Muscle Tissue

Question 1

epimysium

Answer 1

dense irregular CT that separates muscle from surrounding tissue and organs and is connected to deep fascia

Question 2

perimysium

Answer 2

divides muscle into series of internal compartments (fasicles)

Question 3

endomysium

Answer 3

surrounds each skeletal muscle fiber; binds each muscle to its neighbor. satellite cells lie between endomysium

Question 4

organization of skeletal muscle

Answer 4

skeletal muscle, fascicle, muscle fiber, myofibril, myofilaments

Question 5

muscle fibers

Answer 5

• called fibers because they’re long, run from origin to insertion, parallel to one another
• contains muscle cell/fiber contains myofibrils

Question 6

muscle fascicles

Answer 6

contain muscle cells/fibers, within the fascicle, all muscle fibers are parallel to one another, surrounding each muscle cell/fiber in the fascicle is endomysium made of reticular fibers

Question 7

myofibrils

Answer 7

-contain the thick (myosin) and thin filaments arranged into sarcomeres

Question 8

sarcomeres

Answer 8

Z-disc to Z-dic, parallel to each other and to the long axis of the muscle (origin to insertion)

Question 9

thin filaments

Answer 9

• attach to the Z-discs at the ends of the sarcomere

- composed of actin, troponin, and tropomyosin

Question 10

troponin

Answer 10

binds to calcium, myosin can then bind to actin (forms a cross-bridge)

Question 11

thick filaments

Answer 11

center of the sarcomere, composed of protein myosin, myosin head is what attaches to actin in the presence of calcium

Question 12

anatomy of a sarcomere

Answer 12

A band: entire length of thick filaments, stains darker

I band: region that only includes thin filaments, stains lighter

Question 13

sarcoplasmic reticulum

Answer 13

• storehouse for calcium, when a muscle cells has an electric signal this calcium is released
• increase in calcium is the sarcoplasm binds to troponin and allows for formation of cross-bridges

Question 14

sliding filament mechanism

Answer 14

• myosin binds to actin creating a cross-bridge between the two filaments
• myosin head rotates towards the center of the sarcomere (power stroke) the power stroke pulls the thin filaments towards the center of the sarcomere
• sarcomeres shorten (Z-discs move closer) and both the H-zone (only thick filaments) and the I-band decrease in size

Question 15

neural innervation

Answer 15

-somatic motor neurons release acetylcholine (ACH) onto muscle fibers

Question 16

acetylcholine

Answer 16

causes muscle cell to generate an electric signal (action potential) which causes the cell to release calcium and contract by the sliding filament mechanism

Question 17

neuromuscular junction

Answer 17

ACH released by the somatic motor neuron binds nicotinic receptors on the sarcolemma

Question 18

action potential

Answer 18

in response to ACH-nicotinic receptor binding leads to calcium release from the SR

Question 19

calcium release from SR

Answer 19

this calcium binds to troponin and allows for cross-bridges to form and the sliding filament mechanism to occur

Question 20

difference between muscle fiber types

Answer 20

vary in content of myoglobin, the speed at which they undergo the sliding filament mechanism, and how they produce ATP

Question 21

skeletal muscle fiber types

Answer 21

• slow oxidative fibers (type I)
• fast oxidative-glycolytic (type IIa)
• fast glycolytic (type IIb)

Question 22

muscular dystrophy

Answer 22

the protein dystrophin connects thin filaments of the sarcomere to the membrane and is thought to transmit tension generated by muscle contraction to the tendon

Question 23

muscle origin

Answer 23

proximal and they are stationary during muscle contraction

Question 24

insertion

Answer 24

distal and they move during contraction

Question 25

reverse muscle action

Answer 25

muscle’s origin moves towards the insertion

Question 26

muscle contraction

Answer 26

muscle fibers contract and shorten and pull on the tendons

Question 27

tendons (aponeuroses)

Answer 27

act like the lines (sheets) that transmit the forces generated by muscle contraction

Question 28

patella

Answer 28

functions like a pulley that changes the direction of a force

Question 29

organization of skeletal fibers

Answer 29

• longer the fibers in a muscle-greater the range of motion

- power of muscle depends on its cross-sectional area

Question 30

parallel muscle types

Answer 30

flat, fusiform, strap

Question 31

pennate muscles

Answer 31

-muscle with fascicles that attach obliquely to the tendon**generates the highest degree of force but sometimes a decrease in range of motion

Question 32

pennate muscle example

Answer 32

unipennate, bipennate, multipennate

Question 33

unipennate

Answer 33

fascicles on one side of tendon

Question 34

bipennate

Answer 34

fascicles on both sides of central tendon

Question 35

multipennate

Answer 35

fascicles at oblique angle from many directions to several tendons

Question 36

tendons in pennate muscles

Answer 36

• one or more tendons run through the body of the muscle

- multi-pennate muscels have versatility by using different portions of the muscle

Question 37

primary action

Answer 37

• prime mover or agonist
• synergist: assists the prime mover
• antagonist: action that opposes the agonist

Question 38

naming of skeletal muscles

Answer 38

shape, size, location, attachment, number of origins, orientation of fibers, action

Question 39

other functions of msucles

Answer 39

support for soft tissue, form sphincters and encircle openings