Lecture 12

Question 1

Muscular system:
-___% body mass
-large blood supply
-through all the body
-3 types:

Answer 1

50%
skeletal
cardiac
smooth

Question 2

__________ muscles (muscles attached to skeleton) = _________ muscles (under our conscious control) = ________ muscles (looks striped)

Answer 2

skeletal; voluntary; striated

Question 3

5 functions of muscles
1.
2.
3.
4.
5.

Answer 3

1. movement (body and body contents: breathing circulation, digestion) (communication through speech, writing, nonverbal)
2. stability
3. control of openings and passageways (sphincters)
4. Heat production
5. Glycemic control (glucose storage)

Question 4

Muscle compartment
-intermuscular septa:

Answer 4

very thick fascia that separate one compartment from another

Question 5

Fascia

Answer 5

made up of sheets of connective tissue that is found below the skin
-can be classified as superficial, deep, visceral, or partial

Question 6

Epimysium

Answer 6

fibrous sheath surrounding entire skeletal muscle (deep fascia)

Question 7

perimysium

Answer 7

wrapped around muscle fascicles
-thicker layer that contains nerves, blood vessels, and stretch receptors (muscle spindles)

Question 8

Muscle fascicle

Answer 8

bundle of muscle fibers

Question 9

Endomysium

Answer 9

thin sleeve of loos connective tissue around EACH muscle fiber
-allows room for capillaries & nerve fibers
-provides chemical environment for the cell

Question 10

strength of muscle and direction of its pull are determined partly by the _________ of its _______
- the skeletal muscles of the body typically come in ___ different shapes

Answer 10

-orientation; fascicles
-7

Question 11

7 shapes of muscles

Answer 11

Fusiform
Parallel
Triangular
Circular
Unipennate
Bipennate
Multipennate

Question 12

Fusiform shape of muscle:
-______ in the middle and _______ at each end
-relatively _______
ex:

Answer 12

-thick; tapered
-strong
-biceps brachii

Question 13

Parallel shape of muscle:
-uniform width
-parallel fascicles to the long axis of the muscle
-produce _____ force
-the _______ in body
ex:

Answer 13

-less
-majority
-rectus abdominis

Question 14

Triangular (convergent) shape of muscle:
-______ at 1 end and narrow at the other
-relatively _______
ex:

Answer 14

-broad
-strong
-pectoralis major

Question 15

Circular (sphincter) shape of muscle:
-forms _____ around body openings
ex:

Answer 15

-rings
-orbicularis oculi

Question 16

Unipennate, Bipennate, and Multipennate shape of muscles:

Unipennate:
-fascicles approach tendon from ______
ex:

Bipennate:
-fascicles approach tendon from _____
-shaft like in feather
ex:

Multipennate:
-bunches of feathers converge at ______
ex:

the STRONGEST muscle shape

Answer 16

-one side
ex: palmar interosseous

-both sides
ex: rectus femoris

-single point
ex: deltoid

Question 17

Skeletal muscles usually work as __________ pairs to produce the movement

Answer 17

antagonistic

Question 18

Movement in a DIRECT manner

Answer 18

little separation between muscle and bone

Question 19

Movement in an INDIRECT manner

Answer 19

-tendon
-aponeurosis

Question 20

Tendon:
-cord like, fibrous connective tissue (_____________)
-mainly consists of _______ fibers running parallel to the force generated by the muscle to which they are attached
-also contains ______ proteins, which improve the tendons’ elasticity
-attaches _______ to _______
-_________ tendon is the thickest and strongest tendon in the body
-_________: connective tissue band that covers the tendons from a group. of muscles and helps hold them in place

Answer 20

-dense regular
-collagen
-elastic
-muscle; bone
-achilles
-retinaculum

Question 21

Aponeurosis:
-large, ______ -like layers of connective tissue with a similar composition to tendons
-provides structure and distributes tension across wider area or large number of muscle groups
-can also connect _______ to adjacent _______
-can attach muscles to the ________
-allows bones of the _____ to bear all weight of the body

Answer 21

-sheet
-muscles; muscles
-facial dermis
-feet

Question 22

there are also skeletal muscles that do not pull against skeleton for movements, for example the muscles that produce __________

Answer 22

facial expressions (they are in contact with the skin)

Question 23

the muscle that provides the major force to complete the movement

Answer 23

agonist (prime mover)

Question 24

muscle that opposes the action of the prime mover (relaxes or contracts)

Answer 24

antagonist

Question 25

muscle that prevents movement of bone while prime movers act

Answer 25

fixator

Question 26

muscle that aids the prime mover
-may contribute to additional force
-modify the direction of movement
-stabilize a nearby joint

Answer 26

synergist

Question 27

Universal characteristics of muscle
1.
2.
3.
4.
5.

Answer 27

1. Excitability
2. Conductivity
3. Contractility
4. Extensibility
5. Elasticity

Question 28

Excitability

Answer 28

-responsiveness (to chemical signals, stretch)
-ability to respond to a stimulus

Question 29

Conductivity

Answer 29

local electrical excitation sets off a wave of excitation that travels along the muscle fiber

Question 30

Contractility

Answer 30

muscle shortens when stimulated

Question 31

Extensibility

Answer 31

capable of being stretched between contractions

Question 32

Elasticity

Answer 32

returns to its original rest length after being stretched

Question 33

single muscle fibers are formed from the fusion of embryonic __________ cells. Each retains its nucleus during fusion

Answer 33

myoblasts

Question 34

__________ cells (muscle stem cells) are involved in the muscle regeneration following injury or disease

Answer 34

satellite

Question 35

Inside of each muscle fiber:

sarcolemma

Answer 35

plasma membrane of a muscle fiber

Question 36

Inside of each muscle fiber:

sarcoplasmic reticulum

Answer 36

smooth ER that forms a network of tubular canals and sacs around each myofibril

-acts as a Ca2+ reservoir (for contraction)

Question 37

Inside of each muscle fiber:

T tubules

Answer 37

deep invaginations of the sarcolemma

-run between each pair of terminal cisternae

-conduct each impulse to the deepest regions of the muscle fiber

Question 38

Inside each muscle fiber:

Triad

Answer 38

the complex of the T tubule flanked by 2 terminal cisterns

Question 39

Inside each muscle fiber:

Myofibril

Answer 39

rodlike contractile organelles
-occupy most of sarcoplasm
-composed of sarcomeres arranged end-to-end

Question 40

-striations are alternating ________(dark) and ________ (light)

-striations result form the precise organizations of ______ (thick) and ______ (thin) in cardiac and skeletal muscle cells

Answer 40

A-bands; I-bands
-myosin; actin

Question 41

sarcomere=

Answer 41

segment from Z disc to Z disc

Question 42

Connectin (elastic filament, Titin)
-giant, springy protein
-interconnects thick filament with ________
-helps stabilize and position thick filament
-prevents _________ and provides _________

Answer 42

-Z disc
-overstretching; recoil

Question 43

Thick filaments
contains:
-double gobbler heads
-top of heads are _____ binding sites
-bottoms of heads are ______ binding site

Answer 43

actin; ATP

Question 44

Thin filaments
-troponin:
-tropomyosin:
-string of _______________ subunits each with an active site that can bind to head of _______ molecules

Answer 44

-Ca-binding protein on each tropomyosin molecule
-Each blocking 6-7 active binding sites on G actin subunits
-globular (G) actin; myosin

Question 45

Several other proteins associate with myofilaments to anchor, align, and regulate them

dystrophin

Answer 45

links actin in outermost myofilaments to membrane proteins that link to endomysium

Question 46

Genetic defects in _______ produce disability disease _____________

Answer 46

Dystrophin; muscular dystrophy