Chapter 10: Muscle Tissue

Smooth muscle is found in which of the following locations?

- In wall of the uterus - Around blood vessels - In the wall of the small intestine

Which can cause muscle fatigue?

-Build up of intracellular P1 - Insufficient Ca2+ - Na+ or K+ imbalances

Place the events that occur at a neuromuscular junction in order.

1st - nerve signal arrives at synaptic knob 2nd - calcium enters and binds synaptic vesicle 3rd - ACh is released via exocytosis into the synaptic cleft 4th - ACh binds receptors on the motor end plate

Area B of the sarcomere represents the _ band.

A

Identify the components of a sarcomere in the picture provided.

A - I band B - A band C - M line D - Z disc

Using the image of a muscle, match the structure with its label in the diagram.

A - blood vessel B - epimysium C - perimysium D - endomysium

Using the picture of the sarcomere, match the indicated structures in the diagram with their name.

A - connectin B - thin filament C - M line D - thick filament

Identify each structure in the diagram of a muscle fiber.

A - mitochondrion B - nucleus C - sarcoplasmic reticulum D - T-tubule

In a muscle there are concentric layers of connective tissues. From deep to superficial these connective tissue layers are the _ , the _ , and the _.

Endomysium, perimysium, epimysium

The three connective tissue layers surrounding the individual components of a muscle are the: _ _ , _ , and _ .

Epimysium, perimysium, endomysium

Muscle cells are said to have what characteristic because they can respond to stimulation from the nervous system?

Excitability

In a transverse section of a muscle, you can see that each skeletal muscle is actually composed of many _ , which are bundles of muscle fibers.

Fascicles

A piano player uses her hands for brief quick movements. Which muscle fiber type would you therefore predict to be predominant in these muscles?

Fast glycolytic

A skeletal muscle cell is also called a muscle _ .

Fiber

In a relaxed muscle fiber there are no thin filaments overlapping the thick filaments in the _ zone.

H

In a sarcomere, the _ zone (or band) is the light, central region of the A band.

H

Match the structure of a sarcomere with its description.

H zone - lighter region in the middle of an A band M line - appears as a dark protein disc in center of H zone Z disc - made of dark proteins that create a zig-zag line I band - light band containing thin filaments only

Each myosin strand has a free _ and an attached tail.

Head

What part of a myosin molecule does ATP bind to?

Head

You make a New Year's resolution to work out more and by March notice your muscles are getting bigger. This is a result of muscle _.

Hypertrophy

When viewed under a light microscope, the light bands, called _ bands, contain only _ filaments.

I; thin

If you strain to push on a wall that does not move, your muscles are in a type of _ contraction.

Isometric

In order to predict how much tension a muscle can produce when contracting, it is important to consider the _ relationship of thick and thin filaments.

Length-tension

The _ filament theory explains how muscle fibers shorten during contraction.

Sliding

Which of the following proteins are found in a thin filament?

Actin

Match the thin filament protein and thin filament associated protein names with its function.

Actin - two intertwined strands; each bead has a myosin-binding site Tropomyosin - two intertwined strands; cover myosin-binding sites Troponin - bound to tropomyosin; can bind calcium ions

Slow and intermediate fibers require oxygen to produce ATP, so the metabolic reactions within these fibers are termed _.

Aerobic

In a muscle cell, the short-term energy is supplied by _ respiration, whereas long-term energy is supplied by _.

Anaerobic; aerobic

Smooth muscle is found where in the respiratory system?

Around the bronchioles

The connective tissue layers in muscle provide protection, distribution sites for blood vessels and nerves, and a means of _ to the skeleton.

Attachment

Match each function of skeletal muscle with its description.

Body movement - Muscles contract and pull on the tendons that attach the muscles to the bones Posture - Contraction of specific skeletal muscles stabilizes joints Temperature regulation - Heat is produced as a waste product of energy usage Storage and movement of materials - Voluntary sphincter muscles of the gastrointestinal and urinary tracts can be kept closed or opened

The act of shivering is an example of skeletal muscle performing what function?

Heat production

If a muscle cell is stimulated to contract, allowed to partially relax, then stimulated again, its force of contraction the second time will be _.

Higher

The diameter of a muscle fiber will predict _.

How much power it will produce

An increase in the number of mitochondria can be observed in _.

Hypertrophy

Multiunit smooth muscle cells are stimulated _.

Individually

Cardiac muscle cells form Y-shaped branches and join to adjacent muscle cells at junctions called _ discs.

Intercalated

When a nerve impulse reaches the end of an axon of a neuromuscular junction, calcium flows _ the synaptic knob.

Into

Smooth muscle contraction is under _ control of the nervous system.

Involuntary

Smooth muscle contraction is under _ control.

Involuntary

Match each stage of a muscle twitch with the amount of tension generated.

Latent period - there is no tension Contraction period - tension increases Relaxation period - tension decreases

The _ line is a thin, transverse, protein meshwork structure in the center of the H zone of a sarcomere.

M

Because muscle cells require a huge amount of ATP in order to contract, they have a large number of which organelle?

Mitochondria

Slow fibers have a relatively large number of _. This permits slow muscle fibers to produce a greater amount of _ than fast muscle fibers while contractions are underway.

Mitochondria; ATP

Athletes have more defined muscles than non-athletes even while at rest because they have _ motor units contracting all the time.

More

Neurons that stimulate muscle contraction are called _ neurons.

Motor

Skeletal muscle contraction is controlled by _ neurons.

Motor

A motor unit is composed of a single _ and all of the muscle fibers it controls.

Motor neuron

A single motor neuron and the skeletal muscle fibers it controls is called a _.

Motor unit

Match the name of the muscle cell component with its function.

Muscle fiber - metabolic activities; contraction Sarcolemma - regulates entry and exit of materials Sarcoplasm - site of metabolic processes for normal muscle fiber activities Sarcoplasmic reticulum - stores calcium ions needed for muscle contraction T-tubule - transports the action potential from the sarcolemma throughout the entire muscle fiber

What is the force generated when a skeletal muscle is stimulated to contract called?

Muscle tension

After the age of 30, the number of _ in existing muscle fibers decreases.

Myofibrils

The sarcoplasm of a skeletal muscle fiber contains hundreds to thousands of long, cylindrical structures called _ that extend the length of the cell.

Myofibrils

The cytoplasm of a skeletal muscle cell has a specific name and is known as _ .

Sarcoplasm

At the end of muscle contraction, calcium ions are moved back into the _ reticulum by ATP-driven ion pumps.

Sarcoplasmic

During the development of skeletal muscle cells, some myoblasts do not fuse and instead become _ cells.

Satellite

If a skeletal muscle is injured, surrounding _ cells may be stimulated to differentiate and assist in its repair and regeneration.

Satellite

Cardiac muscle cells are _ and thicker than skeletal muscle cells, and they have only _ nuclei.

Shorter; 1-2

Attached to the skeleton and surrounding the openings of the urinary and gastrointestinal traces are locations of _ muscle.

Skeletal

Smooth muscle contraction is _ , resistant to _ , and usually sustained for an extended period of time.

Slow, fatigue

A "step-wise" increase in the force of contraction of a single muscle fiber or single motor unit due to repeated stimulation is called _.

Summation

The force generated when a skeletal muscle is stimulated to contract is muscle _.

Tension

As a result of ACh stimulation, calcium ions are released from the _ of the sarcoplasmic reticulum.

Terminal cisternae

The epimysium of a muscle surrounds _.

The entire skeletal muscle

When calcium ions bind to troponin, which of the following then occurs?

The myosin-binding sites on actin are exposed.

Slow-twitch and fast-twitch muscle fibers differ primarily in _.

Their ATPase which splits ATP

The H band (or H zone) is more lightly shaded because only _ filaments are present.

Thick

in a sarcomere, the M line serves as an attachment site for the _ filaments and keeps them aligned during contraction and relaxation.

Thick

Single unit muscle cells contract _.

Together

As you sit there reading this your muscles, even your relaxed ones are not completely relaxed and soft. This is because they have some background tension called resting muscle _.

Tone

The deep invaginations of the sarcolemma that extend into the sarcoplasm of skeletal muscle fibers as a network of narrow membranous tubules are called _.

Transverse tubules

As the troponin changes shape (due to binding calcium), it moves the _ molecule to which it is attached, thus exposing the active sites on the G-actin molecules.

Tropomyosin

Calcium ions bind to what protein in a thin myofilament?

Troponin

Upon release from the terminal cisternae, some calcium ions bind to _ causing it to change shape.

Troponin

Smooth muscle cells retains their mitotic ability.

True

True or false: A single myofibril runs the length of the muscle fiber.

True

True or false: In the absence of calcium, troponin attaches to tropomyosin to hold it in place on the surface of the F actin strand.

True

True or false: Most muscles contain a combination of all three muscle types, slow oxidative, fast oxidative, and fast glycolytic.

True

True or false: Skeletal muscle is usually attached to the skeleton, but it is also found at the openings between the digestive tract and the external environment and the urinary tract and the opening to the external environment.

True

True or false: Smooth muscle cells lack transverse tubules.

True

A single contraction and relaxation of a muscle fiber is referred to as a muscle _.

Twitch

Each myosin protein molecule in a thick filament consists of _ strands.

Two

Thick filaments are about _ the diameter of thin filaments.

Two times

Using the image of a muscle fiber, match each structure in the diagram with its name.

A - sarcolemma B - myofibril C - sarcomere D - myofilaments

When a muscle fiber contracts, which parts of the sarcomere maintain a constant length throughout contraction?

A band

Glycolysis and aerobic respiration are used to generate _ in muscle fibers.

ATP

Functionally, troponin provides a binding site for _ ions.

Calcium

The sarcolemma of smooth muscle cells has small invaginations called _.

Caveolae

A muscle fiber is what level of organization in the body?

Cellular

When smooth muscle is stretched, it responds by _.

Contracting then relaxing

The amount of additional oxygen that must be inhaled in order to restore pre-exercise levels is called oxygen _.

Debt

The epimysium of a muscle is composed of _ connective tissue.

Dense irregular

In an isometric contraction, the muscle ______ body movement.

Does not produce

Muscle tissue demonstrates the property of _ when it is done contracting and returns to its resting length.

Elasticity

True or false: A muscle fiber that is partially shortened can produce a contraction stronger than the contraction it can produce when at its resting length.

False

In a normally functioning muscle, the inability to contract and produce tension is called muscle _.

Fatigue

Overall, as aging progresses, muscle strength and endurance are impaired, and the individual has a tendency to _ quickly.

Fatigue

Smooth muscle is composed of short cells that have a _ shape.

Fusiform

At maximal contraction of a muscle fiber, the thin filaments are pulled into the ______ zone which disappears.

H

Match the muscle fiber component with its function.

Myofibrils - contain myofilaments that are responsible for muscle contraction Thick filament - bind to thin filaments and cause contraction Thin filament - bind to thick filaments and cause contraction Actin - binding site for myosin to shorten a sarcomere Tropomyosin - covers the active sites on actin when muscle cell is at rest

Match the component of a muscle cell with its description.

Myofibrils - cylindrical organelles specialized for contraction Thick filament - composed of myosin Thin filament - composed of actin, troponin, and tropomyosin Actin - double-stranded contractile protein Tropomyosin - double-stranded regulatory protein

Muscle fibers contain cylindrical structures called myofibrils, which are composed of _.

Myofilaments

Myofibrils are made of _.

Myofilaments

Myofibrils consist of bundles of short _.

Myofilaments

Termination of the nerve impulse at an NMJ results in the passive sliding of _ back to their original state.

Myofilaments

Muscle cells store oxygen bound to a _ molecule.

Myoglobin

Thick filaments are assembled from bundles of the protein called _.

Myosin

Thick myofilaments are composed of bundles of _ protein molecules.

Myosin

While observing skeletal muscle tissue under the microscope you note that it appears striated. You tell your lab partner this is because _.

Of the arrangement of myofilaments in each sarcomere

After you stop running, you notice that you keep breathing heavily for some time. This is because your body is in _.

Oxygen debt

As you hold a barbell and begin to flex your arm in a curl, your biceps brachii slowly lifts the weight by using more and more motor units. This phenomenon, which increases the strength of the contraction, is referred to as _.

Recruitment

As you struggle to twist open a jar, more motor units are called into action until you finally generate enough force to open it. This is an example of _.

Recruitment

An internal membrane complex in skeletal muscle cells that is similar to the smooth endoplasmic reticulum of other cells is called the sarcoplasmic _ .

Reticulum

After stimulation of ACh receptors, a muscle impulse spreads quickly along the _ and into the muscle fiber along T-tubules.

Sarcolemma

The plasma membrane of a skeletal muscle fiber is called the _.

Sarcolemma

Match the name of the muscle cell component with its function.

Sarcolemma - plasma membrane of a muscle fiber Muscle fiber - a muscle cell Sarcoplasm - cytoplasm of a muscle fiber Sarcoplasmic reticulum - smooth endoplasmic reticulum in a muscle fiber T-tubule - narrow, tubular extensions of the sarcolemma into the sarcoplasm

Within a myofibril, each _ shortens as the muscle fiber contracts.

Sarcomere

Match the structure of a myofibril with its description.

Sarcomere - functional contractile unit of skeletal muscle A band - dark band containing both actin and myosin H zone - contains thick filaments only I band - light band containing thin filaments only

A contracting skeletal muscle fiber typically shortens as all of its _ shorten in length.

Sarcomeres

Within a myofibril, Z discs separate the functional contractile units known as _.

Sarcomeres