Chapter 9 Anatomy, Muscular System

Skeletal muscle tissue is ______. Voluntary Involuntary

Voluntary

The boundaries of the sarcomere are defined by the ______. M lines H zones A bands Z discs

Z discs

The A band contains ______. only actin only myosin actin and myosin

actin and myosin

During contraction of the sarcomere, the Z disk helps hold the ______ in place. tropomyosin molecules troponin molecules actin myofilaments myosin myofilaments

actin myofilaments

A sarcomere is formed from the arrangement of________and myosin myofilaments.

actin or thin

Which of the following accurately describes the structure of a muscle?(multiple choice) -A skeletal muscle fiber is a single, long, cylindrical cell containing several peripherally located nuclei. -Muscle fibers are composed of many repeating subunits called fascicles. -Each skeletal muscle fiber branches many times so that it can synapse with many different neurons. -A single skeletal muscle fiber can extend from one end of a muscle to the other.

-A skeletal muscle fiber is a single, long, cylindrical cell containing several peripherally located nuclei. -A single skeletal muscle fiber can extend from one end of a muscle to the other.

The A band of the sarcomere ______.(multi choice) -Contains both actin and myosin proteins -extends the length of the myosin myofilaments -contains the H zone and M line -contains only myosin proteins

-contains both actin and myosin proteins -extends the length of the myosin myofilaments -contains the H zone and M line

The I band ______. -extends from the M line to the Z disks -consists of only myosin myofilaments on each side of the Z disk -extends from each side of the Z disk to the ends of the myosin myofilaments -consists of actin myofilaments on each side of the Z disk

-extends from each side of the Z disk to the ends of the myosin myofilaments -consists of actin myofilaments on each side of the Z disk

A myofibril is about ______ than a human hair. 60 times larger 60 times smaller 6 times larger 6 times smaller

6 times smaller

The area of the sarcomere where the actin and myosin myofilaments overlap is called the ______. I band A band h zone z disk

A band

The area of the sarcomere where the actin and myosin myofilaments overlap is called the ______. h zone z disk A band I band

A band

The sarcolemma is ______. a cell membrane smooth ER cytoplasm

A cell membrane

Choose titin's roles in muscle contraction.(multiple choice) Accounts for muscle's extensibility and elasticity Allows the sarcomere to recoil and stretch Helps to hold the actin myofilaments in position Accounts for muscle's excitability

Accounts for muscle's extensibility and elasticity Allows the sarcomere to recoil and stretch

Which is the thinnest myofilament? Myosin Actin

Actin

The all or none principle applies to_______potentials.

Action

Choose titin's roles in muscle contraction.(multiple choice) Allows the sarcomere to recoil and stretch Accounts for muscle's extensibility and elasticity Helps to hold the actin myofilaments in position Accounts for muscle's excitability

Allows the sarcomere to recoil and stretch Accounts for muscle's extensibility and elasticity

An action potential has two phases. The first phase is_______and the second phase is______.

Blank 1: depolarization Blank 2: repolarization

Sodium is more abundant in which fluid compartment? Inside the plasma membrane Outside the plasma membrane

Outside the plasma membrane

Potassium and sodium ions play an important role in resting membrane potential. Which ion has the larger concentration inside the cell? Potassium Sodium

Potassium

Identify characteristics of hypertrophy.(multiple choice) -Is a substantial increase in the numbers of muscle fibers in a muscle -Involves a wasting away of unused muscle tissue -Can occur in response to exercise -Is a decrease in muscle size due to the wasting of muscle cells -Is an increase in the size of a muscle fiber

Can occur in response to exercise Is an increase in the size of a muscle fiber

Potassium is more abundant in which fluid compartment? Compartment inside of the cell Compartment outside of the cell

Compartment inside of the cell

The ability of muscle to shorten forcefully is called ______. extensibility contractility elasticity excitability

Contractility

During contraction, the I Zone will ______ in size. increase decrease not change

Decrease

What does the sliding filament theory of muscle contraction predict about myofilaments and sarcomere length? During contraction, the total length of the myosin myofilament decreases. During contraction, the thin myofilaments slide past the thick myofilaments. During contraction, the total length of the sarcomere decreases. During contraction, the total length of the actin myofilament decreases.

During contraction, the thin myofilaments slide past the thick myofilaments. During contraction, the total length of the sarcomere decreases.

During muscle contraction, each ______ monomer has an open active site to bind with the protein myosin. troponin tropomyosin G-actin

G-actin

What is the area in the center of the A band where there are no actin myofilaments? H zone I band M line

H zone

What is the area in the center of the A band where there are no actin myofilaments? H zone M line I band

H zone

What is the area in the center of the A band where there are no actin myofilaments? H zone I band M zone

H zone

Enlargement of muscles in children and adults that results from an increase in the size of each muscle fiber is called_______.

Hypertrophy

During a contraction, which areas of the sarcomere are most likely to either disappear or decrease? A band Z disk I band H zone

I band H zone

In a resting cell, the sodium-potassium pump pumps potassium ______ the cell. into out of

Into

When a cell is stimulated the membrane depolarizes. How does that happen? Ion gates open and calcium ions rush out of the cell. Ion gates open and negatively charged ions rush out of the cell. Ion gates open and positively charged sodium ions rush into the cell. Ion gates open and negatively charged ions rush into the cell.

Ion gates open and positively charged sodium ions rush into the cell.

Which are true of troponin? It is bound to both actin and tropomyosin. It is a globular protein composed of three subunits. It binds to myosin during contraction. It has a binding site for calcium ions.

It is bound to both actin and tropomyosin. It is a globular protein composed of three subunits. It has a binding site for calcium ions.

What is the neuromuscular junction? It is the site in the spinal cord where nerve impulses from the somatic receptors are received. It is the site where the nerve fiber innervates the muscle fiber. It is where the synaptic bulb attached to the T-tubule. It is the passageway into the muscle group for arteries and veins.

It is the site where the nerve fiber innervates the muscle fiber.

The concentration of sodium ions is______in the cytosol of the cell at rest than it is in the surrounding extracellular fluid.

LOWER

Titin is the ______ protein in humans. smallest largest most abundant least abundant

Largest

Titin is the______ protein in humans. most abundant least abundant smallest largest

Largest

Which is an example of the contractility of muscle? -The process of exhalation when your muscles recoil back to their original length -The passive lengthening of the muscle -A conscious decision to lift your arm and wave at a friend -Lifting a textbook

Lifting a textbook

An I band is a ______ staining region of a sarcomere. darker lighter

Lighter

An I band is a ______ staining region of a sarcomere. lighter darker

Lighter

The line in the center of the H zone that holds myosin myofilaments in place is the_______line.

M Line

Name the structure found in the middle of the H zone that attaches to the center of the myosin myofilaments Z line I band Tropomyosin G band M line

M line

Specialized nerve cells that stimulate muscles to contract are called _____.(Yo la conocí en un taxi) sensory neurons muscle fibers satellite cells motor neurons

MOTOR NEURONS

A neuron that innervates skeletal muscle fibers is called a(n)_______neuron.🚗

Motor

The muscle plasma membrane in the area of the neuromuscular junction is the ______. motor end plate synaptic cleft sarcomere ATPase enzyme

Motor end plate

Which of the following are characteristics of a skeletal muscle fiber? Spindle-shaped Multinucleate Branched Cylindrical

Multinucleate Cylindrical

Muscle fibers develop from less mature, multinucleated cells called______. chondroblasts erythroblasts osteoblasts myoblasts

Myoblasts

Each ______ is a threadlike structure, approximately 1-3 micrometers in diameter, that extends from one end of the muscle fiber to the other. muscle fiber fasciculus sarcomere myofibril

Myofibril

Each G-actin monomer has an active site for the binding of what molecule? Myosin F actin Calcium ATP

Myosin

What part of the myosin filaments bind to actin? Myosin heads Myosin tails

Myosin heads

Which of the following ionic movements causes the repolarization phase of the action potential? The movement of a large number of sodium ions out of the cell. The movement of a large number of potassium ions into the cell. The movement of a large number of potassium ions out of the cell. The movement of a large number of sodium ions into the cell.

The movement of a large number of potassium ions out of the cell.

The sodium-potassium ion pump uses active transport therefore it requires______. a favorable concentration gradient a favorable electrostatic gradient an investment of ATP

an investment of ATP

Tendons are formed from ______. nerve fibers muscle fibers collagen fibers

collagen fibers

A skeletal muscle myofilament ______. contains both actin and myosin is the same thing as sarcoplasmic reticulum is the same thing as a muscle cell contains either actin or myosin

contains either actin or myosin

A skeletal muscle myofilament ______. contains either actin or myosin is the same thing as sarcoplasmic reticulum is the same thing as a muscle cell contains both actin and myosin

contains either actin or myosin

The H zone______. contains both myosin and actin myofilaments contains only actin myofilaments contains only myosin myofilaments

contains only myosin myofilaments

The sarcomere is called the basic functional unit of a muscle fiber because it is the smallest part of the fiber that is capable of ______. using ATP contracting recoil regenerating

contracting

After stimulation, positive ions enter the cell. This causes the membrane to______. depolarize repolarize hyperpolarize become less permeable

depolarize

When the membrane potential of a cell becomes more positive than its resting potential, the cell is ______. repolarized depolarized hyperpolarized

depolarized

Another name for a single skeletal muscle cell is a skeletal muscle_______.(Its not tissue.)

fiber or myocyte

Myosin heads bind to ______. troponin myosin heads globular actin tropomyosin

globular actin

Mature skeletal muscle fibers are multinucleate because ______. -many myoblast precursor cells, each with its own nucleus, fuse together to form one mature fiber -the nuclei within a developing muscle fiber divide multiple times

many myoblast precursor cells, each with its own nucleus, fuse together to form one mature fiber

During contraction of the sarcomere, the M line helps hold the ______ in place. troponin molecules myosin filaments tropomyosin molecules actin filaments

myosin filaments

The phases of the action potential include ______.(multiple choice) repolarization threshold resting phase depolarization

repolarization depolarization

The plasma membrane of a muscle fiber is called the__________.

sarcolemma

The ______ is the basic structural and functional unit of skeletal muscle. myosin filament sarcolemma sarcomere myofibril

sarcomere

The sliding filament theory states that during contraction ______. -sarcomeres shorten because myosin myofilaments become shorter as subunits are added to actin myofilaments -sarcomeres shorten because actin myofilaments become shorter as subunits are added to myosin myofilaments -sarcomeres shorten because actin myofilaments slide past the myosin myofilaments -sarcomeres shorten because myosin myofilaments slide past actin myofilaments towards the M line

sarcomeres shorten because actin myofilaments slide past the myosin myofilaments

The actin and myosin myofilaments form highly ordered units called ______, which are joined end to end to form the ______. fascicles, M line myofibrils, sarcomeres sarcomeres, myofibrils muscle, fascicle

sarcomeres, myofibrils

The actin and myosin myofilaments form highly ordered units called ______, which are joined end to end to form the ______. myofibrils, sarcomeres fascicles, M line sarcomeres, myofibrils muscle, fascicle

sarcomeres, myofibrils

In a muscle cell, the highly specialized, smooth endoplasmic reticulum is called the ______. sarcolemma sarcoplasm sarcoplasmic reticulum transverse tubule

sarcoplasmic reticulum

Contractility is the ability of a muscle to ______forcefully. shorten lengthen recoil

shorten

Voluntary movements such as raising your hand are produced by the contraction of_______muscle cells.

skeletal

The H zone is ______ than the A band. smaller larger

smaller

Muscles are connected to bones or the skin by________. (T)

tendons or aponeuroses

Describe what is meant by the threshold. It is ______. the minimum voltage that must be reached in order to cause the opening of the voltage gated ion channels of the axon hillock the maximum voltage that the cell reaches during the action potential the voltage of the smallest action potential that can be generated by the cell the minimum area of the axon that must be stimulated to generate an action potential

the minimum voltage that must be reached in order to cause the opening of the voltage gated ion channels of the axon hillock

A chain of small units of globular actin make up ______. tropomyosin troponin F actin myosin

F Actin

A chain of small units of globular actin make up ______. ropomyosin troponin myosin F actin

F actin

Another name for a skeletal muscle cell is a muscle ______. myofibril myofilament sarcolemma fascicle fiber

Fiber

The return of the membrane potential to its resting value is called ______. repolarization depolarization

Repolarization

The plasma membrane of a muscle fiber is called the________.

Sarcolemma

Name the structure or region from one blue line to the other blue line in the figure. Myosin myofilament Titin Actin myofilament Sarcomere

Sarcomere

The structure that is a modified form of smooth endoplasmic reticulum located in muscle cells is called_____reticulum.

Sarcoplasmic

Which best describes how skeletal muscle fibers are produced? Each myoblast gives rise to a single myofiber. Multinucleate myoblasts divide to form multinucleate myofibers. Several myoblasts fuse to form a single myofiber. Multinucleate myoblasts divide to form uninucleate myofibers.

Several myoblasts fuse to form a single myofiber.

Hypertrophy of muscles results from an increase in the______ size of muscle fibers number of muscle fibers

Size of muscle fibers

Which muscle tissue type is the most abundant? Skeletal Cardiac Smooth

Skeletal

List the types of muscle tissue.(Multiple choice 3) Skeletal Cardiac Smooth Tendon Cartilaginous

Skeletal Cardiac Smooth

Which are types of muscle tissue? Smooth, skeletal, and cardiac Stratified and simple Dense and loose Smooth, connective, and nervous

Smooth, skeletal, and cardiac

When examined in a longitudinal section, skeletal muscle has alternating light and dark bands producing a(n) ______ appearance. glassy striated smooth rough

Striated

A neuromuscular junction is also called a ______. cleft neurotransmitter sarcolemma synapse

Synapse

The space between a presynaptic terminal and a muscle fiber is called a__________cleft.

Synaptic Cleft

At the neuromuscular junction, each presynaptic terminal contains numerous small, spherical sacs called ______, which contain acetylcholine. sarcoplasmic reticulum mitochondria synaptic vesicles motor end plates

Synaptic Vesicles

The organelles that are located within the presynaptic terminals and contain neurotransmitter are called synaptic________.

Synaptic Vesicles

What is the space between the presynaptic terminal and muscle fiber called? Synaptic cleft Neural groove Synaptic fissure Myosulcu

Synaptic cleft

What are the transverse (T) tubules? -They are composed of the actin and myosin myofilaments. -They are the main component of the cytoskeleton of the cell. -They are tube-like invaginations of the sarcolemma that extend inward throughout the muscle cell. -They are modified segments of smooth endoplasmic reticulum which store calcium needed for contraction.

They are tube-like invaginations of the sarcolemma that extend inward throughout the muscle cell.

What are the transverse (T) tubules? -They are the main component of the cytoskeleton of the cell. -They are modified segments of smooth endoplasmic reticulum which store calcium needed for contraction. -They are tube-like invaginations of the sarcolemma that extend inward throughout the muscle cell. -They are composed of the actin and myosin myofilaments.

They are tube-like invaginations of the sarcolemma that extend inward throughout the muscle cell.

In order for local potentials to trigger an action potential, the membrane potential must reach a level called the ______. spike resting membrane potential threshold

Threshold

Which of the following molecules covers the active sites on the G-Actin molecule when the muscle fiber is relaxed? Tropomyosin Titin Troponin F actin Calcium

Tropomyosin

A skeletal muscle fiber is ______ a skeletal muscle cell. different from the same as

the same as

The molecule that inhibits the binding of myosin to actin by blocking the binding site is ______. troponin calcium ATP tropomyosin

tropomyosin

Within a myofibril, calcium-binding sites are found on ______. actin tropomyosin troponin myosin

troponin