Vertebrates 10 - Muscular Classes

Question 1

Muscle classification

Answer 1

Visceral (GI tract, CV system) and somatic (limbs, body wall)

Question 2

Somatic muscle subdivisions

Answer 2

Axial, appendicular (limbs), branchiomeric (visceral arches, jaws)

Question 3

How do muscles connect to bone?

Answer 3

Usually tendons, sometimes a thin flat tendon called aponeurosis (like in hand)

Question 4

Skeletal muscle types

Answer 4

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

Question 5

Myoglobin

Answer 5

Globin in muscle that binds oxygen temporarily in muscle. More myoglobin means it can better utilize oxygen

Question 6

Tuna muscle

Answer 6

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

Question 7

Muscle pairs

Answer 7

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

Question 8

Chondrichthyes branchiomeric

Answer 8

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

Question 9

Amphibian branchiomeric

Answer 9

Upper jaw is fused to skull, don’t need muscles there. Depressor mandibulae is small, opens jaw. Adductor mandibulae is a group.

Question 10

Branchiomeric muscles in birds and reptiles

Answer 10

Pretty similar to amphibia, biggest are to close the jaw. Same names/groups

Question 11

Mammalian Branchiomeric muscles

Answer 11

Digastric (small, opens jaw). Temporalis (insert in coronoid process)and masseter (found in cheek, origin at zygomatic arch)

Question 12

Herbivores vs carnivores

Answer 12

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

Question 13

Axial somatic muscles

Answer 13

Associated with the axial skeleton: body wall,

Question 14

Axial muscles in fish

Answer 14

Two groups: epaxial (upper)and hypaxial. Thick. Muscles divide into myomeres (zigzag) connected by myosepta. Myofibers arranged longitudinally. Determines the locomotion

Question 15

Basic locomotion of fish

Answer 15

Myomeres contract in two regions: one on side at front and other side caudally. Makes the S shape.

Question 16

Axial muscles in tetrapods (salamander)

Answer 16

Body wall muscles thinner. Epaxial are more dorsal, smaller. Hypaxial have divisions and layers. More support and important in locomotion

Question 17

Axial muscle layers in tetrapods (salamander)

Answer 17

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.

Question 18

Axial muscles in mammals (cat)

Answer 18

External oblique, internal oblique, transversus, pretty much same. Thinner. Function in support

Question 19

Which animal has the thinnest muscle sheets (relatively)

Answer 19

Cat. Shark had thickest

Question 20

Appendicular muscles of fish

Answer 20

Ventral muscle (Flexor) and Dorsal muscle (extensor). Don’t move the fin a lot.

Question 21

Appendicular muscles of tetrapod (amphibia and reptile)

Answer 21

New joints/bones. Deltoid and latissimus dorsi are dorsal; triceps, biceps and pectoral. Not very big in aquatic animals.

Question 22

Functions of appendicular muscles in reptiles/amphibia

Answer 22

Deltoid: up and forward; Lats: up and back; Tricep: extends limb; Biceps: supports lifting; Pectoralis: adductor.

Question 23

Appendicular muscles of mammals (cat)

Answer 23

Trapezius, latissimus dorsi, deltoids, triceps. Biceps is not very strong. Deltoids just support, don’t abduct much. Motion is directly under cat.

Question 24

Appendicular muscles of flight

Answer 24

Pectoralis (downstroke, much larger relatively); and supracoracoideus (upstroke, smaller, under pec. and pulls up on humerus)

Question 25

EMG on birds

Answer 25

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