Lecture 13

Question 1

Which muscle group is derived directly from myotome portions of somites?

Answer 1

axial

Question 2

What is metamerism?

Answer 2

segmental arrangement

Question 3

WHich muscle groups display a metamerism?

Answer 3

axial and branchiometric

Question 4

Which muscles are innervated by spinal nerves?

Answer 4

axial and appendicular

Question 5

Branchiometric muscle groups are formed from

Answer 5

formed from embryonic mescenchyme associated with the pharyngeal arches.

Question 6

Which muscle group is innervated by cranial nerves

Answer 6

branchiomeric

Question 7

What do appendicular muscle groups form from?

Answer 7

limb bud mesenchyme

Question 8

In gnathostomes axial muscles are typically divided into

Answer 8

• epaxial (more dorsal) and hypaxial (more ventral) muscles.

Question 9

The Epaxial and Hypaxial parts are separated form each other by….

Answer 9

a fibrous tissue partition called the horizontal septum

Question 10

the horizontal septum is not present in

Answer 10

cyclostomes

Question 11

What separates individual myomers?

Answer 11

transverse septa

Question 12

What innervates the lateral rectus muscle?

Answer 12

Abducens CN VI

Question 13

What innervates the superior oblique?

Answer 13

Trochlear nerve CN IV

Question 14

What does the occulomotor nerve (CNIII) Innervate?

Answer 14

♣ Inferior rectus
♣ Medial rectus
♣ Inferior rectus
♣ Inferior oblique

Question 15

What is a myomere?

Answer 15

segments that make up the axial musculature

Question 16

Describe the axial musculature of the amphibian and relate to that of a fish:

Answer 16

Reduction in epaxial muscles
Division of hypaxial mm into layers
Increase in mass and complexity of limb muscles.

NOTE: Fish need to have the axial musculature to swim… the lizards and crap need to use their limbs to get around.

Question 17

describe the axial musculature of an amniote (reptile and mammal) and relate to that of a typical fish and an amphibian.

Dorsalis truncus subdivided into 3 longitudinal columns named:

Answer 17

transversospinalis
Longissiumus dorsi
Iliocostalis

Question 18

Epaxial muscles are reduced in what reptile?

Answer 18

turtles

Question 19

Hypaxial layers are divided into three layers as in

Answer 19

amphibians

Question 20

Thoracic region:

Answer 20

external oblique

• supracostals
• innercostals

Internal oblique
-deeper intercostals

Transversus
-subcostals

Question 21

Escribe Epaxial:

Answer 21

intrinsic
deep
above dorsal ribs and vertebral transverse processes
innervated by dorsal rami of spinal nerves

Question 22

Descrive hypaxial

Answer 22

extrinsic
superficial
below dorsal ribs and lateral to the ventral ribs if present
innervated by the ventral rami of spinal nerves

Question 23

superficial back muscles:

Answer 23

splenius capitis

splenius cervicis

Question 24

intermediate back muscles

Answer 24

iliocostalis
longissiumus
spinalis

Question 25

deep back muscles:

Answer 25

semispinalis
multifidus
rotatores

Question 26

Muscles of the gill arch region arise form the _______________ embryonic mesenchyme instead of somites.

Answer 26

embryonic mesenchyme

Question 27

Gill arch I is called

Answer 27

mandibular

Question 28

what innervates the gill arch I

Answer 28

CN V trigeminal

Question 29

Gill arch II is called

Answer 29

hyoid

Question 30

What innervates gill arch II?

Answer 30

CN VII facial nerve

Question 31

Gill arch III is innervated by

Answer 31

CN IX: Glossopharyngeal nerve

Question 32

all the remaining gill arches are innervated by

Answer 32

CN X: Vagus nerve

Question 33

Function of mammalian masseter:

Answer 33

Elevates and protracts mandible

Question 34

function of mammalian temporalis:

Answer 34

elevates and retracts mandible

Question 35

function of lateral pterygoid

Answer 35

protracts mandible, depresses chin (bilateral; grinding (unilateral))

Question 36

Function of mammalian pterygoid:

Answer 36

elevates, protracts, grinding (unilateral)

Question 37

All the muscles of mastication are innervated by which nerve?

Answer 37

CN V

Question 38

Attachments for masseter:

Answer 38

zygomatic bone to lateral surface of ramus and coronoid process

Question 39

attachments for temporalis:

Answer 39

temporal fossa and fascia to coronoid process

Question 40

attachments lateral pterygoid

Answer 40

lateral pterygoid plate and sphenoid to front of mandible and TMJ

Question 41

attachments of medial pterygoid:

Answer 41

lateral pterygoid plate and maxilla to medial surface of mandible near angle.

Question 42

Why does the diagastric muscle have 2 sources of innervation?

Answer 42

has 2 bellies:

Anterior: supplied by trigeminal via the myohyoid nerve, a branch of the inferior alveolar nerve, itself a branch of the mandibular division of the trigeminal nerve.

Posterior belly: supplied by the digastric branch of the facial nerve