Muscle Structure & Function

Question 1

Muscular Connective Tissue @ Macrostructure Level Sarcolema

Answer 1

thin, transparent membrane covering muscle fibers

Question 2

Muscular Connective Tissue @ Macrostructure Level Endomysium

Answer 2

connective tissue covering sarcolemma/muscle fibers *inner most

Question 3

Muscular Connective Tissue @ Macrostructure Level Perimysium

Answer 3

connective tissue covering groups of muscle fibers *middle

Question 4

Muscular Connective Tissue @ Macrostructure Level epimysium

Answer 4

endomysium and perimysium are continues with epimysium *outermost

Question 5

Muscular Connective Tissue @ Macrostructure Level myofilaments

Answer 5

actin and myosin

Question 6

Muscle>muscle fascicles>muscle fiber> myofibril>myofilaments

Answer 6

all of these blend to form connective tendon sheath at myotendinous junction

Question 7

SR (Sarcoplasmic reticulum) T-Tubule (transverse tubules)

Answer 7

storage site for calcium T-tubule: connectors of all fibers

Question 8

Sarcomere

Answer 8

thick and thin alternations form distinctive striped pattern Z to Z

Question 9

myosin

Answer 9

Thick filaments

Question 10

actin

Answer 10

thin filaments

Question 11

titin

Answer 11

links myosin to Z line

Question 12

A Band portion

I-Band

Answer 12

portion that extends over both lenght of thick and small portion of thin filament

(myosin & actin)

Iband ( only thin)

hzone- no overlapping

Question 13

What is attached to actin

Question 14

Myosin

Answer 14

Globular enlargments call head groups for binding sites for acti that swivel, responsible for power stroke of head, splits ATP

Question 15

Sliding filament Theory

Answer 15

myosin turns ATP to ADP and Pi, this energizes head

to be continued

Question 16

Tropomysosin

Troponin

Answer 16

regulatory protein that blocks myosin binding site on actin

Troponin- represents switch that binds calcium and blocks neutralizes tropomyosin

Question 17

Motor Unit Structure

Efferent

Answer 17

A in

E Out

Starts at anterior horn, goes through axon to motor endplats at each muscle fiber

Question 18

Type I Oxidative Efferent

Question 19

Type IIB glycolytic of efferent neuron

Answer 19

large diameter, white, sparse capillary supply, fast contraction speed, fast fatigue rate,

So generate greater force but fatigue quickly

Question 20

AP (action potential) causes release of what in NMJ

Answer 20

acetylcholine

Question 21

Agonist (prime mover

Question 22

Antagonist Muscles

Answer 22

opposite effect of agonist

permits joint action by shortening or passively elongating

Question 24

Fixers/ Stabilizers are supporters

Question 25

Neutralizer

Answer 25

Contracts to prevent undesired movemtns of one of the prime movers

ex. is 3 different tendons of hamstrings

Question 26

Shunt & Spurt

Answer 26

shunt: muscle with proximal attachment close to joint axis and distal attachment is far away. This maintians joint stability. *better compression

Spurt: muscle with proximal attachment far from joint axis

Question 27

What is a first, second, and third degree lever?

Answer 27

A Type 1 Lever is where the pivot (fulcrum) is between the effort and the load. In an off-center type one lever (like a pliers), the load is larger than the effort, but is moved through a smaller distance. i.e. a hammer

A Type 2 Lever is where the load is between the pivot (fulcrum) and the effort. i.e. a wheelbarrow

A Type 3 Lever is where the effort is between the pivot (fulcrum) and the load. i.e. tweezers

Question 28

active insufficiency

Answer 28

diminished ability to produce tension when a muscle is placed in an overly shortened or lenghtenened position

fingers griped

Question 29

passive insufficiency

Answer 29

insufficient lenght to permit completion of ROM available at the joints crossed by the passive muscle

fingers loose

Question 30

torque

Answer 30

force X displacement vector

Question 31

concentric contraction

Answer 31

shortening contraction

internal load ovecomes external load

Question 32

Eccentric contraction

Question 33

isometric contraction

Answer 33

internal shortening, no external change in lenght