Muscle Histology

Question 1

What is the epimysium?

Answer 1

Dense connective tissue that surrounds the entire muscle; synonymous with the deep fascia

Question 2

What is the perimysium?

Answer 2

Connective tissue that surrounds a group of fibers to form a fascicle; conveys the large blood vessels and nerves into the muscle

Question 3

What is the endomysium?

Answer 3

Delicate connective tissue that surrounds individual muscle fibers

Question 4

How do you differentiate between type I and type II skeletal muscle fibers in a histological section?

Answer 4

Stain for ATPase; type II will stain brown, type I will remain mostly white

Question 5

Cards about organization of skeletal muscle

Answer 5

Cool

Question 6

Histological slide of type I/II

Answer 6

Will do

Question 7

What are the properties of type I skeletal muscle fibers?

Answer 7

Efficiency over long periods of time; used for postural maintenance or endurance exercise; high levels of myoglobin

Question 8

How do type I skeletal muscle fibers generate ATP?

Answer 8

Oxidative phosphorylation

Question 9

What is the difference in contraction speed between type I and type II skeletal muscle fibers?

Answer 9

Type I fibers have a low contraction speed, type II fibers have a high contraction speed

Question 10

What is the difference in innervation between type I and type II skeletal muscle fibers?

Answer 10

Type I fibers have large motor units (large numbers of fibers innervated by a single neuron), type II fibers have small motor units (small number of fibers innervated by a single neuron)

Question 11

What is the sarcolemma?

Answer 11

Plasma membrane of muscle cells

Question 12

What are the properties of the sarcolemma?

Answer 12

Numerous ion transport proteins and receptors; surrounded by a basal lamina

Question 13

What is the transverse tubule system (T-tubules)?

Answer 13

A network formed by finger-like projections from the sarcolemma that make contact with the sarcoplasmic reticulum and transmit the depolarization signal deep into the muscle cell

Question 14

What is the sarcoplasmic reticulum (SR)?

Answer 14

Internal membrane network that makes junctional complexes with T-tubules (triads); site of intracellular Ca²⁺ storage and release

Question 15

What two filaments are myofibrils composed of?

Answer 15

Actin and myosin

Question 16

What is the function of desmin?

Answer 16

Anchors to the inside of the sarcolemma and extends between myofibrils to help organize the cytoplasm and facilitate coordinated contraction

Question 17

What connective tissue layer is represented by 3?

Answer 17

Endomysium

Question 18

What connective tissue layer is represented by 2?

Answer 18

Perimysium

Question 19

What connective tissue layer is represented by 1?

Answer 19

Epimysium

Question 20

What structure is represented by 9?

Answer 20

Fascicle

Question 21

What structure is represented by 8?

Answer 21

Muscle cell or myofiber

Question 22

What structure is represented by 10?

Answer 22

Total muscle

Question 23

What is 1?

Answer 23

Sarcomere

Question 24

What is 2 and what are its properties?

Answer 24

Z line; define the boundaries of each sarcomere; contains α actinin (actin binding protein)

Question 25

What is 3 and what are its properties?

Answer 25

I band; composed exclusively of actin thin filaments; width decreases during contraction

Question 26

What is 4 and what are its properties?

Answer 26

M line; middle of H band; overlapping tails of thick filaments

Question 27

What is 5 and what are its properties?

Answer 27

H band; central region of the A band that contains only thick filaments; width decreases during contraction

Question 28

What is 6 and what are its properties?

Answer 28

A band; composed of overlapping thick and thin filaments; width decrease during contraction

Question 29

Which cells are type I skeletal muscle cells? Which are type II?

Answer 29

Type I are mostly white; type II are brown

Question 30

What are the components of the troponin complex?

Answer 30

Troponin-I, troponin-T, troponin-C

Question 31

What is the function of troponin-I?

Answer 31

Inhibits the binding of myosin to actin

Question 32

What is the function of troponin-C?

Answer 32

Binds Ca²⁺

Question 33

What is the function of troponin-T?

Answer 33

Binds tropomyosin

Question 34

What is the composition of thin filaments?

Answer 34

A twisted, double stranded F-actin filament composed of G-actin monomers; nebulin (stabilizer of thin filament length)

Question 35

What does F-actin complex with?

Answer 35

Tropomyosin and the troponin complex

Question 36

What is the composition of thick filaments?

Answer 36

Myosin (two identical heavy chains and two pair of light chains); titin (controls assembly, provides elasticity)

Question 37

What are the properties of the globular head of the myosin heavy chain?

Answer 37

Contains a binding site for actin; ATPase domain facilitates the hydrolysis of ATP; activity regulated by the myosin light chains

Question 38

Not really sure how to make cards for the sliding filament model so have fun with that

Answer 38

...thanks