Comparative AnatomyComparative AnatomyMusclesMuscles

Kardong Kardong Chapter 10Chapter 10

Part 10

MusclesMuscles

Two major muscle categories:Two major muscle categories: Somatic musclesSomatic muscles

Operate head, trunk, limbsOperate head, trunk, limbs Locomotion and orientationLocomotion and orientation

Visceral musclesVisceral muscles Operate visceral skeletonOperate visceral skeleton Digestion and respiratory movementsDigestion and respiratory movements

More on the two Muscle More on the two Muscle GroupingsGroupings

Somatic musclesSomatic muscles Skeletal muscleSkeletal muscle Striated and voluntaryStriated and voluntary

Visceral musclesVisceral muscles Smooth muscleSmooth muscle Non-striated and involuntaryNon-striated and involuntary Exception- branchiomerics (unsegmented)Exception- branchiomerics (unsegmented)

Skeletal Muscle Microanatomy

Figure 10.1 (book figure 10.2).

Cardiac Muscle Microanatomy

Figure 10.2 (book figure 10.3).

Smooth Muscle Microanatomy

Figure 10.3 (book figure 10.4).

Skeletal MusclesSkeletal Muscles

AxialAxial Trunk and tailTrunk and tail

AppendicularAppendicular Insert on girdles, fins, or limbsInsert on girdles, fins, or limbs

BranchiomericsBranchiomerics Attached to visceral skeletonAttached to visceral skeleton

Figure 10.4. (book figure 10.21).

Origin of Muscle GroupsDerived from Embryonic

Myotomes

Axial MusculatureAxial Musculature SharkShark

Epaxial and hypaxial Epaxial and hypaxial musclesmuscles

Body wall musclesBody wall muscles AmphibiansAmphibians

Epaxials above Epaxials above transverse processtransverse process

Hypaxials along body Hypaxials along body wall properwall proper

MammalsMammals Epaxials subdividedEpaxials subdivided Hypaxials more complexHypaxials more complex

Figure 10.5. Trunk muscles of vertebrates.

Abdominal Muscle Groups - AmniotesAbdominal Muscle Groups - Amniotes

EpaxialsEpaxials Transversospinalis, Transversospinalis,

longissimus, iliocostalislongissimus, iliocostalis HypaxialsHypaxials

Dorsomedials, laterals, Dorsomedials, laterals, ventralsventrals

Laterals- external oblique, Laterals- external oblique, internal oblique, and internal oblique, and transverse abdominustransverse abdominus

Ventral- rectus abdominusVentral- rectus abdominus

Figure 10.6. Epaxial and hypaxial muscles

Epaxial and Hypaxial Muscles - AmniotesEpaxial and Hypaxial Muscles - Amniotes

Figure 10.7. Epaxial and hypaxial mucles.Figure 10.8. Specific epaxial muscles.

Head RegionHead Region

Figure 10.10. Axial muscle origin and innervation in vertebrate embryo.

Figures 10.9. Myotomes in the head, neck, and thoracic regions of the embryo.

Head RegionHead Region In branchial region, somites are broken downIn branchial region, somites are broken down Ventral slips of postbranchial somites become Ventral slips of postbranchial somites become

hypobranchialhypobranchial musculature musculature Hypobranchial muscles give rise to:Hypobranchial muscles give rise to:

SternohyoidSternohyoid SternothyroidSternothyroid OmohyoidOmohyoid Tongue muslcesTongue muslces

GeniohyoidGeniohyoid HyoglossusHyoglossus StyloglossusStyloglossus GenioglossusGenioglossus Lingualis propriaLingualis propria

Figure 10.11. (book figure 10.30).

Appendicular MusclesAppendicular Muscles

ExtrinsicExtrinsic Origin on axial skeleton or fascia of trunkOrigin on axial skeleton or fascia of trunk Insert on girdles and limbsInsert on girdles and limbs

IntrinsicIntrinsic Origin on girdles or proximal skeletal elements of Origin on girdles or proximal skeletal elements of

appendagesappendages Insert on more distal skeletal elementsInsert on more distal skeletal elements

Intrinsic MusclesIntrinsic Muscles

Figure 10.12. Intrinsic muscles of pectoral girdle and forelimbs of mammals and their homologues in reptiles.

BranchiomericsBranchiomerics

Arises from lateral mesodermArises from lateral mesoderm Mandibular (1Mandibular (1stst) arch) arch Hyoid archHyoid arch Arches IV to VIArches IV to VI

Branchiomeric MusclesBranchiomeric Muscles

Figure 10.13. Branchiomeric muscles and their innervations (see book table 10.3).

BranchiomericsBranchiomerics Mandibular (1Mandibular (1stst) arch) arch

Intermandibularis - digasticIntermandibularis - digastic Adductor mandibulae - masseter, temporalisAdductor mandibulae - masseter, temporalis

Hyoid archHyoid arch Sphincter coliSphincter coli Platysma and mimeticsPlatysma and mimetics

integumentary musclesintegumentary muscles Arches IV to VIArches IV to VI

Trapezius, sternomastoid, Trapezius, sternomastoid, cleidomastoidcleidomastoid

Figure 10.14. Branchiomeric muscles of gnathostomes.

Nerves Innervating MusclesNerves Innervating Muscles

Figure 10.15. Facial nerves to muscles.

Figure 10.16. Cranial nerves.

Extrinsic Eye MusclesExtrinsic Eye Muscles

Six eyeball musclesSix eyeball muscles 2 obliques2 obliques

Superior and inferior on Superior and inferior on anterior portionanterior portion

4 rectus4 rectus Arise in posterior Arise in posterior

portion of orbitportion of orbit Innervated by Innervated by

oculomotor, trochlear, oculomotor, trochlear, and abducensand abducens

Figure 10.17. Innervation of eye muscle in embryo.

Extrinsic Eye MusclesExtrinsic Eye Muscles

Figure 10.18. Dorsal view of extrinsic muscles of the left eyeball . Figure 10.19. Lateral view of extrinsic

muscles of eyeball.

DiaphragmDiaphragm

Mammalian muscle structureMammalian muscle structure Near lungs and heart in abdominal cavityNear lungs and heart in abdominal cavity

Figure 10.20. Human diaphragm.

Dermal or Integumentary MusclesDermal or Integumentary Muscles

Fish & tailed amphibians- Fish & tailed amphibians- skin is firmly attached to skin is firmly attached to musculaturemusculature

Sphincter coli- first Sphincter coli- first muscle to move skinmuscle to move skin Subdivides down neck- Subdivides down neck-

platysmaplatysma Extrinsic and intrinsic Extrinsic and intrinsic

muscle groupsmuscle groups Figure 10.21. Evolution of mammalian facial muscles. Shows sphincter colli (SC) spreading into platysma (P).

ExtrinsicExtrinsic Integumentary Muscles Integumentary Muscles Costocutaneous muscles - allows rectilinear motion Costocutaneous muscles - allows rectilinear motion

(reptiles)(reptiles) Panniculus carnosus - sheet surrounds bodyPanniculus carnosus - sheet surrounds body Cutaneous maximus - to shake skin (higher mammals)Cutaneous maximus - to shake skin (higher mammals) Patagial muscles - bat wingsPatagial muscles - bat wings Auricularis - moves human earAuricularis - moves human ear Caninus muscle - arises with aggressionCaninus muscle - arises with aggression

IntrinsicIntrinsic Integumentary Muscles Integumentary Muscles Arrectores plumarum (birds) & arrectores pilorum Arrectores plumarum (birds) & arrectores pilorum

(mammals) - erects hair and feathers(mammals) - erects hair and feathers

Specialized MusclesSpecialized Muscles

Electric organsElectric organs In elasmobranchs and bony fishIn elasmobranchs and bony fish Modified hypaxial musclesModified hypaxial muscles

Figure 10.22. Electric eel.

Vertebrates with Electric Organs

Figure 10.23. (book figure 10.1).