Muscle Tissue And Organization Ch. 10

Front 1

Three types of muscles in the body:

Back 1

Skeletal
Cardiac
Smooth

Front 2

A skeletal muscle is...

Back 2

an organ
*constructed of all four tissue types

Front 3

Number of skeletal Muscles

Back 3

Over 700
o Together they form the muscular system

Front 4

Four unique characteristics of muscle tissue:

Back 4

excitability
contractability
extensibility
elasticity

Front 5

excitability

Back 5

electrical changes in muscle fiber (cell)

Front 6

contractability

Back 6

– shortening of muscle fiber

Front 7

extensibility

Back 7

can be stretched beyond relaxed length

Front 8

elasticity

Back 8

return to original length when tension is released

Front 9

5 Functions of Skeletal Muscle Tissue

Back 9

1. Body Movement
2. Maintenance of posture .
3. Temperature regulation
4. Storage and movement of materials
5. Support

Front 10

Muscle comprised of muscle

Back 10

fibers

Front 11

Muscle fibers organized into bundles called...

Back 11

Fascicles

Front 12

Fibers contain...

Back 12

myofibrils

Front 13

Myofibrils composed of..

Back 13

Microfilaments

Front 14

Microfilaments composed of...

Back 14

Actin and myosin

Front 15

Protein component of muscle

Back 15

Actin and myosin

Front 16

Each muscle has how many layers of CT?

Back 16

3

Front 17

Connective Tissue provides?

Back 17

oProtection
o sites for blood vessel and nerve distribution
o means of attaching muscle to skeleton.

Front 18

Layers of Connective Tissue

Back 18

Endomysium
epimysium
Deep fascia
superficial fascia

Front 19

Endomysium

Back 19

innermost layer
-surrounds and insulates each muscle fiber

Front 20

epimysium

Back 20

surrounds entire muscle

Front 21

Deep Fascia

Back 21

surrounds epimysium
 Separates muscles, binds muscle with same action

Front 22

Superficial Fascia

Back 22

hypodermis
 Separates muscle from skin.

Front 23

CT merges at end of muscle to form...

Back 23

Tendon

Front 24

Tendon

Back 24

o attaches muscle to bone
o Usually cord-like in appearance
o sometimes flat sheet called an Aponeurosis

Front 25

Aponeurosis

Back 25

Flat sheet of tendon

Front 26

How a muscle attaches 2 bones..

Back 26

Over a joint

Front 27

Least moveable point of attachment

Back 27

Origin

Front 28

Moveable point of attachment

Back 28

Insertion

Front 29

Components of a muscle cell

Back 29

Sarcolemma
Sarcoplasm
Sarcoplasmic Reticulum (SR)

Front 30

Function of Sarcoplasmic Reticulum (SR)

Back 30

Stores C++

Front 31

Two main structures unique to muscle fiber:

Back 31

Transverse Tubules (t-tubules)
Terminal cisternae

Front 32

Transverse Tubules (t-tubules)

Back 32

deep invaginations of sarcolemma
 extend into sarcoplasm
 Carry impulse deep into fiber

Front 33

Terminal cisternae

Back 33

blind sacs at end of SR
 Interact w/ T-tubules to form a triad - two terminal cisternae + one t-tubule

Front 34

triad

Back 34

two terminal cisternae + one t-tubule

Front 35

Myofibrils

Back 35

Sarcoplasm contains 100s-1000s of myofibrils
o extend entire length of cell
o Have ability to shorten.
 results in contraction of muscle

Front 36

Myofilaments

Back 36

 Myofibrils composed of Myofilaments .
o do not run entire length of muscle fiber

Front 37

Myofilaments organized into...

Back 37

sarcomeres

Front 38

2 types of sarcomeres

Back 38

1. Thin filaments – actin and associated proteins
2. Thick filaments -- myosin .

Front 39

Thin filaments

Back 39

actin and associated proteins

Front 40

Thick filaments

Back 40

myosin

Front 41

Thin Filaments
comprised of...

Back 41

two twisted strands
 F-actin or filamentous actin
o Made of G-actin or globular actin
 Two regulatory proteins also part of thin filament:
Tropomyosin
Troponin

Front 42

Troponin

Back 42

binds Ca++

Front 43

Tropomyosin

Back 43

covers binding sites

Front 44

Two regulatory proteins part of thin filament

Back 44

Tropomyosin
Troponin

Front 45

F-actin made of...

Back 45

G-actin
or globular actin

Front 46

Thick filaments
description

Back 46

 2 times as thick as actin
 Composed of bundled molecules of myosin
 Each myosin molecule has a head and elongated tail
 Heads form crossbridges w/actin during contraction

Front 47

Dark bands =

Back 47

A band
contains entire myosin molecule and overlapping portion of actin.

Front 48

Light bands =

Back 48

I Bands
contain thin filaments only
o also contain the protein titin .
 Maintains position of myofilaments

Front 49

Titin

Back 49

Largest protein in the body.

Front 50

Other Components of the A Bands and I Bands

Back 50

1. H zone (H band)
2. M line
3. Z disc (Z band)

Front 51

H zone (H band)

Back 51

– light central region of A
 no filaments

Front 52

M line

Back 52

protein meshwork in H zone
 keeps thick filaments aligned

Front 53

Z disc (Z band)

Back 53

– protein structure in middle of I band
 attachment site for one end of actin

Front 54

Functional unit of contraction

Back 54

Sarcomere

Front 55

Area between 2 adjacent
z discs .

Back 55

Sarcomere

Front 56

True or False:
Myofibrils contain multiple sarcomeres

Back 56

True

Front 57

Each sarcomere shortens as fiber...

Back 57

contracts

Front 58

Mechanism for contraction

Back 58

Sliding Filament Theory

Front 59

Sliding Filament Theory

Back 59

Actin and myosin slide across one another
 Causes shortening of sacromere, NOT filaments .

Front 60

Changes within each sarcomere: 5 steps
(Sliding Filament Theory)

Back 60

o Width of A band remains constant
o H zone disappears
o Z discs move closer together
o Sarcomere narrows in length
o I bands narrow

Front 61

During the Sliding Filament Theory, Length of thick and thin filaments

Back 61

remain the same

Front 62

Impulse in neuron=

Back 62

impulse in muscle fiber

Front 63

impulse in muscle fiber occurs at...

Back 63

Neuromuscular Junctions

Front 64

Components of the Neuromuscular Junction (6)

Back 64

synaptic knob
Synaptic vessels
Motor end plate
Synaptic Cleft
ACH Receptors
Acetylcholinesterate

Front 65

expanded end of the neuron

Back 65

synaptic knob

Front 66

membrane bound sacs filled with acetylcholine(ACh)

Back 66

Synaptic vessels

Front 67

region of sarcolemma across from synaptic knob
 folds and indentations increase surface area .

Back 67

Motor end plate

Front 68

narrow space separating synaptic knob from motor end plate

Back 68

Synaptic Cleft

Front 69

bind to ACh in motor end plate

Back 69

ACH Receptors

Front 70

an enzyme in synaptic cleft that rapidly breaks down ACh

Back 70

Acetylcholinesterate

Front 71

single motor neuron + muscle fibers it controls

Back 71

Motor unit

Front 72

Motor unit
(description)

Back 72

o A motor unit controls only some muscle fibers in an entire muscle
o May be few to hundreds
o Larger muscles  more motor units

Front 73

fiber contracts completely or not at all
o If motor unit is stimulated, all muscle fibers under its control contract

Back 73

All-or-None Principle

Front 74

Strength of contraction regulated by...

Back 74

number/size of motor units stimulated

Front 75

Two types of contraction

Back 75

Isometric
Isotonic

Front 76

muscle length stays same
 Muscle tension does not exceed resistance

Back 76

Isometric

Front 77

muscle fibers shorten
 Muscle tension exceeds resistance
 Results in movement.

Back 77

Isotonic

Front 78

Tense, but no movement

Back 78

Muscle tone
Motor Unit always active

Front 79

–reduction of muscle size, tone and power
o caused by lack of stimulation (exercise)

Back 79

Muscle atrophy

Front 80

increase in muscle fiber size (not #)

Back 80

Muscle hytrophy

Front 81

Muscle hytrophy

Back 81

o results from repetitive stimulation of muscle fibers
o mitochondria increase in number  amount of increases
o Both myofibrils and myofilaments increase in number

Front 82

Three different types of muscle fibers

Back 82

Slow
Intermediate
Fast

Front 83

Ratio of fiber types within a muscle determines:

Back 83

o Speed of muscle’s contraction
o Sustainability of contraction

Front 84

These fibers dominate muscles in back and calf.

Back 84

Slow Fibers
continuaous contraction

Front 85

Do slow fibers exist in muscles that require brief contrations?

Back 85

NO
eg. eye and hand muscles

Front 86

Actions of Skeletal Muscles

Back 86

agonist
antagonist
synergist

Front 87

Prime Mover--produces specific movement
joint

Back 87

agonist
o eg. biceps brachii - agonist that causes flexion of elbow

Front 88

muscle whose action opposes that of an agonist

Back 88

antagonist
eg. Triceps brachii is an antagonist to the biceps brachii

Front 89

Synergist

Back 89

muscle that assists agonist or prime mover.
eg. Brachialis assists biceps brachii

Front 90

Skeletal Muscle Fiber Organization
 four patterns of fascicle arrangements

Back 90

Circular (sphincter)
parallel (very strong)
convergent
pennate

Front 91

Naming of Skeletal Muscles
 Based on specific qualities:

Back 91

o Orientation of fibers
o Shape and size
o Muscle heads/tendons of origin
o Muscle action – generally indicate primary action
o Specific body region
o Muscle attachments

Front 92

Cardiac Muscle
7 Characteristics:

Back 92

1. Striated
2. One or two nucleus .
3. Form Y-shaped branches
4. Join other adjacent cells to form intercalated discs.
 comprised of gap junctions
5. - autorythmic--generate muscle impulse without nervous stimulation
6. Under involuntary control
7. aerobic – many mitochondria for ATP

Front 93

generate muscle impulse without nervous stimulation

Back 93

autorythmic

Front 94

Smooth Muscle
6 Characteristics

Back 94

1. short fusiform cells (widest in middle and tapered at each end)
2. One centrally located nuclues.
3. No striations .
4. Thin filaments attached to dense bodies
5. Under involuntary control
6. slow, fatigue-resistant contractio

Front 95

Smooth muscle found in...

Back 95

walls of viscera and blood vessels

Front 96

Muscles under involutary control..

Back 96

Cardiac
Smooth Muscle