Part B: Muscles A+P

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

A band

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

Which of the following accurately describes the structure of a muscle? Each skeletal muscle fiber branches many times so that it can synapse with many different neurons Muscle fibers are composed of many repeating subunits called fascicles 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

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

Describe troponin. (Select all that apply) It is bound to both actin and tropomyosin. It has a binding site for calcium ions. It binds to myosin during contraction. It is a globular protein composed of three subunits.

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

The perimysium is ______. a grouping of muscle fibers bundled together by epithelial tissue a thick connective tissue layer around each fasciculus a layer of connective tissue that surrounds the entire muscle a layer of dense irregular collagenous connective tissue around each fasciculus and muscle fiber a layer of epithelial tissue around the muscle

a thick connective tissue layer around each fasciculus

Myofibrils ______. are groups of muscle cells joined together by connective tissue are bundles of protein filaments are the outer covering or plasma membrane of a muscle cell extend from one end of the muscle fiber to the other

are bundles of protein filaments extend from one end of the muscle fiber to the other

In the sliding filament theory, ATP is involved in ______. the release of calcium from the sarcoplasmic reticulum at the start of contraction cocking or energizing the myosin heads the uptake of calcium into the sarcoplasmic reticulum at the end of contraction breaking the bond between actin and myosin

cocking or energizing the myosin heads the uptake of calcium into the sarcoplasmic reticulum at the end of contraction breaking the bond between actin and myosin

The function of a tendon is to ______. connect muscles to the skin separate individual fasciculi in a muscle connect muscles to bone attach a bone to another bone to increase stability attach one muscle to another muscle

connect muscles to bone connect muscles to the skin

The A band of the sarcomere ______. contains both actin and myosin proteins contains only myosin proteins contains the H zone and M line extends the length of the myosin myofilaments

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

A skeletal muscle myofilament ______. contains both actin and myosin proteins contains either actin or myosin proteins is also called a sarcomere is also called a muscle fiber

contains either actin or myosin proteins

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

fiber

A group of muscle _____ wrapped together in a connective tissue layer is called a _____. fibers, endomysium fascicles, fiber fibers, fasciculus fasciculus, myofibril

fibers, fasciculus

Mature skeletal muscle fibers are multinucleate because ______. 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

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

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

myofibril

The actin and myosin ______ form highly ordered units called sarcomeres which are joined end to end to form the ______. myofilaments, myofibrils fibers, myofilaments myofibrils, myofilaments myofilaments, fibers

myofilaments, myofibrils

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

myosin myofilament

The endomysium serves as a passageway for ______. Multiple choice question. endoplasmic reticulum and transverse tubules nerve fibers and blood vessels hormones and neurotransmitters

nerve fibers and blood vessels

Each fasciculus is surrounded by a thick connective tissue layer called the ______. perimysium fascia endomysium

perimysium

The major functions of the muscular system include ______. respiration production of hormones body movement constriction of organs and vessels

respiration production of hormone constriction of organs and vessels

The structure within a muscle fiber that extends from one Z disk to another Z disk is a(n) ______. sarcomere H zone I band A band

sarcomere

The type of muscle that is predominately responsible for the production of body heat to maintain temperature is _____________ muscle.

skeletal

Striated, multinucleate myofibers would be classified as ________ muscle tissue; striated, uninucleate, branching myofibers are _____ muscle and non-striated, filiform myofibers are _____ muscle. smooth, skeletal, cardiac skeletal, smooth, cardiac cardiac, skeletal, smooth skeletal, cardiac, smooth

skeletal, cardiac, smooth

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

striated

Muscle excitability is defined as the ability ______. to contract when stretched beyond the normal resting length to respond to a stimulus of a muscle to shorten forcefully of a muscle to recoil to its original resting length being stretched

to respond to a stimulus

Tube-like invaginations of the sarcolemma that conduct action potentials toward the center of the muscle fiber are called _____. transverse tubules sarcoplasmic reticulum sarcolemma

transverse tubules

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

troponin

A whole muscle is typically innervated by ______. more than one neuron a single neuron a neuron and all of the muscle cells it synapses with a collection of cell bodies bundled together

more than one neuron

pecialized nerve cells that stimulate muscles to contract are called ______. motor neurons satellite cells muscle fibers sensory neurons

motor neurons

The filamentous protein network that serves as the attachment site for actin myofilaments is called the _____. I band A band M line Z disk

Z disk

The boundaries of the sarcomere are defined by the _____. H zone M lines Sarcolemma Z disks

Z disks

A sarcolemma is ______. a transverse tubule a muscle fiber a cell membrane cytoplasm

a cell membrane

Which is a delicate layer of connective tissue that separates individual muscle fibers within each fascicle? Endomysium Perimysium Epimysium

Endomysium

Each _____ includes a Z disk and extends from each side of the Z disk to the ends of the myosin myofilaments. muscle fiber I band A band sarcomere

I band

List the characteristics or structures that enable automaticity in cardiac muscle? Intercalated disks The specialized arrangement of the sarcomeres Branched fibers Its uninucleate state

Intercalated disks Branched fibers

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

Several myoblasts fuse to form a single myofiber.

The muscular fascia: compartmentalizes individual muscles or groups of muscles is a layer of loose connective tissue surrounds individual fascicles a layer of deep irregular tissue

compartmentalizes individual muscles or groups of muscles a layer of deep irregular tissue

A skeletal muscle myofilament ______. contains both actin and myosin proteins is also called a sarcomere contains either actin or myosin proteins is also called a muscle fiber

contains either actin or myosin proteins

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 _____. reproducing using ATP contracting regenerating

contracting

The basic structural and functional unit of a skeletal muscle fiber is called the ______________ it is the smallest unit of skeletal muscle that is capable of contracting.

sarcomere

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

sarcomeres, myofibrils

The cytoplasm of a muscle cell is called the

sarcoplasm

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

sarcoplasmic

The property of excitability is best illustrated by which of the following scenarios? A cardiac muscle cell contracts without being stimulated by the nervous or endocrine systems. A hormone binds to smooth muscle cells in the wall of a blood vessel causing them to contract. A motor neuron signals a skeletal muscle fiber and it contracts.

A hormone binds to smooth muscle cells in the wall of a blood vessel causing them to contract. A motor neuron signals a skeletal muscle fiber and it contracts.

How are muscle fibers and muscle fascicles structurally related to each other? A muscle fasciculus is composed of groups of muscle fibers bundled together. Muscle fibers and muscle fascicles are both structures within a muscle cell. A muscle fiber is composed of muscle fascicles bundled together. Muscle fiber is another name for a muscle fascicle.

A muscle fasciculus is composed of groups of muscle fibers bundled together.

Describe the epimysium. The epimysium is a layer of adipose rich tissue that provides muscle with nutrients and gas exchange. The epimysium is a layer of dense collagenous connective tissue that surrounds a muscle. The epimysium is a supportive layer of irregular connective tissue which surrounds each individual muscle fiber. The epimysium is a layer of heavy connective tissue that surrounds each fasciculus.

The epimysium is a layer of dense collagenous connective tissue that surrounds a muscle.

List the arrangement of connective tissue layers from most superficial to deepest in a muscle. The endomysium overlays the perimysium which overlays the epimysium which overlays the muscular fascia. The epimysium overlays the perimysium which overlays the endomysium which overlays the muscular fascia. The muscular fascia overlays the epimysium which overlays the perimysium which overlays the endomysium. The muscular fascia overlays the perimysium which overlays the endomysium which overlays the epimysium.

The muscular fascia overlays the epimysium which overlays the perimysium which overlays the endomysium.

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

The passive lengthening of muscle The process of exhalation when your muscles recoil back to their original length

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

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

Energy from the breakdown of ATP is used to ______. move troponin off the F actin move tropomyosin off of the myosin binding site on the actin move the myosin heads during contraction move calcium ions into the sarcoplasmic reticulum release the cross-bridges

move the myosin heads during contraction move calcium ions into the sarcoplasmic reticulum release the cross-bridges

The properties of myosin heads that allow for sarcomere contraction include ______. the heads are ATPase enzymes the heads have active sites for the binding of actin the heads are attached to the rod portion by a hinge region that can bend and straighten during contraction the heads have active sites for the binding of calcium

the heads are ATPase enzymes the heads have active sites for the binding of actin the heads are attached to the rod portion by a hinge region that can bend and straighten during contraction