Comparative Anatomy Muscles Note Set 8 Chapter 10

Muscles Two muscle groups: Somatic muscles Visceral muscles Operate head, trunk, limbs Locomotion and orientation Visceral muscles Operate visceral skeleton Digestion and respiratory movements

Cranial Nerves to Muscles Figure 10.1: Facial nerves to muscles Figure 10.2: Cranial nerves

Two Muscle Types Somatic muscles Visceral muscles Skeletal muscle Striated and voluntary Visceral muscles Smooth muscle Non-striated and involuntary Exception- branchiomerics (unsegmented)

Skeletal Muscles Axial Appendicular Branchiomerics Trunk and tail Insert on girdles, fins, or limbs Branchiomerics Attached to visceral skeleton

Axial Shark Amphibians Mammals Epaxial and hypaxial muscles Body wall muscles Amphibians Epaxials above transverse process Hypaxials along body wall proper Mammals Epaxials subdivided Hypaxials more complex Figure 10.3: Trunk muscles of vertebrates.

Hypaxial and Epaxial Muscles Figure 10.5: Specific epaxial muscles Figure 10.4: Epaxial and hypaxial mucles

Abdominal Muscle Groups in Amniotes Epaxials Transversospinalis, longissimus, iliocostalis Hypaxials Dorsomedials, laterals, ventrals Laterals- external oblique, internal oblique, and transverse abdominus Ventral- rectus abdominus Figure 10.6: Epaxial and hypaxial muscles

Head Region Figures 10.7: Myotomes in the head, neck, and thoracic regions of the embryo. Figure 10.8- Axial muscle origin and innervation in vertebrate embryo.

Head Region In branchial region, somites are broken down Ventral slips of postbranchial somites become hypobranchial musculature Hypobranchial muscles give rise to: Sternohyoid Sternothyroid Omohyoid Tongue muslces Geniohyoid Hyoglossus Styloglossus Genioglossus Lingualis propria

Appendicular Muscles Extrinsic Intrinsic Origin on axial skeleton or fascia of trunk Insert on girdles and limbs Intrinsic Origin on girdles or proximal skeletal elements of appendages Insert on more distal skeletal elements

Intrinsic Muscles Figure 10.9: Intrinsic muscles of pectoral girdle and forelimbs of mammals and their homologues in reptiles.

Branchiomerics Arises from lateral plate mesoderm Mandibular (1st) arch Hyoid arch Arches IV to VI

Branchiomerics Mandibular (1st) arch Hyoid arch Arches IV to VI Intermandibularis- digastic Adductor mandibulae- masseter, temporalis Hyoid arch Sphincter colli Platysma and mimetics integumentary muscles Arches IV to VI Trapezius, sternomastoid, cleidomastoid Figure 10.10: Branchiomeric muscles of gnathostomes.

Branchiomeric Muscles Figure 10.11: Branchiomeric muscles and their innervations.

Extrinsic Eye Muscles Six eyeball muscles 2 obliques 4 rectus Superior and inferior on anterior portion 4 rectus Arise in posterior portion of orbit Innervated by oculomotor, trochlear, and abducens Figure 10.12: Innervation of eye muscle in embryo.

Extrinsic Eye Muscles Figure 10.13: Dorsal view of extrinsic muscles of the left eyeball. Figure 10.14: Lateral view of extrinsic muscles of eyeball in humans.

Diaphragm Mammalian muscle structure Covers lungs and heart in abdominal cavity Figure 10.15: Human diaphragm.

Dermal or Integumentary Muscles Fish & tailed amphibians- skin is firmly attached to musculature Sphincter colli- first muscle to move skin Subdivides down neck- platysma Extrinsic and intrinsic muscle groups Figure 10.16: Evolution of mammalian facial muscles. Shows sphincter colli (SC) spreading into platysma (P).

Extrinsic Integumentary Muscles Intrinsic Integumentary Muscles Costocutaneous muscles- allows rectilinear motion (reptiles--snakes) Panniculus carnosus-sheet surrounds body Cutaneous maximus- to shake skin (higher mammals) Patagial muscles- bat wings Auricularis- moves human ear Caninus muscle- arises with aggression Intrinsic Integumentary Muscles Arrectores plumarum (birds) & arrectores pilorum (mammals)- errects hair and feathers

Specialized Muscles Electric organs In fish Modified hypaxial muscles Figure 10.17: Electric eel.

Literature Cited Figure 10.1- http://www.city.ac.uk/optometry/Biolabs/cranial%20nerves/cranial_nerves_lab.htm Figure 10.2- http://mywebpages.comcast.net/epollak/PSY255_pix/PSY255_pix.htm Figure 10.3, 10.8, 10.9, 10.11, 10.12, 10.13, 10.16- Kent, George C. and Robert K. Carr. Comparative Anatomy of the Vertebrates. 9th ed. McGraw-Hill, 2001. Figure 10.4 & 10.5- http://www.mut.ac.th/~vet/Anat-html/muscle/muscle.html Figure 10.6, 10.10- http://people.eku.edu/ritchisong/342notes6.htm Figure 10.7- http://connection.lww.com/products/sadler/imagebank.asp Figure 10.14- http://www.bmb.leeds.ac.uk/illingworth/motors/myosin.htm Figure 10.15- http://whyfiles.org/204endurance_training/2.html Figure 10.17- http://www.aqua.org/animals_electriceel.html