Microscopic anatomy and organization of skeletal muscle

Question 1

-comprises most of muscle tissue in body
-attaches to skeleton or associated connective tissue
-provides shape, structure, and ability to move

Answer 1

skeletal muscle

Question 2

2 parts to muscle fibers causing striated appearance

Answer 2

• dark A band
  -light I band

Question 3

muscle fibers for skeletal are

Answer 3

long, large, cylindrical cells

Question 4

long, rod shaped organelles which fill sacroplasm

Answer 4

microfibrils

Question 5

cytoplasm of muscle tissue

Answer 5

sacroplasm

Question 6

the plasma membrane surrounding 1 muscle fiber and contains many myofibrils

Answer 6

sacrolemma

Question 7

myofibrils are made up of even smaller threadlike structures called

Answer 7

myofilaments

Question 8

contractile proteins slide past each other during muscle activity to allow for muscle contraction

Answer 8

-actin
-myosin

Question 9

-contractile unit of muscle
-extend from middle of one I band (z disc) to middle of next I band on myofibril

Answer 9

sacromeres

Question 10

isotropic bands
-light band; contain only thin (actin) filaments

Answer 10

I band

Question 11

anisotropic bands
-dark band; contains entire length of simple thick (myosin) filament

Answer 11

A band

Question 12

zone of thick (myosin) filaments that contains no thin (actin) filaments

Answer 12

H zone

Question 13

direct center (middle) of sacromere; accessory proteins link thick (myosin) filaments

Answer 13

M line

Question 14

the junction between I and A bands where sacrolemma indents into muscle cell

Answer 14

transverse tubule (T tubule)

Question 15

run deep into muscle fiber between terminal cisterns of elaborate smooth ER

Answer 15

t tubules

Question 16

-region where t tubule and SR terminal cistern converge
-point where an electrical signal moves from sarcolemma to SR to drive muscle contraction

Answer 16

triads

Question 17

areolar connective tissue sheath, enclosing each muscle fiber

Answer 17

endomysium

Question 18

several sheathed muscle fibers bound together in a bundle by a collagenic membrane

Answer 18

fascicle (perimysium)

Question 20

many fascicles are bound together and surrounded by dense connective tissue

Answer 20

epimysium

Question 21

must stimulate voluntary skeletal muscles via nerve impulses

Answer 21

motor neurons

Question 21

junction between an axon of a motor neuron and a muscle fiber

Answer 21

NMJ

Question 21

-bind muscle fibers; provide 2 major functions:
1) durability
2) space conservation (relatively small size
)

Answer 21

tendons

Question 22

neuron and stimulated muscle fiber, separated by a synaptic cleft

Answer 22

motor unit

Question 23

binds w/ receptors on sarcolemma, causing depolarization and contraction of muscle

Answer 23

Ach