Chapter 10 Part 3

Question 1

External intercostals

Answer 1

muscle associated with ribs, run from one rib to another, diagonal orientation opposite from internal intercostals

Question 2

internal intercostals

Answer 2

run from one rib to another in the opposite direction of external intercostals

Question 3

transversus

Answer 3

3rd layer of hypaxial muscles, runs vertical to external and internal intercostals

Question 4

Hypaxial muscles in tetrapods for thorax

Answer 4

external intercostals, internal intercostals, transversus

Question 5

hypaxial muscles in abdomen in tetrapods

Answer 5

external oblique, internal oblique, transversus, rectus abdominis

Question 6

Hypobranchial muscles: which group of axial muscles are they derived from?

Answer 6

ventral myotomes of somites (mesoderm)

Question 7

· What is the function of the muscular sling?
o Which muscles are branchiomeric in origin?

Answer 7

muscular sling in vertebrates, particularly in the pectoral girdle, serves to suspend and stabilize the forelimbs, allowing for complex movements and support during locomotion.

branchiomeric in origin: generally face muscles (eyes, facial expressions, jaw)

Question 8

· Why is there no muscular sling in the hindlimb?

Answer 8

evolutionary emphasis for hindlimbs has been on stability and the ability to generate powerful, propulsive forces for movements such as running, jumping, or walking. As a result, the hindlimbs are directly attached to the axial skeleton through the pelvic girdle, which provides a more rigid and stable connection. This direct attachment eliminates the need for a complex muscular sling

Question 9

Understand the major muscle groups associated with:
Pharyngeal arch I (the mandibular arch)

Answer 9

• craniel nerve V (trigeminal nerve)
• muscle that close lower jaw
• levator palatoquadrati, abduuctor mandibularis, intermadibularis

Question 10

Understand the major muscle groups associated with:
Pharyngeal arch II (the hyoid arch)

Answer 10

-levator hyomadibulae and epihyoiden
- ventral constrictor hyoideus(constrictor colli): sheet of throat muscle (example: elepahnt trunk muscles, longitduinal radial and helical)
- muscles of facial expression

Question 11

Understand the major muscle groups associated with:
Pharyngeal arches III-VI

Answer 11

• cranial nerves IX, X, XI
• Each arch has levator and constrictor muscles that, respectively, elevate and close the articulated elements

IX – Glossopharyngeal
X – Vagus
XI – spina laccessory

Question 12

Understand the major muscle groups associated with:

Which cranial nerve or nerves are associated with each?

Question 13

Understand how the anteriormost somitomeres produce the extrinsic eye

Question 14

Extrinsic eye muscles and how they arose

Answer 14

The most anterior somitomere of the three gives rise to the superior, inferior, and medial rectus and to the inferior oblique muscles, all supplied by the third (III) cranial nerve

The next somitomere gives rise to the superior oblique, supplied by the fourth (IV) cranial nerve

The third somitomere gives rise to the lateral rectus, supplied by the sixth (VI) cranial nerve

Question 15

Describe examples of electric organs

Answer 15

In the torpedo, skate, electric eel, and electric catfish, these electric organs can produce a jolt of voltage sufficient to stun prey or discourage a predator’s attack

In other fishes, the electric organs produce a weak electric field around the fish’s body, allowing it to detect any object that disrupts the field

In this way, fishes with electric fields can navigate and find food in dark or silty waters