Chapter 10, Biology Chapter 10

The connections between the nervous system and skeletal muscle that allow for voluntary control of movement.

True

The contraction phase of a muscle twitch has a shorter duration than the relaxation phase.

True

The embryonic-like cells that remain in adult skeletal muscle tissue are known as satellite cells.

True

The floor of the pelvic cavity includes skeletal muscles that function to support organs in that cavity.

True

The number of satellite cells in skeletal muscle steadily decreases with age.

True

When a skeletal muscle is at rest, there is more sodium outside the cell as compared to the sarcoplasm.

True

Identify the components of a smooth muscle cell in the picture.

A -> intermediate filaments B -> caveolae C -> varicosity D -> dense plaque

The repolarization of the action potential involves the opening of

Voltage-gated K+ channels

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

To initiate a smooth muscle cell contraction, calcium enters the cell and binds to

Calmodulin, which the binds to and activates myosin light-chain kinase

The type of muscle fibers that are striated, form Y-shaped branches, and are joined by intercalated discs are

Cardiac

One of the most crucial factors in the development of fatigue appears to be a depletion of ATP.

False

Satellite cells are multinucleate.

False

Similar to skeletal muscle cels, all smooth muscle cells are excited by ACh.

False

Smooth muscle cells tend to be shorter but thicker than skeletal muscle cells.

False

The fat and connective tissue that encircle a beef steak from endomysium.

False

The metabolic reactions within fast-twitch fibers derive much of their energy from aerobic respiration.

False

The neuromuscular junction is usually located at one of the 2 ends of the muscle fiber.

False

The return of a contracted muscle fiber to its resting length is an active (energy requiring) process.

False

Each skeletal muscle is composed of _______ fascicles, which are bundles of muscle fibers.

Fascicles

Muscles of the eye and hand have a high percentage of _____ fibers.

Fast-twitch

The most prevalent of skeletal muscle fibers in the body are _____ fibers.

Fast-twitch

"intermediate fiber" is another name for

Fast-twitch, oxidative fiber

A reduced ability to generate tension due to recent exertion of force is known as muscle ______

Fatigue

During aging, muscle is often replaced by dense connective tissue, a process called ______.

Fibrosis

Which letter is associated with the light band and contains thin filaments only?

I

When tension output exceeds resistance and the muscle exerts a constant force as it changes length, the contraction is described as _____.

Isotonic

A graph of a muscle twitch contains 3 periods. The period during which there is no change in external muscle tension (and no change in muscle length) is the _______ period.

Latent

Events of excitation contraction coupling, such as the release of calcium from intracellular stores, occur during the ______ period of muscle twitch.

Latent

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

M

Match each protein with its function.

MLCK -> phosphorylates myosin Calmodulin -> binds calcium MLCP -> dephosphorylates myosin

Possible functions of skeletal muscles

Maintenance of posture, both highly coordinated and localized simple movements, temperature regulation, support of certain body organs, regulation of the movement of material through certain body tracts

The vascular supply to slow-twitch muscle fibers in ________ the network of capillaries around fast-twitch muscle fibers.

More extensive than

The neurons that stimulate muscle contraction are called _______ neurons

Motor

Smooth muscle tissue in which cells are individually sent signals to contract (rather than contracting in unison) is referred to as

Multiunit

The iris of the eye contains

Multiunit smooth muscle

When someone engages in exercise that requires more oxygen than is available, they develop an __________ __________ which results in heavy breathing for several minutes after the exercise is complete.

Oxygen debt

ACh is an acronym for .

acetylcholine

To start a muscle contraction, a nerve impulse causes ______ release at a neuromuscular junction.

acetylcholine

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

actin

For longer contractions, muscle cells obtain ATP by which process?

aerobic respiration

The action potential of a muscle fiber occurs

along the sarcolemma and down the T-tubules

The endomysium is composed of what type of connective tissue?

areolar

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

attachment

Functionally, troponin provides a binding site for ions.

calcium

The sarcoplasmic reticulum stores ions needed to initiate muscle contraction

calcium

What muscle type(s) would you expect to find in thew cardiovascular system?

cardiac and smooth

The invaginations of the sarcolemma on the smooth muscle cell pictured are called .

caveolae

The long tails of the myosin molecules in the thick filaments point toward the of the filament.

center

As a result of muscle fiber contraction, thick filaments in neighboring sarcomeres move .

closer together

A (An) ______ contraction of the arm muscles allowed you to lift a book from the table, while (an) ______ contraction of the arm muscles allows you to lower the book back down to the table.

concentric/eccentric

Which of the following proteins are found within a sarcomere?

connectin and actin

The shortening of muscle cells is called , a property that allows muscle cells to cause body movement.

contraction

Match the structures with their functions

cytoskeleton network -> intermediate filaments anchoring point between intermediate filaments and the sarcoplasm -> dense body anchoring point between intermediate filaments and the sarcolemma -> dense plaque

A sheet of dense irregular connective tissue that is external to the epimysium and separates individual muscles is the .

deep fascia

The expansive sheet of dense irregular connective tissue that separates individual muscles is called the .

deep fascia

Muscular dystrophy results from the lack of or an abnormal structure of which protein?

dystrophin

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

elasticity

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

excitability

In a muscle, the perimysium surrounds muscle cells.

fascicles of

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

The majority of skeletal muscle fibers in the body are fibers.

fast glycolytic

Which of the three skeletal muscle fiber types has the largest diameter and provides both power and speed?

fast glycolytic

If used repeatedly for endurance events, fibers can develop the appearance and functional capabilities of fibers.

fast/intermediate

The smaller the motor unit, the the control.

finer

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

fusiform

The multiple nuclei in skeletal muscle cells are the result of the

fusion of myoblasts

One feature that helps provide fast energy to a muscle cell is the presence of granules containing the complex carbohydrate

glycogen

With endurance training, it is possible for fast fibers to take on characteristics of fast fibers.

glycolytic/oxidative

In a muscle contraction, as increasing numbers of motor units are recruited force is exerted.

greater

Each myosin strand has a free and a attached tail.

head

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

An increase in muscle fiber size is called .

hypertrophy

Match the duration of a single muscle contraction with the source of ATP

immediate - > creatine phosphate short term - > anaerobic respiration long term - > aerobic respiration

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

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

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 c contractions are under way.

mitochondria/ATP

The vascular supply to slow muscle fibers is than the network of capillaries around fast muscle fibers.

more extensive

Although muscle fibers obey the all-or-none principle, the force of muscle contraction can be varied depending on how many ______ units are used.

motor

In a motor unit, a single neuron typically controls numerous muscle fibers in a muscle.

motor

Skeletal muscle contraction is controlled by neurons.

motor

Upon release from the synaptic knob, acetylcholine attaches to receptors on the .

motor end plate

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

Match each muscle unit with the connective tissue layer that surrounds it.

muscle-> epimysium fascicle-> perimysium muscle cell-> endomysium

During development, many groups of fuse to form single skeletal muscle fibers.

myoblasts

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

An extensive network of blood vessels and nerve fibers extends through both the epimysium and the of a muscle.

perimysium

Contraction of specific skeletal muscles stabilizes joints and helps maintain the body's by holding the head and truck erect.

posture

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

The endomysium contains fibers to help bind together neighboring muscle fibers

reticular

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

reticulum

The functional contractile unit of a skeletal muscle fiber is known as a .

sarcomere

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

sarcomere

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

sarcomeres

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

sarcoplasm

At the end of contraction, when the stimulation from the nerve impulse ceases, calcium ions are pumped back into .

sarcoplasmic reticulum

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

satellite

Concentric isotonic contractions actively _________ a muscle.

shorten

In an isotonic contraction, the muscle fibers ________, resulting in movement.

shorten or lengthen

Match the muscle tissue with its conduction speed.

skeletal -> fast cardiac -> moderate smooth -> slow

The filament theory explains how muscle fibers shorten during contraction.

sliding

Over longer distances, runners who have higher proportions of muscle fibers in their leg muscles are able to outperform runners who have a greater number of muscle fibers in their leg muscles.

slow/fast

The type of muscle that forms the majority of the walls of the digestive tract is muscle.

smooth

The muscle that surrounds the opening of your esophagus and opens reflexively to allow you to swallow food is what type of muscle?

sphincter

Cardiac muscle cells are like skeletal muscle fibers.

striated

Although smooth muscle cells have both thick and think filaments, they are not precisely aligned so no visible are present.

striations

The superficial fascia is also known as the .

subcutaneous layer

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

One of the names for the areolar connective tissue and adipose connective tissue that separates muscle from skin is ______________ fascia.

superficial

The narrow space that separates the motor neuron and the skeletal muscle fiber in a neuromuscular junction is called the

synaptic cleft

A cord-like structure that attached a muscle to a bone is a .

tendon

Inside a muscle cell, the sacs of the SR where calcium is stored and released from are the .

terminal cisternae

The epimysium of a muscle surrounds .

the entire skeletal muscle

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

thick

Under the microscope the dark(A) bands observed in skeletal muscle contain filaments.

thick and thin

In a sarcomere, Z discs serve as anchors for .

thin filaments

Acetylcholine is released from a neuron

through exocytosis when a vesicle fuses with the membrane

Single unit muscle cells contract ____.

together

In a muscle cell at rest, the myosin heads of a thick filament point the sarcomere.

towards the ends of

Thin filaments in smooth muscle cells contain which proteins?

tropomyosin actin

Two regulatory proteins associated with thin filaments are:

tropomyosin and troponin

T of F: Most muscles contain a combination of all three muscle types, slow oxidative, fast oxidative and fast glycolytic.

true

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

twitch

Thick filaments are about the diameter of thin filaments

two times

In general, fast-twitch fibers generate less power than slow-twitch fibers.

False

T or F: A single myofibril runs the length of the muscle fiber.

True

T or F: Smooth muscle cells lack transverse tubules.

True

T or F: Smooth muscle cells retains its mitotic ability.

True

The T-tubules and sarcoplasmic reticulum are unique to muscle fibers.

True

Which are characteristics of oxidative fibers? Check all that apply.

-good for endurance -red -use aerobic respiration -high concentration of myoglobin

Which are characteristics of glycolic fibers? Check all that apply.

-low concentration of myoglobin -white

In which activities are muscles in an isometric contraction?

-sitting up very straight -holding a yoga pose -pushing on a locked door

The net energy yield from one glucose molecule through the process of glycolysis is

2 ATP

Each thick filament contains about _______ protein molecules (each molecule has 2 heads and 2 braided tails).

200

A typical skeletal muscle cell contains approximately ______ mitochondria.

300

What is the letter associated with the dark bands in sarcomere?

A

A power stroke involves

A myosin head pulling a thin filament toward the center of the sarcomere

A motor unit consists of

A single motor neuron and the multiple muscle fibers it controls

Identify the components of a sarcomere in the picture.

A- I band B- A band C- H zone D- M line E- Z disc

Identify each type of muscle contraction pictured

A- isometric B- concentric istonic C- eccentric isotonic

Match the structure with the label in the diagram.

A-> ACh B-> ACh receptor C-> calcium D-> sarcoplasmic reticulum

Match the structure with the label in the diagram.

A-> synaptic cleft B-> synaptic vesicle C-> ACh receptor D-> terminal cisternae

Identify each stage of cross bridge cycling in the picture

A. Ca2+ binds troponin; myosin binding sites uncovered B. cross bridge formation C. power stroke D. release of myosin head by ATP E. reset of myosin head

For relaxation to occur

ACh receptors close and Ca++ channels on the sarcoplasmic reticulum close

Skeletal muscle contraction requires large amounts of energy in the form of _______ in order to complete the sequence of cyclic events that lead to sarcomere shortening.

ATP

Which is the neurotransmitter that causes the release of calcium ions from reservoirs within the muscle cell and thereby initiates the steps of contraction?

Acetycholine

The enzyme _________ resides in the synaptic cleft and breaks down molecules of ACh.

Acetylcholinesterase

Which of the following structures has the active sites to which of the heads of the thick filaments will bind?

Actin

Proteins found in thin filaments

Actin, Troponin, Tropomyosin

The presence of mitochondria and myoglobin facilitate _______ respiration in muscle cells.

Aerobic

Lifting weights will cause muscles to enlarge. This is primarily due to

An increase in the size of muscle cells

Glycolysis is an

Anaerobic process that occurs in the cytosol

A flat, thin structure made of dense connective tissue that serves to attach a muscle to a bone (or to another muscle) is an

Aponeurosis

Fibers from one motor unit

Are dispersed throughout most of the muscle

A term that describes the change in muscle following a lack of exercise is

Atrophy

What sequence correctly lists the changes that allow the thick and thin filaments to slide past one another in skeletal muscle contraction?

Attach-pivot-detach-retum

The branch of the nervous system that helps govern smooth muscle contraction is the _______ nervous system.

Autonomic

Acetylcholine exerts its effect by

Binding to receptors at the motor end plate

During muscle contraction, myosin heads attach to actin and thereby form connections called _____.

Crossbridges

When a muscle relaxes

Crossbridges stop forming and muscle elasticity returns the muscle to rest length

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 waster product of energy usage storage and movement of materials-> voluntary sphincter muscles of thew gastrointestinal and urinary tracts can be kept closed or opened

Growth of uterus during pregnancy is accomplished by _____ of its smooth muscle.

Both hypertrophy and hyperplasia

The property of muscle tissue that allows an impulse to travel down the entire length of the cell membrane is

Conductivity

Relaxation is facilitated by the release of passive tension that developed in cablelike ________ proteins that were compressed during contraction.

Connectin

In general, a skeletal muscle is composed of

Connective tissue sheaths, nerves, arteries, veins, and muscle fibers

With increased age, skeletal muscles show

Decrease in number of myofibrils

Rather than tightly coupled synapses between neurons and muscle cells, single-unit smooth muscle contains

Diffuse junctions where neuron varicosities are responsible for neurotransmitter release

When a muscle is isometrically contracted, its length _____ change.

Does not

________ is a protein that anchors myofibrils that are adjacent to the sarcolemma to proteins in the sarcolemma.

Dystrophin

Muscles that are used for precisely controlled movements generally contain large motor units.

False

Myosin kinase catalyzes the transfer of Pi from creatine phosphate to ADP

False

The spring-like property that returns muscle to its original length after a connection ends is

Elasticity

A drug that inhibited acetylcholinesterase would result in

Enhanced stimulation of the muscle due to decreased ACh breakdown

When an impulse arrives at the knob of the motor neuron, calcium

Enters through voltage-gated channels and triggers the release of transmitter

Which is the correct order of the connective tissue layers of a skeletal muscle, beginning with the most superficial?

Epimysium, Perimysium, Endomysium

The _________ is the innermost connective tissue layer that surrounds each muscle fiber.

Eudmysium

The characteristic of muscle that allows it to be passively stretched is

Extensibility

In a thin filament, individual G-actin molecules are strung together to form .

F-actin

A sup-threshold stimulus evokes only a small muscle twitch instead of a full tetanic contraction.

False

Because skeletal muscle cells are so close together, muscle contains very few blood vessels.

False

Energy requirements for smooth muscle contractions are generally higher than those for skeletal muscle contractions.

False

Glycolytic muscle fibers tend to be very rich in myoglobin and mitochondria.

False

If someone is engaged in six minutes of vigorous exercise, nearly all of the ATP used is generated by phosphate transfer.

False

In a graph of wave summation, the tension level returns to baseline between each peak of force.

False

In a lab, wave summation is demonstrated by increasing the ______ of the stimulus.

Frequency

One of the reasons you might struggle to lift a heavy object with your arm fully extended is because

Full extension results in decreased overlap between thick and thin filaments in the muscle

In each helical strand of F-actin, many small, spherical molecules are connected to form a long filament resembling a string of beads. Each spherical molecule is called .

G-actin

A motor unit within the powerful quadriceps muscle would

Generally contain several hundred fibers

One feature that helps provide fast energy to a muscle cell is the presence of granules containing the complex carbohydrate

Glycogen

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

H

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

H

Which letter is associated with a zone (in a relaxed muscle) that is a little more lightly shaded because only thick filaments are present?

H

Match the structure 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

The top long-distance runners probably have ______ proportions of slow muscle fibers in their leg muscles.

Higher

An increase in the size of a muscle fiber is called _____.

Hypertrophy

Phosphate transfer is used for

Immediate ATP needs and is not dependent on oxygen

During which phase of the crossbridge cycle is ATP split into ADP and Pi?

Immediately preceding the resetting of the myosin head

Muscle ton is a result of ______, nervous activity and it acts to joint position.

Involuntary, stabilize

Which contraction occurs when you try (unsuccessfully) to move a wall?

Isometric

A skeletal muscle cell contains hundreds to thousands of ________, which are complex organelles, they are cylindrical in shape-about 2 micrometers in diameter and as long as the cell

Myofibrils

What is the correct listing of the hierarchy of a skeletal muscle's components, beginning with the smallest?

Myofibrils, Muscle fiber, Fascicle, Skeletal muscle

Which protein makes up the thick filaments?

Myosin

The electron transport system refers to the oxidative phosphorylation using the coenzymes FADH2 and

NADH

The junction between an axon and the muscle fiber itself is called a ____ junction.

Neuromuscular

Myoglobin is a molecule within muscle cells that can bind

Oxygen

The type of muscle fibers that have only a single nucleus, both thick and thin filaments, but no Z discs, are

Smooth

The _______ is the connective tissue covering of a fascicle.

Perimysium

Increased phosphate ion concentration is believed to contribute to fatigue by interfering with

Phosphate release by myosin heads during crossbridge cycling

For a sprint lasting 60 seconds, ATP is supplied primarily by

Phosphate transfer and glycolysis

Within smooth muscle cells, intermediate filaments are linked by dense _____ at points where they attach on inner surface of cell membrane.

Plaques

An end plate of potential is an event that involves a gain of

Positive charge along the inside of the cell membrane, as sodium rapidly enters

Consider the difference between lifting a light pad of paper versus a heavy textbook. The primary way the level of force of muscle contraction is controlled by

Recruiting a different number of motor units

The increase in muscle tension that occurs with an increase in the intensity (voltage) of a stimulus is called

Recruitment

Oxidative fibers are

Red and fatigue-resistant

Which may occur as a result of muscle atrophy?

Reduction in muscle size, fibers become weaker, muscle loses ton, fibers waste away and die

Release of crossbridges and a decline in muscle tension characterize the _____ period of a twitch.

Relaxation

When smooth muscle is stretched for a prolonged period of time, it responds by

Relaxing

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

Sarcolemma

Match the name of the component of a muscle fiber with its description

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

The functional contractile units of a skeletal muscle fiber is called a ______.

Sarcomere

For relation to occur

Sarcoplasm calcium levels fall, calcium is removed from troponin, and tropomyosin blocks binding sites on actin

The membranous network that wraps around myofibrils and hold relatively high concentrations of calcium is known as the

Sarcoplasmic reticulum

The most abundant form of smooth muscle is

Single-unit, which is also known as visceral smooth muscle

The type of fibers specialized to continue contracting for extended periods of time, as would be required in running a marathon, for example, are ______ fibers.

Slow-twitch

Which fibers dominate many of the back and calf muscles that contract almost continually to maintain posture?

Slow-twitch

__________ muscle fibers have large myoglobin stores, slow contraction velocity, and the highest resistance to fatigue.

Slow-twitch

The latchbridge mechanism of myosin is a property of ______ muscle.

Smooth

A circular muscle band that contracts at an orifice is also known as

Sphincter

One of the names for the areolar connective tissue and adipose connective tissue that separates muscle from skin is ______ fascia.

Superficial

Which structures are reservoirs that store acetylcholine?

Synaptic Vesicles

The narrow space that separates the motor neuron and the skeletal muscle fiber in a neuromuscular junction is called the

Synaptic cleft

Invaginations of the muscle cell membrane that extend deep into the cell are known as the

T-tubules

The structures responsible for attaching muscles to bone is a

Tendon

Which are the reservoirs that store the calcium required for muscle contraction?

Terminal cisternae

A continuous, smooth contraction of muscle in which twitches are fully fused is referred to as ________

Tetany

What is true of a muscle fiber at rest?

There is a charge difference across the sarcolemma. Sodium-potassium pumps are active.

"Staircase" and "warming-up effect" refer to _________ an increased muscle response to a constant stimuls.

Treppe

On a muscle fiber, the 2 terminal cisternae and the centrally placed T-tubule for a structure called a _____.

Triad

When a muscle fiber is in a relaxed state, the molecules cover the G-actin active sites, preventing interaction between thick filaments and thin filaments

Tropomyosin

The calcium ions involved in skeletal muscle contraction bind to a _______ subunit.

Troponin

Aerobic respiration involves the oxidation of pyruvate.

True

Cardiac muscle cells tend to be thicker and shorter than muscle cells.

True

Compared to slow-twitch fibers, fast twitch fibers respond to a stimulus with less delay and with a shorter contraction duration.

True

Deep fascia is also known as muscular fascia; it is composed of dense irregular connective tissue.

True

During REM sleep, muscle tone decreases significantly.

True

During skeletal muscle contraction, more focus is created when more motor units are activated.

True

During skeletal muscle fiber contraction, the I bands and H zones arrow,

True

Heavy breathing to compensate for an oxygen debt helps the body convert lactate to glucose.

True

In an isotonic contraction, the tension produced exceeds the resistance and muscle fibers will shorten.

True

In general, a muscle's resting length is its optimal length for force generation.

True

In the hierarchy of skeletal muscle fiber components, the myofibril is made up of myofilaments.

True

Myosin light-chain phosphate is an enzyme that dephosphorylates the myosin heads in smooth muscle, which stops ATPase activity and fosters relation of smooth muscle.

True

One's genes have a greater impact than exercise habits in determining the proportion of fast-twitch and slow-twitch fibers throughout the body.

True

Slow-twitch fibers are specialized to continue contracting for extended periods of time without experiencing fatigue.

True

Smooth muscle tissue is found in the organs of the digestive tract, the walls of blood vessels, and the iris.

True

The discs that anchor the sarcomere on either end in skeletal muscle are absent from smooth muscle cells.

Z

Which letter is associated with the line that is a thin protein structure that serves as an attachment site for thin filament ends?

Z

A sarcomere is defined as the distance from one _______ to the next adjacent _________. (same answer)

Z disc

In tetany, a muscle cell is stimulated so frequently hate it is not allowed to relax at all between stimuli

incomplete

Multiunit smooth muscle cells are stimulated .

individually

Smooth muscle contraction is under control of the nervous system.

involuntary

During an ______ contraction, the length of the muscle does not change.

isometric

Myofibrils consist of bundles of short .

myofilaments

Thick filaments are assembled from bundles of the protein called .

myosin

Thick myofilaments are composed of bundles of protein molecules.

myosin

Which is not a protein found in thin filaments?

myosin

The junction between an axon and the muscle fiber itself is called a _____________ junction.

neuromuscular

Where a motor neuron axon terminal and a muscle cell meet is called a junction.

neuromuscular