vertebrate comparative anatomy of muscular system
TRANSCRIPT
COMPARATIVE ANATOMY OF VERTEBRATE MUSCULAR SYSTEM
BY
ADESEJI WASIU ADEBAYO
08/46KAOO6
ANA 814 – VERTEBRATE COMPARATIVE ANATOMY
DEPARTMENT OF ANATOMY,
UNIVERSITY OF ILORIN. L E C T U R E R : D R A . O. OY E W O P O
Muscular SystemFunctions◦ Locomotion
◦ Posture
◦ Protection
◦ Heat production and thermoregulation
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Vertebrate musclesVoluntary and involuntary
Striated and non striated
Skeletal, smooth and cardiac
Smooth muscle
Skeletal muscle
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Classification of Muscle
Skeletal
found in limbs
Cardiac
found in heart
Smooth
Found in
viscera
Striated, multi- nucleated Striated, 1
nucleus
Not striated, 1
nucleus
voluntary involuntary involuntary
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Muscle Control
Type of
muscle
Nervous
control
Type of
control
Example
SkeletalSkeletal Controlled
by CNS
Voluntary Lifting a
glass
CardiacRegulated
by ANS
Involuntary Heart
beating
Smooth Controlled
by ANS
Involuntary Peristalsis
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Muscles of Aquatic Vertebrates
The muscles of FISHES are less complex than in TETRAPODS.
Muscles of Aquatic Vertebrates
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AXIAL MUSCULATURE
2 divisions:◦Epaxial (Upper)◦Hypaxial (Lower)
◦ (+) Lateral septum◦ (+) Myomeres◦ (+) Myosepta
◦ MYOMERES become more angled (zig-zag shaped) and are molded into interlocking cones.
Muscles of Aquatic Vertebrates
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Muscles of Aquatic Vertebrates
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Strap-like hypobranchialmuscles extend from the pectoral girdle to the visceral arches.
◦ Serve to open the jaws and pull the gills downward and backward.
◦ Evolved from the hypaxialmuscles retaining the longitudinal orientation of fibers.
Muscles of Aquatic Vertebrates
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APPENDICULAR MUSCULATURE◦ (+) Paired appendages (evolved with fins)
Muscles of Aquatic Vertebrates
Dorsal mass of
EXTENSOR:
Abductors/Levators
Moving the fins UPWARD or FORWARD
A series of levatorsabove the pharynx lift the gill bars.
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Ventral mass of FLEXOR:
◦Adductors/Depressors
◦Moving the fins DOWNWARD or BACKWARD
◦Adductors reduced the internal angles of each visceral arch.
Muscles of Aquatic Vertebrates
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FISHES have 6 extrinsic eye muscles:
Muscles of Aquatic Vertebrates
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Muscles of Amphibians
Axial musculatureModified from lower aquatic forms
Metameric condition = obscure
Trunk reduced in volume
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URODELE AMPHIBIANSDo not have epaxial muscles
Their lateral septum is more dorsal in position
Myotomes are primitive
Muscle fibers still course form one myocommata to the next,
The entire epaxial mass formed dorsalis trunci
Myotomes – vertically arranged
Intersegmental bundles
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ANURANS AMPHIBIANSDorsalis trunci become differentiatedinto intertransversarial musclesbetween the transverse processesand interneural muscles betweenneural arches
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HYPAXIAL MUSCLES OF AMPHIBIANSADULT URODELES
Ventral trunk muscles
Beginning from the outside, there are superficial and deep external oblique (course in posteroventral direction)
Internal oblique layer extend in posterodorsal direction
Transversus which fibers almost in a vertical position. It lies next to peritoneum
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SPECIALIZED ANURANSReduced the number of layers in hypaxial trunk muscles
Rectus abdominis is large muscle extending from sternum to pubis
Myocommata have disappeared from the external oblique and transversus but are retained to some extent in the rectus abdominisas tendinous inscriptions
Lastly, the amphibians have muscle that move the to tongue this derived from the hypobranchial muscle
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AXIAL MUSCULATURE
Epaxial muscles
– functions to extend or straighten the spine and provide some lateral flexion.
– lack myosepta and become complex
Reptiles
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AXIAL MUSCULATURE
Hypaxial muscles – functions to bend the spine and provides lateral bending.◦subvertebral group
◦rectus abdominis group
◦ lateral group
Reptiles
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APPENDICULAR MUSCULATURE
more numerous and diverse than in AMPHIBIANS.
Intrinsic muscles
- quadrupedal locomotion◦Dorsal extensor◦Ventral flexor muscles
◦Extrinsic integumentary muscles -inserted on the underside of the dermis.
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Forelimbs
-trapezius muscles derived from the branchialmusculature
-several muscles derived from the axial musculature
-most appendicular muscles are derived directly from appendicular muscles of fish ancestors.
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Hindlimbs
-dorsal and ventral muscle groups are again recognized.
*caudofemoralis- a prominent flexor of the thigh of Reptiles.
Extrinsic eyeball muscles
Eyeball can no longer be rotated around its optical axis.
*pyramidalis-muscles inserted on the upper lids and nictitating membrane of Reptiles.
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Birds Muscular StructureMost birds have approximately 175 different muscles.
The skin muscles help a bird in its flight by adjusting the feathers.
Pygostyle (tail muscle)
The pectorals, or the breast muscles
True Flight
thin, stringy muscles of the vertebral column
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The supracoracoideus works using a pulley like system to lift the wing while the pectorals provide the powerful downstroke.
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Epaxial Muscle
– lack myosepta
– complex
Hypaxial Muscle
– same with all tetrapods
* subvertebral group
– located below transverse process
– ventroflexes the spine
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Anterior ribs
– enlarged
– penetrates external and internal obliques
– forms the intercostals muscle
– ventilation of the lungs
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Lateral group of hypaxial muscle:
- Serrratus
- Levator scapulae
- Rhomboideus
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Branchial muscle
*Ancestor adductor mandibulae of lower vertebrates several muscles in mammals
(-) depressor mandibulae
Digastric muscle (new muscle)
-ventral constrictor of 1st and 2nd arches innervated by 5th and 7th cranial nerves
Stapedial muscle
Muscle of the larynx
Constrictor of the throat36
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AXIALMUSCLES
FISHES AMPHIBIANS REPTILES BIRDS MAMMALS
Epaxial(Upper)
Solid mass; above the lateral septum
Muscle masses subdivided and rearranged into
longitudinal muscles
Muscle masses subdivided and rearranged into
longitudinal muscles
Muscle masses subdivided and rearranged into
longitudinal muscles
Hypaxial(Lower)
Solid mass; below the lateral septum
2 outer oblique layers; 1 inner
transverse layer; rectus abdominis
2 outer oblique layers and 1 innertransverse layer; rectus abdominis
2 outer oblique layers and 1 innertransverse layer; rectus abdominis
Oblique layers are further subdivided,
separated by intercostal muscles
SeptumTransverse/
Lateral septumDorsally position Linea alba
Myotomes Present Present Absent
Myosepta Present Present Absent Absent
FUNCTION
To produce an undulating motion
that propels the fish through the water
Maintenance of posture, head
movement, and respiration
Maintenance of posture, head
movement, and respiration
Maintenance of posture, head
movement, and respiration
Maintenance of posture, head
movement, and respiration
Comparative Anatomy of Vertebrates Muscular System 38
Epaxials (Tetrapods)
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Hypaxials (Tetrapods) 40
Hypaxials (Tetrapods) 41
Hypaxials (Tetrapods) 42
JAWMUSCLES
FISHES AMPHIBIANS REPTILES BIRDS MAMMALS
BranchiomericConstrictors and levator muscles
Associated with mandibular,hyoid and
pharyngeal arches
Associated with mandibular,hyoid and
pharyngeal arches
Associated with mandibular,hyoid and
pharyngeal arches
Highly modified; mandibular, hyoid and
pharyngeal arches
FUNCTIONBreathing and
feeding
Contribute to larynx
(vocalization) and throat
Contribute to larynx
(vocalization) and throat
Contribute to larynx
(vocalization) and throat
Control vocal functions within
larynx
HypobranchialAttached
posteriorly to pectoral skeleton
Associated withpharyngeal
arches
Associated withpharyngeal
arches
Associated withpharyngeal
arches
Associated withpharyngeal
arches
FUNCTION
Serve to open the jaws and pull
the gills downward and
backward
Movement of the larynx, hyoid
apparatus and tongue
Movement of the larynx, hyoid
apparatus and tongue
Movement of the larynx, hyoid
apparatus and tongue
Movement of the larynx, hyoid
apparatus and tongue
Comparative Anatomy of Vertebrates Muscular System
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Hypobranchial
muscles
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BRANCHIOMERIC MUSCLES46
HYPOBRANCHIAL MUSCLES47
APPENDICULARMUSCLES
FISHES AMPHIBIANS REPTILES BIRDS MAMMALS
Adductor muscles
Dorsal; flexfins
Ventral; recovery
Ventral; recovery
Ventral; recovery
Ventral; recovery
Abductor muscles
Ventral; extend fins
Dorsal;propulsive
Dorsal;propulsive
Dorsal;propulsive
Dorsal;propulsive
Other characteristics
Intrinsic muscles are
limited in number &
undifferentiated
Much more complex than
in fish
More numerous & diverse than
in amphibians
Intrinsic musculature is reduced
Similar to reptiles but
more diverse
FUNCTIONBalance and orientation
Support and locomotion
Support and locomotion
Support and locomotion
Support and locomotion
Comparative Anatomy of Vertebrates Muscular System
Recovery Phase- Forward movement and raising of the limb (adduction)– Flexing of arm/leg– Extension of hand/ foot
Propulsive Phase- Backward movement of the limb (abduction)– Extension of arm/leg– Flexion of hand/foot 48
Muscles responsible for
Amphibians Reptiles Mammals
Forelimb abduction
Latissimus dorsi Latissimus dorsiLatissimus dorsi;
Trapezius
Hindlimbabduction
Caudofemoralis CaudofemoralisCaudofemoralis;Biceps femoralis
Propulsive Phase:
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INTEGUMANTARYMUSCLES
REPTILES BIRDS MAMMALS
Specialized Muscles Costo-cutaneous musclesArrector pilli muscles;
patagial muscles
Arrector pilli muscles;patagial muscles
(bats);mimetic muscles
FUNCTIONProvide friction for
locomotionAid in flight control
Involved in facial expression
Comparative Anatomy of Vertebrates Muscular System
Patagial muscles
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