Vertebrates 10 - Muscular Classes Flashcards Preview

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Flashcards in Vertebrates 10 - Muscular Classes Deck (25)
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Muscle classification

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


Tuna muscle

Need to constantly swim to live. Have column of red muscle inside for constant movement, and white muscle outside for speed


Muscle pairs

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


Chondrichthyes branchiomeric

Levator palatoquadrate = lifts upper jaw; coracomandibularis = open lower jaw; adductor mandibulae = closes the lower jaw strong to eat


Amphibian branchiomeric

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)


EMG on birds

Measured with wires on birds flying in wind tunnels. Increase in electrical activity measured before the up or downstroke. Why? Delay in contraction.