Muscle Notes

Front 1

Muscle tissue makes up _______% of the total body weight.

Back 1

40-50%

Front 2

How many muscles are there in the body?

Back 2

Over 600

Front 3

Myology

Back 3

The study of muscles

Front 4

All muscle cells are ________, therefore called muscle fibers.

Back 4

Elongated

Front 5

Smooth Muscle

Back 5

- involuntary

- found in hollow organs

- slow contraction

Front 6

Skeletal Muscle

Back 6

- can contract rapidly

- tires easily, must rest

- tremendous power

Front 7

Cardiac Muscle

Back 7

- contracts steadily

- found in heart only!

- can increase for brief periods of time if needed

Front 8

Endomysium

Back 8

Connective tissue that wraps around each individual muscle fiber

Front 9

Fascicles

Back 9

Bundles of individual muscle fibers

Front 10

Perimysium

Back 10

Connective tissue that wraps around each fascicle

Front 11

Tendons

Back 11

Anchor muscles to bones, continuous with the periosteum to the bone

Front 12

Marbling

Back 12

Fat between the muscle bundles

Front 13

Fascia

Back 13

- fibrous connective layer

- found in superficial and deep layers

Front 14

Superficial Fascia Function

Back 14

- thermal regulator (fat)

- protection (from bony prominences)

- energy source

Front 15

Deep Fascia

Back 15

- organized connective tissue layer composed of dense irregular connective tissue

- covers muscles

- form tendon sheaths

Front 16

Continuous throughout the whole body

Back 16

Superficial and Deep Fascia

Front 17

Belly

Back 17

Fleshy part of muscle between origin and insertion

Front 18

Origin

Back 18

Least movable end; 'fixed' end

Front 19

Insertion

Back 19

More movable end; stronger portion of the two

Front 20

Types of Muscle Attachments

Back 20

Direct, Indirect

Front 21

Indirect Attachments

Back 21

Muscle connective tissue extend to form a tendon or aponeurosis (sheet)

- tendon attaches to periosteum, preichondrium or fascia

- tendon is most common

Front 22

Prime Movers / Agonists

Back 22

Bears the major responsibility for producing movement

Front 23

Antagonists

Back 23

Act to reverse or act against the action of the agonist

Front 24

Synergists

Back 24

Compliments the prime mover; assists another muscle

Front 25

Fixators

Back 25

Holds parts of the body in proper position for the actions of other muscles

Front 26

Skeletal Muscle funtion

Back 26

- movement

- heat production

- posture

Front 27

Characteristics of Muscle

Back 27

Excitability - stimulate

Contractility - shorten

Extensibility - stretch

Front 28

Muscle fibers use large amounts of energy to contract, therefore need ______ and ______.

Back 28

O2 and Nutrients (glucose)

Front 29

Muscle Capillaries

Back 29

Long and winding to accomodate changes in muscle length

Front 30

Nerve impulses from somatic motor neurons cause muscle fibers to _______

Back 30

Contract

Front 31

One motor neuron can innervate ____________ or ___________ of muscle fibers.

Back 31

A few, thousands

Front 32

Precision Movements

Back 32

Fewer fibers in motor unit

Front 33

Large Movements

Back 33

1 neuron supplying hundreds to thousands of muscle fibers

Front 34

Myofibril

Back 34

bundle of myofilaments found in the organelles of muscle fiber that contracts

Front 35

Myofilaments

Back 35

Tropomyosin, actin, and myosin filaments that cause contractions

- arranged into sacromeres

Front 36

Myosin

Back 36

Thick filament (two wrapped up golf clubs)

- attach to the cross bridge sites

Front 37

Actin

Back 37

Thin filament (twisted pearl necklace)

- active site for myosin to attach

Front 38

Tropomyosin

Back 38

Part of thin filament (thin string wrapped around actin)

- covers up the active sites

Front 39

Troponin

Back 39

- globular protein

- composed of 3 subunits that binds with actin, tropomyosin or calcium

- part of thin filament

Front 40

Mitochondria

Back 40

Organelle in muscle fiber that makes ATP

Front 41

T- Tubule

Back 41

Transverse tubule that extends from the sacrolemma to the muscle fiber

- conveys impulses for Ca to be released from sarcoplasmic reticulum

Front 42

Sarcoplasmic Reticulum

Back 42

Smooth ER of a muscle fiber

- stores Ca

Front 43

Triad

Back 43

One T-Tubule and 2 adjacent sarcoplasmic reticulum

Front 44

Sarcoplasm

Back 44

Cytoplasm of a muscle fiber

Front 45

Glycogen

Back 45

Polysaccharide that stores energy for muscle contraction

Front 46

Myoglobin

Back 46

Red pigment that stores O2 for muscle contraction

Front 47

ACh (Acetylchlorine)

Back 47

Neurotransmitter released by nerve cells at the neuromuscular junction

Front 48

Z Disc

Back 48

Dense plate to which actin filaments attach

Front 49

A Band

Back 49

Runs the entire length of the myosin filament

Front 50

I Band

Back 50

Includes the Z Discs and actin filaments where they do not overlap myosin

Front 51

H Zone

Back 51

Middle region of myosin where actin does not overlap it

Front 52

M Line

Back 52

Protein filaments running transversely through the middle of the myosin filaments, holding them in place

Front 53

Muscle Contraction

Back 53

Learn on your own, last 2 pages of L7B