appendicular muscles of anurans
(frogs, toads) large, for jumping
Function of muscles
Provide force for movement - skeletal or internal
Where does the muscle in the walls of blood vessels come from?
Either mesenchyme or splanchnic hypomere mesoderm
Function of hypobranchial muscles in jawed fish?
- open jaw
- move tongue
- expand buccal & branchial cavities
Which muscles does splanchnic hypomere mesoderm give rise to?
Cardiac
Smooth around some blood vessels & in digestive tract lining
From where do hypobranchial muscles arise?
anterior/ventral growth of somites
Describe the appendicular muscles of caecilians
None - 2° loss (use lateral undulation)
How are axial muscles divided?
Into myomeres along length of body
Epaxial above horizontal septum, hypaxial below
Function of branchiomeric muscles in tetrapods
open/close mouth
in middle ear
facial muscles
muscles for branchial arches III-VII reduced, in larynx/pharynx/pectoral girdle & forelimbs
Where does the smooth muscle around the digestive tract come from?
Some from splanchnic hypomere mesoderm, some (around visceral organs) from mesenchyme
Axial muscle function in tetrapods with sprawled limb posture
Provide force for lateral undulation (locomotion not taken over by limbs)
Which muscles does myotome epimere mesoderm (somites) give rise to?
Most skeletal muscle (axial & appendicular), hypobranchial (from anterioventral growth)
Describe the appendicular muscles of tetrapods, in general
more prominent than in fish & divided into several groups for complex motion; even helped by some axial (& branchial, in forelimbs) muscles
General function of branchiomeric muscles
Form muscular pharyngeal pump by attaching to splanchnocranium branchial arches
Function of branchiomeric muscles in chondrichthyes & osteichthyes
Pump water over gills & move jaws
Where are hypobranchial muscles found in tetrapods?
Larynx, tongue, throat, hyoid apparatus
Where does cardiac muscle come from?
splanchnic hypomere mesoderm
Describe the appendicular muscles of fish
Small, on top & bottom of fins connecting girdle to pterygiophores
Axial muscle function in amniotes
Hypaxials for protective body wall (esp. in lumbar region w/o ribs), in 3 layers to hold in viscera & move trunk - all tetrapods
Also expand/compress ribcage for ventilation
Describe the appendicular muscles of salamanders
Diversified (as in all tetrapods), but small because still primarily use lateral undulation for locomotion
List the 5 types of antagonistic muscle pairs
- Abduction/adduction
- Flexion/extension
- Protraction/retraction
- Levation/depression
- Constriction/dilation
Which types of muscles does mesenchyme give rise to?
Smooth in walls of some blood vessels & visceral organs
What gives rise to branchiomeric muscles & extrinsic eye muscles?
Somitomeres in head
Where does most skeletal muscle come from?
Myotome epimere mesoderm in somites
Describe the appendicular muscles of birds & cursorial tetrapods
Mass concentrated proximally to reduce distal mass and improve efficiency (also makes birds more stable in flight)
Connected to distal sites by tendons
Function of axial muscles in tetrapods
Hypaxials for protective body wall (esp. in lumbar region w/o ribs), in 3 layers to hold in viscera & move trunk
Function of branchiomeric muscles in agnathans
pump water over gills
