Exam 4

Question 1

Myology

Answer 1

scientific study of muscles & their parts

Question 2

Generally speaking, 2 main units exist in the muscular system… what are they?

Answer 2

structural unit: muscle fiber or muscle cell

functional unit: motor unit

Question 3

Skeletal muscle fibers are comprised of 2 primary constituents

Answer 3

• sarcoplasm: muscle cytoplasm

- myofibrils: sarcomeres in series-contractile elements

Question 4

Gross muscles may be comprised of how many muscle fibers?

Answer 4

only a few or as many as 1 million

Question 5

Structural unit

Answer 5

muscle fiber/muscle cell

Question 6

Functional unit

Answer 6

motor unit

Question 7

All muscle fibers are supplied with nerves (innervated) by terminal branches of a single ___ ___ ___?

Answer 7

alpha efferent axon

Question 8

How many motor units are located in each gross muscle?

Answer 8

multiple

Question 9

What does it mean if a motor unit is recruited?

Answer 9

all fibers w/in it are concurrently contracting

Question 10

As force demands increase…

Answer 10

more motor units are recruited

Question 11

Muscles containing a small # of muscle fibers per motor unit are capable of smaller/larger gradations (degrees, stages) in force output?

Answer 11

smaller

Question 12

Sarcoplasm

Answer 12

~25% protein in a non-contractile configuration

~75% fluid

Question 13

Myofibrils

Answer 13

various protein filaments configured to enable the contractile process

-series of sarcomeres

Question 14

Main filaments involved in contractions

Answer 14

myosin & actin

Question 15

Smaller filaments loosely bound to actin when the myofibril is relaxed

Answer 15

troponin & tropomyosin

Question 16

Muscle fibers have how many nuclei?

Answer 16

multiple

multi-nucleated

Question 17

Muscle fibers have a cell wall called the…

Answer 17

sarcolemma

Question 18

Sarcolemmas have 3 major substructures:

Answer 18

• Transverse Tubules (T Tubules)
• Terminal Cisternae
• Sarcoplasmic Reticulum (SR)

Question 19

Transverse Tubules

Answer 19

• inlets w/in the sarcolemma that provide for neural input

- Run roughly perpendicular to sarcomere

Question 20

Terminal Cisternae

Answer 20

• Storage vesicles for calcium
• Located parallel & contiguous (share a border) to transverse tubules
• May be referred to as vesicles of the SR

Question 21

Sarcoplasmic Reticulum

Answer 21

• conduit for calcium

- oriented roughly parallel to the sarcomere

Question 22

Sarcomere

Answer 22

structural unit of the myofibril

Question 23

Sarcomere contains the contractile elements between each pair of ___?

Answer 23

Z-disks

Question 24

Z-disks are ___ ____?

Answer 24

connective tissue

Question 25

In a relaxed sarcomere you have the following...

Answer 25

I-band A-band H-zone M-line

Question 26

I-band

Answer 26

light zone

Question 27

A-band

Answer 27

dark zone

Question 28

H-zone

Answer 28

in middle of A-band

Question 29

M-line

Answer 29

in middle of H-zone

Question 30

Connective tissue found within each ___ ____ and at ___ ____ outside of it.

Answer 30

muscle fiber multiple levels

Question 31

Connects sarcomeres?

Answer 31

z line / z disc

Question 32

Endomysium surrounds...

Answer 32

surrounds muscle fibers

Question 33

Perimysium surrounds...

Answer 33

surrounds fascicles

Question 34

Epimysium/fascia surrounds...

Answer 34

surrounds whole muscle

Question 35

Tendon is...

Answer 35

coalescing (coming together of) of epimysium and fascia that connects muscle to bone

Question 36

2 main types of extracellular protein fiber that affect elasticity of musculo-tendinous unit

Answer 36

collagen & elastin

Question 37

Collagen

Answer 37

- fibrous insoluble protein - found within connective tissue in muscle, skin, bone, ligaments, & cartilage - stiffens tissue - greater than or equal to 20 isoforms exist

Question 38

Elastin

Answer 38

- stores mechanical energy | - albuminoid protein (yellow elastic tissue found in connective tissue)

Question 39

Connective tissue fill where?

Answer 39

spaces b/w organs & tissues in the body

Question 40

Connective tissue mainly comprised of

Answer 40

- tough protein fibers embedded in a polysaccaride gel (extracellular matrix) - mainly secreted by fibroblasts

Question 41

Parallel elastic components made up of...

Answer 41

- sarcolemma - endomysium - perimysium - epimysium

Question 42

Other tissues that affect elasticity of musculo-tendinous unit

Answer 42

- parallel elastic components | - series elastic components