Flashcards in Vertebrates 10 - Muscular Classes Deck (25)
Visceral (GI tract, CV system) and somatic (limbs, body wall)
Somatic muscle subdivisions
Axial, appendicular (limbs), branchiomeric (visceral arches, jaws)
How do muscles connect to bone?
Usually tendons, sometimes a thin flat tendon called aponeurosis (like in hand)
Skeletal muscle types
Slow-twitch (red) and fast-twitch (white). Refers to myoglobin content (redder), speed of contraction. (there are gradients but who needs those). Marathoners or caribou have more slow-twitch, cheetah or sprinters have more fast-twitch
Globin in muscle that binds oxygen temporarily in muscle. More myoglobin means it can better utilize oxygen
Need to constantly swim to live. Have column of red muscle inside for constant movement, and white muscle outside for speed
Extensor/flexor; adductor/abductor = away/toward midline; levator/depressor = ; rotator = pronator/suppination (palm down, up); protractor/retract = towards/away from body; sphincter/dilator = close/open
Levator palatoquadrate = lifts upper jaw; coracomandibularis = open lower jaw; adductor mandibulae = closes the lower jaw strong to eat
Upper jaw is fused to skull, don’t need muscles there. Depressor mandibulae is small, opens jaw. Adductor mandibulae is a group.
Branchiomeric muscles in birds and reptiles
Pretty similar to amphibia, biggest are to close the jaw. Same names/groups
Mammalian Branchiomeric muscles
Digastric (small, opens jaw). Temporalis (insert in coronoid process)and masseter (found in cheek, origin at zygomatic arch)
Herbivores vs carnivores
Herbivores have small temporal fenestra and temporalis (doesn’t take much power to clip off grass), larger masseter (side to side for grinding). Horse has huge bottom jaw for insertion of masseter
Axial somatic muscles
Associated with the axial skeleton: body wall,
Axial muscles in fish
Two groups: epaxial (upper)and hypaxial. Thick. Muscles divide into myomeres (zigzag) connected by myosepta. Myofibers arranged longitudinally. Determines the locomotion
Basic locomotion of fish
Myomeres contract in two regions: one on side at front and other side caudally. Makes the S shape.
Axial muscles in tetrapods (salamander)
Body wall muscles thinner. Epaxial are more dorsal, smaller. Hypaxial have divisions and layers. More support and important in locomotion
Axial muscle layers in tetrapods (salamander)
Epaxial are dorsal. Hypaxial: Subvertebralis, External oblique, internal oblique, transversus. External and internal work together to create bending (S shape). Transversus helps stabilize and helps exhale.
Axial muscles in mammals (cat)
External oblique, internal oblique, transversus, pretty much same. Thinner. Function in support
Which animal has the thinnest muscle sheets (relatively)
Cat. Shark had thickest
Appendicular muscles of fish
Ventral muscle (Flexor) and Dorsal muscle (extensor). Don’t move the fin a lot.
Appendicular muscles of tetrapod (amphibia and reptile)
New joints/bones. Deltoid and latissimus dorsi are dorsal; triceps, biceps and pectoral. Not very big in aquatic animals.
Functions of appendicular muscles in reptiles/amphibia
Deltoid: up and forward; Lats: up and back; Tricep: extends limb; Biceps: supports lifting; Pectoralis: adductor.
Appendicular muscles of mammals (cat)
Trapezius, latissimus dorsi, deltoids, triceps. Biceps is not very strong. Deltoids just support, don’t abduct much. Motion is directly under cat.
Appendicular muscles of flight
Pectoralis (downstroke, much larger relatively); and supracoracoideus (upstroke, smaller, under pec. and pulls up on humerus)