NAME _______________________________ COURSE __________________

BIO 210: Anatomy and PhysiologyText: Fundamentals of Anatomy and Physiology 9ed.Chapter 10—MUSCLE TISSUEMUSCLE TYPES

Skeletal Muscle—

Cardiac Muscle—

Smooth Muscle—

SKELETAL MUSCLE FUNCTIONS

Movement—

Posture—

Supports Soft Tissues—

Stabilizing Joints—

Guards Openings—

Generate Heat—

Stores Nutrients—

MUSCLE STRUCTURE (Figure 10-1)

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Muscle fibers—muscle _______________, thousands of these make up a muscle

Epimysium—dense layer of ______________________ that surrounds the entire muscle; connects to ________________________________

Perimysium—divides muscle into compartments; within each compartment is a bundle of muscle fibers called a _____________________

Endomysium—surrounds individual _________________________________; flexible, _______________________________________ contains capillaries, nerve fibers, and _______________________________________

These three layers fuse at the end of a muscle to create a tendon or aponeurosis (sheet of connective tissue) that attaches to a bone

Tendons—fibrous connective tissue (collagen, very tough) that merges with the periosteum of bones. Connects muscles to bones or other muscles

Origin—

Insertion—

MUSCLE CELL FEATURES

Extremely _________________ cells

_____________________________ (hundreds of nuclei per cell)

Myoblasts are ________________________ muscle cells that _________________ during development contributing to the two features above

_____________________________ cells are myoblasts that have not ___________________ and are found in adult muscle tissue (Figure 10-2); they are _________________________ that aid in muscle repair

The ______________________ is the muscle cell membrane and the _____________________ is the cytoplasm of a muscle cell

_______________________ or transvers tubules (Figure 10-3) are extensions of the ___________________________ and run deep into the muscle cell so that an

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_____________ ________________________ can effectively ______________________ a muscle cell quickly and completely

________________________ are cylindrical structures within a muscle fiber and contain the ____________________ responsible for _______________________; hundreds to thousands in each cell and they run the entire ___________________________ of the cell and attach at the ends to a ________________________

________________________________ are the bundles of _________________ filaments within myofibrils; they contain _____________, ________________, and ______________

Actin is a __________________ protein filament

Myosin is a _________________ protein filament

High amounts of ____________________ and ____________________________ are found scattered among the myofibrils for high __________________ production

A ______________________________ is a modified form of the ____________________________ and is found in muscle cells

When the SR fuse and form expanded chambers, this is called _______________________

A ___________________ is combination of a pair of terminal cisternae and a T-Tubule

The SR is a reservoir for ______________________ that can be released into the ________________________ to stimulate __________________

SARCOMERES (Figure 10-4, 10-7)— THIS IS THE FUNCTIONAL UNIT OF THE MUSCLE, a chain of smaller contractile units within the myofibril

Thin and thick filaments of the sarcomere give it a banded appearance

_______ bands are the dark bands found at the _______________ of each sarcomere

o M Line—found in the _________________ of the ______ band; connect neighboring thick filaments

o H Band—a lighter region on either side of the M Line; contains ____________ filaments but no ____________ filaments

o Zone of Overlap— (Figure 10-5) dark region where thin filaments and thick filaments ____________________; ______ thick filaments surround each thin filament and ______ thin filaments surround each thick filament

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_______ bands are the light bands containing thin filaments only and extend from the A band of one sarcomere to the A band of the next sarcomere

o Z line—protein discs that are the end lines of a sarcomere and interconnect _____________________________ of adjacent sarcomeres; actin (thin filaments) attach to the Z line on each end of the sarcomere; Z lines give ________________ _________________ its striped appearance

o Titin—_______________ protein strands that anchor ___________________ to the _____________________; inhibits muscles from stretching too far

ACTIN AND MYOSIN (Figure 10-7)

ACTIN—contains _______________________________________ to aid in contraction; also contains ____________________ and _____________________ which are inhibitory proteins that prevent actin from sliding with _________________

MYOSIN—contains a ________________________ that interacts with the thin filament (actin), forming a __________________________________________

NEUROMUSCULAR JUNCTION—where the motor neuron terminates on the muscle fiber; each muscle fiber has its own neuromuscular junction that controls it

Axon terminal—enlarge tip of the motor neuron containing sacs of the neurotransmitter, acetylcholine.

Sarcolemma—muscle fiber cell membrane. Contains receptor sites for acetylcholine (neurotransmitter) and acetylcholinesterase (inactivator)

T tubules—inward folds of the sarcolemma which carry the action potential to the interior of the muscle cell

Synapse—the small space between the axon terminal and the sarcolemma

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EXCITATION-CONTRACTION COUPLING—the link between the action potential in the sarcolemma and the start of a muscle contraction

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To contract a muscle is to ________________________ a muscle

During contraction: 1. all the sarcomeres shorten, 2. the muscle fibers contract. 3. H bands and I bands get smaller, 4. zones of overlap get bigger, 5. Z lines move closer together, and 6. A bands remain the same

ARRIVAL OF THE ACTION POTENTIAL

1. A nerve impulse arrives at the _____________________________, ________________________ is released into the synapse

2. The sarcolemma receives the acetylcholine into its ___________________________ and which causes _____________________ to rush in the cell

3. The sarcolemma is now ____________________________, the ________________________ bring the action potential to the interior of the muscle cell

4. _______________________________________ inactivates acetylcholine immediately

5. In response to depolarization, _________________ are released from the cisternae of the sarcoplasmic reticulum into the sarcoplasm; the Ca+ binds to the __________________________________ complex to free up the myosin receptor sites on the actin filament

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6. Myosin splits ATP to release energy, myosin ___________________________ attach to actin’s _______________________________ and pulls actin filaments towards the ____________________ of the sarcomere

7. All the sarcomeres ______________________, the entire muscle fiber ____________________

THE CONTRACTION CYCLE OF THE SLIDING FILAMENT THEORY—

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Resting Sarcomere—myosin heads are charged, pointing away from the M Line

Contracted Sarcomere—ATP splits and continues to ‘re-cock’ the myosin heads as long as there is sufficient calcium available

How Long Does a Contraction Last—depends on 3 things:

1. period of ______________________ at the neuromuscular junction2. presence of ___________________ in the sarcoplasm3. amount of ___________ available

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MUSCLE TONE—muscles are always in a state of slight contraction except in certain stages of sleep

Alternate muscle fibers contract so the muscle does not ______________________

A muscle with little muscle tone appears _____________________________________

Muscle tone maintains ______________________

Helps prevent sudden uncontrolled changes in ______________________________________

Allows for ________________________________ when bumped

Strong muscle tone makes muscles appear _____________ and ______________________, even at rest

Good muscle tone improves ______________________________. When muscles are slightly contracted, they can ________________ more quickly and with greater _________________________

Good muscle tone increases a _________________________________ which can aid in exercise and _____________________________

EXERCISE—improves muscle tone

Isotonic contraction—tension rises and a muscle’s length changes bringing about ______________________________

o Concentric contraction—

o Eccentric contraction—

Isometric contraction—the muscle as a whole does not change ___________________ because the tension produced never exceeds the load; contraction without _______________________________

RETURNING A MUSCLE TO RESTING LENGTH—muscles can actively shorten, but they cannot actively lengthen

Elastic Forces—recoil or rebound to the original length

Opposing Muscle Contractions—the contraction of opposing muscles can return a muscle to its resting length

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Gravity—muscles relax and gravity pulls a limb down and stretches the muscle to the resting length

ENERGY SOURCES FOR MUSCLE CONTRACTION

ATP—there is not enough stored in muscles and it is depleted quickly so it has to be generated quickly

Creatine phosphate—ATP that is not being used by a resting muscle is transferred to creatine to be stored for later

In a reverse reaction, creatine phosphate can return the phosphate to ADP and “recharge” the ADP

The enzyme _______________________________ facilitates this reaction; when high amounts are found in the blood concentration, it indicates ___________________________

Glycogen—most abundant energy source in muscles. Broken down to _______________ then glucose broken down to ____________________ to form ____________ through the _____________________________; glycogen is important for _____________________________

ANAEROBIC METABOLISM—provides a small amount of ATP within a muscle cell

1. glycolysis occurs within the sarcoplasm (glucose is broken down into two pyruvate molecules in the absence of oxygen; this makes glycolysis anaerobic)

glycolysis makes very small amounts of ATP (2 molecules) which can be used by the cell when energy demands are at a maximum and oxygen is limited

AEROBIC METABOLISM—provides 95% of ATP production in a resting cell by the break down of fatty acids; when a cell becomes active, it begins to break down pyruvate instead allowing for extensive energy production

2. mitochondria absorb the pyruvate3. a CO2 molecule is removed from each pyruvate molecule within the mitochondria4. the remainder of the pyruvate enters the citric acid cycle, or Kreb’s cycle which breaks down the

pyruvate into CO2 and H+

5. H+ are transferred to oxygen atoms to form water6. all of these steps ultimately support the conversion of ADP to ATP

Every molecule of pyruvate fed into the citric acid cycle produces 17 ATP molecules

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MUSCLE FATIGUE—

Normal muscle function requires:

1.

2.

3.

4.

Muscle can fatigue due to:

1. depletion of _____________________ reserves2. damage to _________________________ or _____________________________________3. decrease in ________ which affects proper __________________________ binding4. decreased _________________ to continue activity due to ____________ and

______________________________

Lactic Acid Build-up—at peak levels of muscle activity, ________________________ builds up in the cell faster than _____________________________ can utilize it; it converts at this point to ________________________ which releases hydrogen molecules and lowers the ________ of the sarcoplasm

RECOVERY PERIOD—

Lactic Acid Removal and Recycling—muscles can continue to contract in the absence of oxygen due to glycolysis…but at the expense of producing ______________________ and lowering tissue ____________________________

During recovery oxygen levels become _____________________ again

Lactic acid can be converted back to ___________________ in the presence of ____________________

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Pyruvate is then used to boost _______________________ reserves or to generate more _____________________ for normal cell function

Oxygen Debt—the amount of oxygen needed to restore pre-exertion conditions

during exertion, _____________________ has been depleted, in recovery, we ______________________________ some oxygen

during recovery, oxygen demands remain ________________________ above normal

the oxygen needed is for restoring _____________, ____________, and ___________________ reserves to their former concentrations

Recovery oxygen uptake—

TYPES OF SKELETAL MUSCLE FIBERS—fast, slow, and intermediate

Fast Fibers most common large in diameter densely packed myofibrils large glycogen reserves few mitochondria produce powerful contractions because of the high number of myofibrils fatigue rapidly because they use ATP in large amounts and not enough

mitochondria to make more prolonged activity supported by anaerobic metabolism

Slow Fibers half the diameter of fast fibers more resistant to fatigue than fast fibers numerous mitochondria higher oxygen supply due to more capillary networks available

contain myoglobin, a red pigment that carries oxygen within muscle cells; makes the muscles with slow fibers dark red in color

Intermediate Fibers appearance is closer to fast fibers (little myoglobin and appear pale) function is between fast and slow fibers

White Muscles—dominated by ____________________________; pale and used for power

Red Muscles—dominated by ________________________; _______________________ and ___________________________ give it a red color

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MUSCLE HYPERTORPHY AND ATROPHY

Hypertrophy—muscle fibers ___________________________________ due to an increased number of ______________________________; causes by repeated and intense stimulation

Atrophy—reduction in muscle size due to lack of ______________________________; muscle loses _________________ and _________________; reversible at first, but if muscle fibers die, they are not replaced

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