Muscle Tissue

Question 1

Characteristics & Functions of Skeletal Muscle

Answer 1

Moves the skeleton; Under voluntary control; Multinucleated, long cylindrical fibers, striated

Question 2

Characteristics & Functions of Cardiac Muscle

Answer 2

Only found in heart wall; involuntary control; striated

Question 3

Characteristics & Functions of Smooth Muscle

Answer 3

Found in walls of hollow organs; involuntary control; no striations

Question 4

What are the properties of Muscle Tissue?

Answer 4

Excitability, Extensibility, Contractility, Elasticity

Question 5

What is excitability?

Answer 5

Property of muscle tissue where nerve signal excites the muscle, causing contraction

Question 6

What is contractility?

Answer 6

A property of muscle that states when a muscle contracts, it shortens

Question 7

What is extensibility?

Answer 7

A property of muscle that allows for the muscle to go back to resting length after contraction

Question 8

What is Elasticity?

Answer 8

A property of muscle that allows a muscle to passively recoil and resume resting length after being stretched

Question 9

What are the subunits of a whole muscle?

Answer 9

Fascicles

Question 10

What are fascicles made of?

Answer 10

Muscle Fibers

Question 11

What are the CT of muscles? Where are they found and what are they made of?

Answer 11

Epimysium: surrounds whole muscle (dense IR)
Perimysium: surrounds fascicles (Fibrous CT)
Endomysium: surrounds individual muscle fibers (Loose CT)

Question 12

What are individual muscle fibers made of?

Answer 12

Myofibrils

Question 13

What are the repeating units that make up a myofibril?

Answer 13

Sacromeres

Question 14

What are the proteins that make up a sarcomere?

Answer 14

Myofilaments

Question 15

What are the types of Myofilaments? And what are they made of?

Answer 15

Thick filament: myosin
Thin filament: Actin, Tropomyosin, Troponin
Elastic filament: Titin

Question 16

Draw and Label the Parts of a sarcomere

Answer 16

I bands, A bands, H zones, M line

Question 17

During contraction, how do the striations of the sarcomere change?

Answer 17

I bands shorten, A bands remain the same, H zones disappear, Z discs remain the same

Question 18

What are T tubules?

Answer 18

Extensions of the sarcolemma that extend into muscle fiber; wrap around myofibrils; carry electrical stimulus to myofibrils

Question 19

What does the sarcoplasmic reticulum do?

Answer 19

Stores and releases calcium ions

Question 20

What is the Sliding Filament Theory?

Answer 20

During a contraction, actin and myosin filaments slide over each other

Question 21

What is a motor unit?

Answer 21

1 motor neuron and all the muscle fibers it innervates

Question 22

Motor units with more muscle fibers per motor unit are better for…

Answer 22

… powerful contractions

Question 23

What is the neuromuscular junction?

Answer 23

Where motor neuron meets muscle fiber; stimulation of muscle fiber can occur

Question 24

Characteristics & Functions of Parallel Muscles

Answer 24

Fascicles run parallel to axis of muscle; Tendon on either end; Longer fibers, can shorten more

Question 25

Characteristics & Functions of Pennate Muscles

Answer 25

Tendon runs whole length of muscle; Allows for more fibers, stronger

Question 26

Characteristics & Functions of Convergent Muscles

Answer 26

Fascicles converge into tendon at insertion

Question 27

Characteristics & Functions of Circular Muscles

Answer 27

Fascicles arranged in a ring; Sphincter muscles

Question 28

What are the different muscle attachments?

Answer 28

Origin: attachment site that is not moved during contraction Insertion: attachment site that is moved when muscle shortens

Question 29

What is a direct muscle attachment?

Answer 29

Short, dense regular CT fibers connect muscle to bone

Question 30

What is an indirect muscle attachment?

Answer 30

Long, dense regular Ct fibers connect muscle to bone

Question 31

What is a synergist?

Answer 31

Muscles that work together to perform an action

Question 32

What is an antagonist?

Answer 32

Muscles that perform opposite functions

Question 33

What is a prime mover/agonist?

Answer 33

Muscle that is primarily responsible for a movement

Question 34

What is a fixator?

Answer 34

A synergist that assists by holding a bone firmly in place to allow the prime mover to work more effectively

Question 35

What causes an increase in muscle strength and size?

Answer 35

With injury, satellite cells (immature cells) fuse with muscle fibers and proliferate. New satellite cells produce proteins that help repair the damaged muscle fibers

Question 36

What type of cellular junction allows cardiac muscle cells to contract in a coordinated fashion?

Answer 36

Gap Junction

Question 37

What are the 2 layers of smooth muscle? Where are they found?

Answer 37

Circular layer: closest to lumen of organ | Longitudinal layer: wraps around circular layer