final exam muscular system

Question 1

what do somites form?

Answer 1

skin, muscles and skeleton

Question 2

the muscular system develops from which layer?

Answer 2

mesoderm layer

Question 3

muscles are formed from which layer of the dermamyotome layer of the somite?

Answer 3

the myotome layer

Question 4

what is the muscular system composed of?

Answer 4

specialized cells

muscle fibers

Question 5

what form the extensor muscles of the vertebral column?

Answer 5

epimers- dorsal primary rami

Question 6

what gives rise to the muscles of the limbs and body walls?

Answer 6

hypomers- ventral primary rami

Question 7

what are examples of changes in muscle direction?

Answer 7

1 migration of muscle- latissimus dorsi
2 fusion of successive myotomes- rectus abdominus
3 longitudinal splitting of the myotome- sternohyoid
4 tangenital splitting- oblique and trans ab
5 degeneration of myotomes- tensor fascia lata

Question 8

what are the muscles of the cervical region?

Answer 8

prevertebrals
scalenes
trap
SCM
infrahyoid

Question 9

what are the muscles of thoracic region?

Answer 9

intercostals

transverse thoracics

Question 10

nerves innervating the segmental muscles are divided into?

Answer 10

dorsal primary and ventral primary rami

Question 11

what happens to nerves when muscles change direction?

Answer 11

the nerves remain and muscles maintain original innervation

Question 12

what is the job of the ribs?

Answer 12

ribs cause the muscles in the wall of thorax to maintain their segments

Question 13

what is the 1st brachial/pharyngeal arch?

Answer 13

muscles of mastication

Question 14

what is the 2nd brachial/pharyngeal arch?

Answer 14

facial muscles

Question 15

what is the 3rd brachial/pharyngeal arch?

Answer 15

stylo-pharyngeal muscle

Question 16

what is the 4th & 6th arch?

Answer 16

laryngeal, pharyngeal, palate muscles, SCM, trap

Question 17

what are the innervations of the arches?

Answer 17

1- trigeminal
2- facial
3- glossopharyngeal
4 & 6- vagus, hypoglossal

Question 18

smooth muscle is derived from?

Answer 18

splanchnic mesoderm

Question 19

smooth muscle of the iris is derived from?

Answer 19

neuroectoderm

Question 20

with muscles of the limbs, the mesenchyme develops into what 2 groups?

Answer 20

extensors- dorsal group

flexors- ventral group

Question 21

what are cardiac muscles derived from?

Answer 21

splanchnic mesoderm

Question 22

most muscle defects are?

Answer 22

unilateral

Question 23

what is the most common unilateral muscle defect?

Answer 23

pectoralis is most frequent

trap and SCM- next

Question 24

what is prune belly?

Answer 24

distended abdomen from aplasia of the abdominal musculature

Question 25

the abdominal muscles are always?

Answer 25

bilateral

Question 26

when the SCM is injured during development what develops?

Answer 26

torticollis

Question 27

what are some characteristics of torticollis?

Answer 27

affects both sides equally male and female autosomal dominant gene

Question 28

in congenital torticollis...

Answer 28

SCM becomes fibrous