Chapter 10 Muscle Tissue

Front 1

3 types of muscle tissue

Back 1

1. Skeletal muscle tissue
2. Cardiac muscle tissue
3. Smooth muscle tissue

Front 2

Skeletal muscles are:

Back 2

1. attached to the skeletal system

2. allow us to move

Front 3

The muscular system includes

Back 3

only skeletal muscles

Front 4

Six functions of skeletal muscle tissue are:

Back 4

1. Produce skeletal movement

2. Maintain posture and body position

3. Support soft tissues

4. Guard entrances and exits

5. Maintain body temperature

6. Store nutrient reserves

Front 5

Skeletal muscle have:

Back 5

1. Muscle tissue (muscle cells or fibers)

2. Connective tissues

3. Nerves

4. Blood vessels

Front 6

muscles have three layers of connective tissues, these are:

Back 6

1. Epimysium

2. Perimysium

3. Endomysium

Front 7

Epimysium

Back 7

1. exterior collagen layer (dense layer)

2. connected to deep fascia

3. separates muscle from surrounding tissues

Front 8

Perimysium

Back 8

1. surrounds muscle fiber bundles (fascicles)

2. contains blood vessel and nerve supply to fascisles

Front 9

Endomysium

Back 9

1. surrounds individual muscle cells (muscle fibers) and (loosely interconnects adjacent muscle fibers)

*this flexible, elastic connective tissue layer contains:

1. contains capillaries and nerve fibers contacting muscle cells

2. contains myosatellite cells (stem cells) that repair damaged muscle tissue

3. nerve fibers that control the muscle

Front 10

Endomysium, Perimysium, and Epimysium come together:

Back 10

1. at ends of muscles, to form connective tissue attachment to bone matrix

i.e. tendon (bundle) or aponeurosis (sheet)

Front 11

Tendon and Aponeuroses usually attach

Back 11

skeletal muscles to bone (where they contact the bone, the collagen fibers extend into the bone matrix, providing a firm attachment)

Front 12

Muscle have extensive vascular system that:

Back 12

1. supply large amounts of oxygen

2. supply nutrients

3. carry away wastes

Front 13

skeletal muscles are ------------and it is controlled by ---------------of the central nervous system (brain and spinal cord)

Back 13

Voluntary, Nerves

Front 14

Within the endomysium, arterioles(small arteries) supply blood to a

Back 14

Capillary network that services the individual muscle fiber

Front 15

Skeletal muscle cells are:

Back 15

1. Very long

2. Develop through fusion of mesodermal cells (myoblasts)-(groups of embryonic cells)

3. Become very large

4. Contain hundred of nuclei (multinucleate)

Front 16

Skeletal muscle involved with breathing such as:

Back 16

Diaphragm (usually work outside our conscious awareness)

Front 17

Striations are due to the precise arrangements of:

Back 17

thin (actin) and thick (myosin) filaments

Front 18

The Sarcolemma are:

Back 18

1. The cell membrane of a muscle fiber (cell)

2. Surrounds the sarcoplasm (cytoplasm of muscle fiber)

3. A change in transmembrane potential(due to more negative charges on its cytoplasmic side and more positive charges on its extracellular side) begins contractions

Front 19

In a skeletal muscle fiber, a sudden change in the membrane potential is the:

Back 19

first step that leads to a contraction

Front 20

Transverse tubules ( T tubules) are:

Back 20

1. Transmit action potential through cell

2. Allow entire muscle fiber to contract simultaneously

3. Have same properties as sarcolemma

Front 21

T tubules are filled with:

Back 21

extracellular fluid and form passageways through the muscle fiber, like a network of tunnels through a mountain

Front 22

Types of Myofilaments are :

Back 22

1. Thin filaments (made of protein actin)

2. Thick filaments (made of protein myosin)

Front 23

The Sarcoplasmic Reticulum (SR) are:

Back 23

1. A membranous structure surrounding each myofibril

2. Help transmit action potential to myofibril

3. Similar in structure to smooth endoplasmic reticulum

4. Forms chambers (Terminal Cisternae) attached to T tubules

Front 24

Myofibril are:

Back 24

muscle fiber that contains hundreds to thousands of cylindrical structure and it also consist of bundles of protein filaments called myofilaments.

it is in the inner surface of the sarcolemma at the end of a muscle fiber, the outer surface of the sarcolemma is attached to collagen fibers of the tendon or aponeurosis of the skeletal muscle.

Front 25

Mitochondria activity and glucose breakdown by glycolysis provide energy in the form of:

Back 25

ATP for short-duration, maximum-intensity muscular contractions

Front 26

Triad

Back 26

is formed by one T tubule and two terminal cisternae

Front 27

Cisternae

Back 27

1. Concentrate ca2+ (via ion pumps)

2. Release ca2+ into sarcomeres to begin muscle contraction

Front 28

Sarcomeres (the section where contraction takes place from Z line to Z line)

Back 28

1. The contractile units of muscle

2. Structural units of myofibrils

3. Form visible patterns within myofibrils

4. A striped or striated pattern within myofibrils

5. Alternating dark, thick filaments ( A band) and light, thin filaments ( I band)

Front 29

The A band consists of:

Back 29

1. M line

2. H band

3. Zone of overlap

it contains thick (myosin) and thin (actin) filaments

Front 30

M line

Back 30

1. The center of the A band

2. At midline of the sarcomeres (middle)

Front 31

The H band

Back 31

1. The area around the M line

2. Has thick filaments but no thin filaments

Front 32

Zone of overlap

Back 32

1. The densest, darkest area on a light micrograph

2. where thick and thin filament overlap

Here three thick filaments surround each thin filament, and six thin filaments surround each thick filament

Front 33

The A band and the I band are derived from:

Back 33

anisotropic and isotropic

Front 34

Two T tubules encircle each ------------and the triad containing them are located in the --------------at the edges of the A band

Back 34

Sarcomere, Zone of overlap

Front 35

Calcium ions released by the --------------enter the regions where thick and thin filaments can interact

Back 35

Sarcoplasmic reticulum (SR)

Front 36

The I band consists of :

Back 36

1. Z lines

2. Titin

it contains thin filaments but no thick filaments (Actin)

Front 37

Z lines

Back 37

1. The centers of the I bands

2. At the ends of sarcomere

Front 38

Titin

Back 38

1. Are strands of protein

2. Reach from tips of the thick filaments to the Z line

3. Stabilize the filaments

Front 39

The neuromuscular junction (NMJ)

(the control of skeletal muscle activity)

Back 39

1. Special intercellular connection between the nervous system and skeletal muscle fiber

2. Control calcium ion release into the sarcoplasm

Front 40

The contraction cycle are:

Back 40

1. Contraction cycle begins

2. Active-site exposure

3. cross bridge formation

Front 41

A single thin filament contains four proteins:

Back 41

1. F-actin

2. Nebulin

3. Tropomyosin

4. Troponin

Front 42

Filamentous actin or F-actin

Back 42

is a twisted strand composed of two rows of 300-400 individual globular molecules of G-actin

Front 43

Nebulin

Back 43

a long strand extends along the F-actin strand in the cleft between the rows of G-actin molecules. it also holds the F-actin strand together

Front 44

Each G-actin molecules contains an:

Back 44

Active site (where myosin in the thick filaments can bind)

Front 45

Under the resting conditions, the troponin-tropomyosin complex prevents

Back 45

Myosin binding

Front 46

Tropomyosin

Back 46

1. cover the active sites on G-actin and prevent actin-myosin interaction.

2. A tropomyosin molecule is a double-stranded protein that cover seven active sites

3. it is bond to one molecule of troponin midway along it length

Front 47

Troponin

Back 47

1. consists of three globular subunits

2. one subunit binds to tropomyosin, locking them together as a troponin-tropomyosin complex, and a second subunit binds to one G-actin, holding the troponin-tropomyosin complex in position.

3. the third subunit has a receptor that binds two calcium ions

Front 48

In a resting muscle, intracellular Ca2+ concentrations are -----------------and that binding site is -------------

Back 48

very low, empty

Front 49

A contraction can occur only when the troponin-tropomyosin complex ----------------exposing the active sits on actin

Back 49

changes position

Front 50

the necessary change in position takes place when -----------------bind to receptors on the troponin molecules

Back 50

calcium ions

Front 51

The smallest functional units of the muscle fiber is:

Back 51

Sarcomeres

Front 52

Cross-bridges

Back 52

when the myosin (thick) heads interact with thin filaments during a contraction

Front 53

Sliding filament theory

Back 53

when the thin filaments are sliding toward the center of each sarcomere, alongside the thick filaments.

Front 54

Tension

Back 54

applied to an object tends to pull the object toward the source of the tension (active force). energy must be expended to produce it.

Front 55

Compression

Back 55

applied to an object tend to force the object away from the source of the compression (no movement can occur until the applied compression exceeds the load of the object)

Front 56

The cytoplasm of the axon terminal contains vesicles filled with molecules of:

Back 56

Acetylcholine (or ACH)

Front 57

Acetylcholine is a:

Back 57

Neurotransmitter ( a chemical released by a neuron to change the permeability or other properties of another cell's plasma membrane)

Front 58

Synaptic cleft

Back 58

is a narrow space that separates the axon terminal of the neuron from the opposing motor end plate

Front 59

Acetylcholinesterase (ACHE)

Back 59

breaks down acetylcholine (ACH)

Front 60

Exocytosis occurs as vesicles fuse with the:

Back 60

Neuron's plasma membrane

Front 61

ACH molecules diffuse across the synaptic cleft and bind to:

Back 61

ACH receptors on the surface of the motor end plate

Front 62

ACH binding alters the membrane's permeability to:

Back 62

Sodium ions

Front 63

Because the extracellular fliud contains a high concentration of ions, and sodium ion concentration inside the cell is very low, sodium ion rush into the:

Back 63

cytosol

Front 64

the sudden inrush of sodium ions results in the:

Back 64

generation of an action potential in the sarcolemma

Front 65

ACH is removed from the synaptic cleft in two ways:

Back 65

1. ACH either diffuses away from the synapse

2. Or it is broken down by ACHE into acetic acid and choline

Front 66

This removal inactivates the:

Back 66

ACH receptor sites

Front 67

In unstimulated (resting) neurons and skeletal muscle fibers, typically resting membrane potentials are:

Back 67

-70mv and -85mv

Front 68

An influx of sodium ions leads to------------------as the membrane potential becomes less negative

Back 68

Depolarization

Front 69

The movement of the potassium ions out of the cell leads to----------------------as the membrane potential becomes more negative

Back 69

Hyperpolarization

Front 70

A return to the resting potential is called

Back 70

Repolarization

Front 71

Graded potential

Back 71

in most cells, the depolarization or hyperpolarization of a plasma membrane is a localized change limited by the presence or absence of stimulation. it does not continue to spread over the plasma membrane

Front 72

Excitable membranes

Back 72

permit rapid communication between different parts of a cell

Front 73

Voltage-gated channels (found in excitable membrane)

Back 73

are activated and inactivated by changes in the membrane potential

Front 74

These electrical channels become activated when the membranes of neurons and skeletal muscle fibers first depolarize from the resting potential to a threshold potential:

Back 74

from -70 to -60mv for neuron and from -85 to -55mv for skeletal muscle fibers

Front 75

Excitation-contraction coupling

Back 75

the link between the generation of an action potential in the sarcolemma and the start of a muscle contraction. this coupling is occurs at the triad.

Front 76

Neural control

Back 76

a skeletal muscle fiber contracts when stimulated by a motor neuron at a neuromuscular junction. the stimulus arrives in the form of an action potential at the axon terminal

Front 77

Excitation

Back 77

the action potential causes the release of ACH in the synaptic cleft, which leads to excitation-the production of an action potential in the sarcolemma

Front 78

Release of calcium ions

Back 78

this action potential travels along the sarcolemma and down T tubules to the triads. this triggers the release of calcium ions (ca2+) from the terminal cisternae of the sarcoplasmic reticulum

Front 79

Contraction cycle begins

Back 79

the contraction cycle begins when the calcium ions (ca2+) bind to troponin, resulting in the exposure of the active sites on the thin filament. this allows cross-bridge formation and will continue as long as ATP is available. it also begins with the arrival of calcium ions (ca2+) within the zone of overlap in sarcomere

Front 80

Active-site exposure

Back 80

calcium ions bind to troponin, weakening the bond between actin and the troponin-tropomyosin complex. the troponin molecule then changes position, rolling the tropomyosin molecule away from the active sites on actin and allowing interaction with the energized myosin head

Front 81

Cross-bridge formation

Back 81

once the active sites are exposed, the energized myosin head bind to them, forming cross-bridge

and without cross-bridge formation contraction ends