Muscle Structure

Question 1

Types of Muscle

Answer 1

Skeletal
Smooth
Cardiac

Question 2

Properties of muscles

Answer 2

Contractility
Excitability
Extensibility
Elasticity

Question 3

Contractility

Answer 3

Ability to shorten muscles

Question 4

Excitability

Answer 4

Capacity for muscles to receive and respond to stimuli

Question 5

Extensibility

Answer 5

Ability for muscles to be stretched

Question 6

Elasticity

Answer 6

Ability to return to original shape after contraction

Question 7

Cardiac Muscle

Answer 7

Branching, striated, generally uninucleated cells that interdigitate at specialized junctions (intercalated discs)

Function: As it contracts, it propels blood into the circulation

Involuntary control

Question 8

Smooth Muscle

Answer 8

Spindle-shaped cells with central nuclei ; cells arranged closely to form sheets; no striations

Function: Propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control

Location: mostly in walls of hallow organs

Question 9

Skeletal Muscle

Answer 9

Long, cylindrical, multinucleate cells; obvious striations

Function: Voluntary movement; locomotion;manipulation of the environment; facial expression; voluntary control

Location: In skeletal muscles attached to bones or occasionally to skin

Question 10

Parts of skeletal muscle

Answer 10

Muscle fiber–> endomysium–>perimysium–> epimysium

Question 11

Muscle fiber

Answer 11

Each muscle fiber has myofibrils and filaments

Question 12

Myofibril

Answer 12

the contractile unit that consists of thick (myosin) and thin (actin) filaments

Question 13

Sarcolemma

Answer 13

The plasma membrane of the muscle cell

Question 14

Sarcoplasm

Answer 14

The cytoplasm of striated muscle cells.
Critical for maintaining ion and pH balance

Question 15

Sarcomere

Answer 15

Made of proteins
A band
I band
H band
Z line

Question 16

When the sarcomere is relaxed

Answer 16

both I and A band are at normal length
When relaxed, the troponin complex covers the myosin binding site

Question 17

When the sarcomere is partially contracted

Answer 17

The I band is starting to shorten

Question 18

When the sarcomere is fully contracted

Answer 18

The I band is shortened completely
The A band is stretched

Question 19

Thick Myofilaments

Answer 19

Closer to center of sarcomere. Made of myosin

Question 20

Thin Myofilaments

Answer 20

Runs parallel to the long axis of the sarcomere. Made of actin

Has tropomyosin and myosin binding site

Question 21

Resting Sarcomere

Answer 21

The myosin is not attached to the binding sites of actin

Question 22

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