Muscular System

Question 1

long, cylindrical multinucleated cells

voluntary control

Answer 1

skeletal muscle

Question 2

found in heart

involuntary control

striated

Answer 2

cardiac muscle

Question 3

involuntary control

found in hollow viscera, skin, and iris

Answer 3

smooth muscle

Question 4

all muscles develop from ______

except ____ which is from ________

Answer 4

mesoderm

iris, neuroectoderm

Question 5

trunk muscles develop from

Answer 5

myotome region of somites; mesenchyme differentiates to myoblasts

Question 6

limb muscles develop from

Answer 6

myogenic precursor cells in developing limb buds differentiate to myoblasts

Question 7

define myogenesis

Answer 7

elongation of nuclei and cell bodies into myoblasts

Question 8

contractile elements of the muscle fiber

Answer 8

myofilaments

Question 9

in skeletal muscle development, primordial muscle cells fuse end to end to form _____

Answer 9

myotubes

Question 10

mature myoblasts that are long and multinucleated

Answer 10

myocytes or myofibers

Question 11

in skeletal muscle development, the myotome divides into (2)

Answer 11

epaxial division (dorsal)

hypaxial division (ventral)

Question 12

epaxial division of myotome contains (2)

Answer 12

segmental muscles of body axis

extensor muscles of neck and vertebral column

Question 13

hypaxial division of myotome contains (4)

Answer 13

cervical muscles
thoracic muscles
lumbar muscles
limbs, intercostal, and abdominals

Question 14

in skeletal muscle development, myoblasts divide into (3)

Answer 14

pharyngeal arch muscles (facial expression)

tongue muscles

ocular muscles

Question 15

somite myotomes become segmented, then

Answer 15

myoblasts of each segment give rise to different adult muscles

Question 16

what are satellite cells

Answer 16

muscle stem cells

Question 17

all fibrous CT investments in muscle are interconnected and form _______ and________

Answer 17

tendons and aponeuroses

Question 18

Basal lamina surrounds _______

Endomysium surrounds _______

perimysium surrounds _______

Epimysium surrounds _______

Answer 18

a single myocyte

a singly myocyte

a fascicle of myocytes

a named muscle

Question 19

what makes up a motor unit

Answer 19

1 motor neuron + all innervated muscle fibers

Question 20

oxygen-transporting protein in myocytes

Answer 20

myoglobin

Question 21

type of muscle fiber with more myoglobin, more mitochondria, aerobic, uses fat

endurance

Answer 21

Type 1 (red)

Question 22

type of muscle fiber with less myoglobin, fewer mitochondria, anaerobic, uses glycogen

stronger but less endurance

Answer 22

Type 2A (white)

Question 23

where can satellite cells be found?

Answer 23

adjacent to myocytes, inside basal lamina

Question 24

myocyte plasma membrane

Answer 24

sarcolemma

Question 25

invagination of sarcolemma specialized for depolarization

Answer 25

T-tubules

Question 26

ER of muscle fibers

Answer 26

sarcoplasmic reticulum

Question 27

what does the SR do?

Answer 27

stores Ca+, forms terminal cisternae (triad with T-tubule), regulates muscle contraction through controlled release and sequestering of Ca+

Question 28

myocyte cytoplasm extends from Z disk to Z disk

Answer 28

sarcoplasm

Question 29

basic contractile unit of the the myocyte; composed of myofilaments

Answer 29

sarcomere

Question 30

two types of myofilaments found in a sarcomere, and where they're anchored

Answer 30

``` Myosin II (thick) - anchored at M line ``` Actin (thin) - anchored at Z disk

Question 31

How are actin filaments Ca regulated?

Answer 31

they are decorated with troponin and tropomyosin

Question 32

linear string of sarcomeres that runs the length of the myocyte

Answer 32

myofibril

Question 33

what's the A band

Answer 33

where the muscle contracts to (on each side)

Question 34

what is found at the myoneural junction?

Answer 34

axon terminals motor end plate

Question 35

specialized section of sarcolemma with Ach receptors

Answer 35

motor end plate

Question 36

what do the sensory nerves that innervate skeletal muscle do? (2)

Answer 36

provide feedback for spinal reflexes and regulation of contraction/relaxation

Question 37

specialized group of myocytes associated with sensory nerves to monitor stretching

Answer 37

muscle spindles

Question 38

group of collagen fibers associated with sensory nerves to monitor force of contraction

Answer 38

Golgi tendon organs

Question 39

cardiac muscle forms from ______ _______ mesoderm, aka _________

Answer 39

lateral splanchnic myoepicardial mantle

Question 40

how are intercalated discs formed

Answer 40

myoblasts fuse together, but cell membranes don't regress

Question 41

half of cell volume of cardiac muscle is (2)

Answer 41

mitochondria and myoglobin

Question 42

smooth muscle is regulated by

Answer 42

ANS

Question 43

Describe the role of dense bodies in contraction of smooth muscle

Answer 43

dense bodies form unions of intermediate filaments and thin filaments in interconnecting branching network that extends throughout cytoplasm contraction all filaments to twist and shorten cell along it's longitudinal axis

Question 44

sternocleidomastoid injured at birth, so muscle is shortened on one side

Answer 44

congenital torticollis

Question 45

when do limb buds appear?

Answer 45

end of 4th week

Question 46

in limb formation, mesenchyme proliferates near posterior margin of limb bud and forms ___________

Answer 46

zone of polarizing activity (ZPA)

Question 47

ectoderm near limb bud apex forms ________

Answer 47

apical ectodermal ridge (AER)

Question 48

AER activates ZPA to express _________

Answer 48

sonic hedgehog gene

Question 49

Five key steps in limb formation

Answer 49

limb bud hand plate digital rays finger/toe buds apoptosis of webbing

Question 50

in week 7, upper limbs rotate ______ 90 degrees lower limbs rotate _______ 90 degress

Answer 50

laterally medially

Question 51

area of skin supplied by a spinal nerve

Answer 51

dermatome